thermal trip

• Check Stock
• Sales Portal

Thermal Overcurrent Circuit Breakers

Typical applications.

Thermal circuit breakers (circuit protectors, resettable fuses, circuit breakers for equipment protection) are ideally suited to overload protection of motors, transformers, magnetic valves, on-board electrical systems and low voltage lines.

The trip time of thermal circuit breakers depends on the height and of the duration of the overload current and the ambient temperature. With higher current ratings, the bimetal or hot wire is heated up until the defined trip time is reached and the device ensures genuine physical isolation of the contacts.

Thermal circuit breaker, integral type, single pole

Thermal circuit breaker for pcb mounting, single pole

Thermal circuit breaker for snap-in mounting, single pole

Thermal circuit breaker for threadneck panel mounting, single pole

Thermal circuit breaker with manual release button, plug-in or snap in panel mounting

129-L11-H-KF

Thermal automotive circuit breaker with manual release, for base mounting

Push-push thermal switch/circuit breaker combination, single pole

Single pole thermal circuit breaker, integral type

Thermal circuit breaker for snap-in panel mounting, single pole

Thermal circuit breaker for threadneck panel mounting, double pole, one pole thermally protected

Thermal automotive circuit breaker with automatic reset function

Miniaturised thermal automotive circuit breaker with colour-coded manual release

Thermal circuit breaker, plug-in type, single pole, switching function optional

Thermal circuit breaker for snap-in panel mounting, rocker operated, fast acting

Miniaturised thermal circuit breaker for pcb mounting, fast acting

Miniaturised thermal circuit breaker for threadneck panel mounting, fast acting

Automotive thermal circuit breaker, colour-coded housing, standard fuseblock mounting

Automotive thermal circuit breaker with manual release option

Automotive thermal circuit breaker with automatic reset function

Single pole, thermal miniaturised circuit breaker designed for automotive applications

Single pole thermal reset circuit breaker in a miniaturised design intended for threadneck or snap-in mounting, dimensions: 32.0 x 27.0 x 13.6 mm.

3120-N, thermal circuit breaker, snap-in mounting, 1-pole, 2-pole

Thermal circuit breaker with rocker actuation, single, double or three pole

Thermal circuit breaker with rocker actuation, single pole, water splash protected (IP66)

Single pole three-position switch, water splash protected (IP66)

Thermal circuit breaker with push buttons, three pole

Thermal circuit breaker for threadneck panel mounting

Thermal circuit breaker for flange mounting and manual release option

Thermal circuit breaker with threadneck, push-push actuation

Thermal circuit breaker for threadneck panel mounting, with auxiliary contacts

Single pole bimetal operated motor protection control, surface mounting, autoreset

Interactive Virtual Sample Kit

E-T-A's new interactive sample case features circuit breakers, relays, and power distribution modules. With the click of your mouse you can:

• Spin products with 360° CAD product viewer
• Filter products by attributes
• View product datasheets
• Add samples to a bag to request physical samples

Build your custom sample kit today

Fuse vs. circuit breaker: How to choose the right device for your application

Is a fuse or circuit breaker best for your design? Here are some pointers to help you decide. Three main factors go into choosing between circuit breakers and fuses: Convenience for the user, cost, and degree of protection. This white paper will give you guidance on what circuit protection device is best for your equipment.

Read White Paper

12 Most Common Mistakes When Specifying Circuit Protection for Equipment

It's only a circuit breaker. Yet there is enough complexity and confusion when it comes to specifying circuit protection that many engineers are designing equipment with too little or too much protection. Under protected circuits leave equipment vulnerable to damaging electrical surges. Over protected circuits add cost and can lead to nuisance tripping. Like Goldilocks and the three bears, the goal is to specify circuit protection that is "just right".

• International

• Hazard Categories and Special Symbols
• Please Note
• Related Documents
• Isolation Characteristics
• Unit-Mount Circuit Breaker Description
• Unit Mount Circuit Breaker Accessories
• Sealing Accessories
• I-Line Circuit Breaker Description
• I-Line Circuit Breaker Accessories
• PowerPact B Frame Ratings

Thermal Protection

Ac magnetic trip levels, dc magnetic trip levels.

• Temperature
• Extreme Atmospheric Conditions
• Electromagnetic Disturbance
• Overview of PowerPact B Insulation Accessories
• PowerPact B Insulation Accessories
• PowerPact B Equipment Installation Requirements
• Minimum Distances for Side-by-Side PowerPact B Installation
• PowerPact B Minimum UL Enclosure Volume
• Minimum PowerPact B Clearance Without Insulation Accessories
• Minimum PowerPact B Clearance with Interphase Barriers
• Minimum Clearance for PowerPact B with Long Terminal Shields
• Minimum Clearance for PowerPact B with Live Parts
• Minimum Clearance Between PowerPact B Backplate and Uninsulated Power Connectors
• PowerPact B Front Face with Toggle Handle
• Device Identification for PowerPact B with Toggle Handle
• Opening and Closing with the Toggle Handle
• Resetting with the Toggle Handle After a Trip
• Testing the Trip Mechanism with a Toggle Handle
• Locking Options for the Toggle Handle
• PowerPact B Front Face with Direct Rotary Handle
• Device Identification for PowerPact B with Direct Rotary Handle
• Opening and Closing with a Direct Rotary Handle
• Resetting with the Direct Rotary Handle After a Trip
• Testing the Trip Mechanism with a Direct Rotary Handle
• Locking Options for the Direct Rotary Handle
• Inserting Padlocks in the PowerPact B Rotary Handle
• Overriding the Rotary Handle Door Interlock
• PowerPact B Front Face with Front Extended Handle
• Device Identification for PowerPact B with Front Extended Handle
• Opening and Closing with the Front Extended Handle
• Resetting with the Front Extended Handle After a Trip
• Testing the Trip Mechanism with a Front Extended Handle
• Locking Options for the Front Extended Handle
• Inserting Padlocks in the Extended Rotary Handle
• Locking the Circuit Breaker with an Extended Rotary Handle in the O (OFF) Position When the Door is Open
• Overriding the Extended Rotary Handle Door Interlock
• PowerPact B Front Face with Side Rotary Handle
• Device Identification for PowerPact B with Side Rotary Handle
• Opening and Closing with the Side Rotary Handle
• Resetting with the Side Rotary Handle After a Trip
• Testing the Trip Mechanism with a Side Rotary Handle
• Locking Options for the Side Rotary Handle
• Inserting Padlocks in Side Rotary Handle
• Class 9421 Circuit Breaker Operating Mechanism
• Complete Kits for Class 9421 Operating Mechanism
• PowerPact B Front Face with 9421 Rotary Handle
• Device Identification for PowerPact B with 9421 Rotary Handle
• Opening and Closing with the 9421 Rotary Handle
• Resetting with the 9421 Rotary Handle After a Trip
• Testing the Trip Mechanism with a 9421 Rotary Handle
• Locking Options for the 9421 Rotary Handle
• Inserting Padlocks in the 9421 Rotary Handle
• Locking the Circuit Breaker with a 9421 Rotary Handle in the O (OFF) Position When the Door is Open
• Overriding the 9421 Door Interlock
• Class 9422 Circuit Breaker Operating Mechanism
• Complete 9422 Kits
• Class 9422 Flexible Cable Operating Mechanisms
• PowerPact B Front Face with 9422 Toggle Handle
• Device Identification for PowerPact B with 9422 Toggle Handle
• Opening and Closing with a 9422 Toggle Handle
• Resetting with the 9422 Toggle Handle After a Trip
• Resetting the 9422 Toggle Handle After a Trip Caused by an Electrical Fault
• Testing the Trip Mechanism with a 9422 Toggle Handle
• Locking Options for the 9422 Toggle Handle
• Overriding the 9422 Door Interlock
• Summary of Electrical Auxiliary Devices
• Slots for Electrical Auxiliary Devices
• Characteristics of PowerPact B Indication Contacts
• Operation of PowerPact B Auxiliary Indication Contacts
• PowerPact B-Frame Remote Electrical Trip
• List of Checks and Inspections
• A: Insulation Tests and Dielectric Strength Tests
• B: Temperature Rise Tests
• C: Inspect Switchboard
• D: Check Compliance with the Diagram
• E: Inspect Mechanical Equipment
• F: Check Mechanical Operation
• G: Clean Equipment
• Environmental and Operating Conditions
• Regular Preventive Maintenance
• Maintenance Operations Required
• Taking Precautions Before Responding to a Trip
• Identifying the Cause of the Trip
• Checking Equipment After a Trip
• Resetting the Circuit Breaker
• Repetitive Tripping
• Circuit Breaker Does Not Close
• PowerPact B DC Systems
• PowerPact B DC Wiring Diagrams
• Grounded B-Phase Systems (Corner-Grounded Delta)
• Indication Contacts
• Remote Operation (MN/MX Voltage Release)

For the best experience of this site, please enable Javascript for the www.productinfo.schneider-electric.com domain.

Thermal-Magnetic Protection for Circuit Breakers

Thermal-magnetic protection provides the following features for general-purpose applications:

Thermal protection against overload, with fixed threshold In.

Instantaneous protection against short circuits, with fixed threshold Ii.

The following figure shows the trip curve.

In Thermal protection pickup

Ii Instantaneous trip point

The thermal protection pick-up value cannot be adjusted. Its value for each frame rating is shown below.

The Time Current Curves (trip curves) provide the complete time-current characteristics of the circuit breaker when applied on an AC system. When applying thermal-magnetic circuit breakers on DC systems, they retain the same thermal tripping characteristics, but the magnetic trip levels vary. See table for the appropriate DC magnetic hold and trip levels.

Show QR code for this page

Was this helpful?

Contact Information

Legal information.

The information provided in this document contains general descriptions, technical characteristics and/or recommendations related to products/solutions.

This document is not intended as a substitute for a detailed study or operational and site-specific development or schematic plan. It is not to be used for determining suitability or reliability of the products/solutions for specific user applications. It is the duty of any such user to perform or have any professional expert of its choice (integrator, specifier or the like) perform the appropriate and comprehensive risk analysis, evaluation and testing of the products/solutions with respect to the relevant specific application or use thereof.

The Schneider Electric brand and any trademarks of Schneider Electric SE and its subsidiaries referred to in this document are the property of Schneider Electric SE or its subsidiaries. All other brands may be trademarks of their respective owner.

This document and its content are protected under applicable copyright laws and provided for informative use only. No part of this document may be reproduced or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), for any purpose, without the prior written permission of Schneider Electric.

Schneider Electric does not grant any right or license for commercial use of the document or its content, except for a non-exclusive and personal license to consult it on an "as is" basis.

Schneider Electric reserves the right to make changes or updates with respect to or in the content of this document or the format thereof, at any time without notice.

To the extent permitted by applicable law, no responsibility or liability is assumed by Schneider Electric and its subsidiaries for any errors or omissions in the informational content of this document, as well as any non-intended use or misuse of the content thereof.

© 2018 – Schneider Electric

• Mechanical & Electrical

Basics of low-voltage circuit breakers

A circuit breaker is designed to keep an undesirably large amount of current, voltage, or power out of a given part of an electrical circuit. industrial circuit breaker categories tend to follow voltage classes, which are divided according to magnitude. the ieee divides voltage systems into four classes listed in the table titled "ieee voltage classifications..

A circuit breaker is designed to keep an undesirably large amount of current, voltage, or power out of a given part of an electrical circuit.

Industrial circuit breaker categories tend to follow voltage classes, which are divided according to magnitude. The IEEE divides voltage systems into four classes listed in the table titled “IEEE voltage classifications.”

Circuit breakers found in industrial plants accommodate all voltage levels. However, low and medium-voltage circuit breakers comprise the lion’s share of switchgear used in industrial manufacturing plants. The focus of this article is limited to low-voltage circuit breakers.

The main classifications of low-voltage circuit breakers are “toggle” mechanism and two-step stored energy mechanism circuit breakers. The molded-case circuit breaker (MCCB) (Fig. 1) has a toggle mechanism with a distinct tripped position, which is typically midway between on and off.

The low-voltage power circuit breaker (LVPCB) (Fig. 2) has a two-step stored energy mechanism. This type of mechanism uses an energy storage device, such as a spring, that is “charged” and then released, or “discharged,” to close the circuit breaker. The LVPCB is older technology. Therefore the trend is away from LVPCB and toward insulated case circuit breakers (ICCB) because of reduced maintenance. No dust or contaminants can get into the sealed compartments of the ICCB and components are designed to ensure longer life.

Circuit breaker construction

As shown in Fig. 3, most circuit breakers have five main components:

Frame or molded case

Operating mechanism

Arc extinguishers and contacts

Terminal connectors

Trip bar or element.

The frame provides an insulated housing and is used to mount the circuit breaker components. The frame determines the physical size of the circuit breaker and the maximum allowable voltage and current. The operating mechanism provides a means of opening and closing the breaker contacts. In addition to indicating whether the breaker is open or closed, the operating mechanism handle indicates when the breaker has opened automatically (tripped) by moving to a position between on and off. To reset the circuit breaker, first move the handle to the “off” position, and then to the “on” position.

The arc extinguisher confines, divides, and extinguishes the arc drawn between contacts each time the circuit breaker interrupts current. The arc extinguisher is actually a series of contacts that open gradually, dividing the arc and making it easier to confine and extinguish (Fig. 4). Arc extinguishers are generally used in circuit breakers that control a large amount of power, such as those found in power distribution panels. Small power circuit breakers, such as those found in lighting panels, may not have arc extinguishers.

Terminal connectors are electrically connected to the contacts of the circuit breaker and provide the means of connecting the circuit breaker to the circuit. The trip element is the part of the circuit breaker that senses the overload condition and causes the circuit breaker to trip or break the circuit. Some circuit breakers use solid-state trip units, which use current transformers and solid-state circuitry.

Trip elements

The thermal trip element circuit breaker, like a delay fuse, protects a circuit from a small overload that continues for a long time (Fig. 5). The larger the overload, the faster the circuit breaker trips. The thermal element also protects the circuit from temperature increases. A magnetic circuit breaker trips instantly when the preset current is present. In some applications, both types of protection are desired. Rather than use two separate circuit breakers, a single trip element combining thermal and magnetic trip elements is used.

A magnetic trip element circuit breaker uses an electromagnet in series with the circuit load. With normal current, the electromagnet does not have enough attraction to the trip bar to move it; the contacts remain closed. The strength of the magnetic field of the electromagnet increases as current through the coil increases. As soon as the current in the circuit becomes large enough, the trip bar is pulled toward the magnetic element (electromagnet), the contacts are opened, and the current stops.

The amount of current needed to trip the circuit breaker depends on the size of the gap between the trip bar and the magnetic element. On some circuit breakers, this gap, and therefore the trip current, is adjustable.

In the thermal-magnetic trip element circuit breaker, a magnetic element is connected in series with the circuit load, and the load current heats a bimetallic element. Thermal-magnetic trip element operation is detailed in Fig. 6a and 6b.

Trip-free and nontrip-free circuit breakers

Circuit breakers are classified as being trip free or nontrip free. A trip-free circuit breaker is a circuit breaker that trips even if the operating mechanism is held in the “on” position. A nontrip-free circuit breaker can be reset and/or held “on” even if an overload or excessive heat condition is present. In other words, a nontrip-free circuit breaker can be bypassed by holding the operating mechanism “on.”

Trip-free circuit breakers are used on circuits that cannot tolerate overloads and on nonemergency circuits. Examples of these are precision or current sensitive circuits, nonemergency lighting circuits, and nonessential equipment circuits. Nontrip-free circuit breakers are used for circuits that are essential for operations. Examples of these circuits are emergency lighting, required control circuits, and essential equipment circuits.

Circuit breaker maintenance

Circuit breakers that can be accessed for maintenance require careful inspection and periodic cleaning. Before you attempt to work on circuit breakers, check the applicable technical manual carefully. Remove power to the circuit breaker before you work on it. Tag the switch that removes the power from the circuit breaker to ensure that power is not applied while you are working.

Manually operate the circuit breaker several times to ensure the operating mechanism works smoothly. Inspect the contacts for pitting caused by arcing or corrosion. If pitting is present, smooth the contacts with a fine file or number 00 sandpaper.

Be certain the contacts make proper contact when the operating mechanism is in the “on” position.

Check the connections at the terminals to ensure the terminals and wiring are tight and free from corrosion. Check all mounting hardware for tightness and wear. Check all components for wear. Clean the circuit breaker completely.

When you have finished working on the circuit breaker, restore power and remove the tag from the switch that applies power to the circuit.

PLANT ENGINEERING magazine extends its appreciation to Eaton | Cutler-Hammer, E-T-A Circuit Breakers, Rockwell Automation, Schneider Electric, and Siemens Energy & Automation, Inc., for the use of their materials in the preparation of this article.

IEEE voltage classifications

Low-voltage systems.

&1000 Vac

Medium-voltage systems

>1000 Vac to

100,000 Vac*

High-voltage systems

>100,000 Vac to

230,000 Vac

Extra-high voltage systems

>230,000 Vac to 800,000 Vac

*Most medium-voltage systems are rated at 38000 Vac or less.

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our WTWH Media editorial team and getting the recognition you and your company deserve. Click here to start this process.

Related Resources

Privacy overview.

Circuit Protection Devices

Thermal trip element.

A thermal trip element circuit breaker uses a bimetallic element that is heated by the load current.

The bimetallic element is made from strips of two different metals bonded together. The metals expand at different rates as they are heated. This causes the bimetallic element to bend as it is heated by the current going to the load. Figure 19 shows how this can be used to trip the circuit breaker.

Figure 19, view A, shows the trip element with normal current. The bimetallic element is not heated excessively and does not bend. If the current increases (or the temperature around the circuit breaker increases), the bimetallic element bends, pushes against the trip bar, and releases the latch. Then, the contacts open, as shown in figure 19, view B.

The amount of time it takes for the bimetallic element to bend and trip the circuit breaker depends on the amount the element is heated. A large overload will heat the element quickly. A small overload will require a longer time to trip the circuit breaker.

PAY AFTER YOU PASS! All Courses FREE to Take - Pay only for the Certificate Record Dismiss

Username or Email Address

Remember Me

Uncategorized

Evolution of the molded case circuit breaker trip units and their value to customers.

Even though an 1879 patent filed by Thomas Edison provided a glimpse of the definition of what would become circuit breakers, fuses (use once and throw away) were the standard for the first 30-40 years in power distribution systems.1 In 1924, German inventor Hugo Stotz created and patented what was marketed as a re-settable fuse (Figure 1). It was a direct retrofit into common fuse panels of the day. The Stotz fuse incorporated a thermal element to detect and open contacts to clear overloaded or shorted circuits.2 This was a forerunner of the thermal-magnetic breaker (Figure 2) widely used in today’s power distribution systems.

How have circuit breakers evolved since the Stotz? More importantly, how can you take advantage of new circuit breaker technology to deliver to your clients a better tailored and user-friendly project? This brief article will focus specifically on the evolution of the breaker trip unit and the value this evolution provides to customers.

Circuit Breaker and Trip Unit

In order to understand what a trip unit is, let’s revisit the definition of a circuit breaker. A circuit breaker is a mechanical switching device designed to automatically detect and eliminate short circuits and overload current. A trip unit, specifically, is the “brain” of the circuit breaker as its function is to measure physical parameters such as electrical current and decide when to “trip” or rapidly open the mechanical contacts of the circuit breaker. At the bare minimum, a trip unit needs to offer overload and short circuit protection. In regard to the topic of evolution, the trip unit can be as simple as a bi-metallic strip, or now, as advanced as a computer. This evolution has opened the door to so much more than overload and short circuit protection – it’s opened a whole new world of protection, measurement, and control.

Let’s take a look at the evolution of the circuit breaker trip unit in four stages, starting with the basic thermal magnetic circuit trip unit, which is still the most widely used trip mechanism today.

Thermal Magnetic Circuit Trip Unit

The basic thermal magnetic circuit trip unit still provides a cost-effective solution for basic circuit protection and remains in widespread use. With the growth of critical electrical loads, the need for accurate and coordinated circuit protection has become much more important. However, the lower accuracy sensitivity offered by a thermal magnetic breaker cannot fully address this increasing demand. These shortcomings are amplified when you need breakers to trip in a coordinated fashion where only the problematic circuit is taken out of service. This is called selectivity and was a primary driver in the evolution from the thermal magnetic trip unit to the electronic trip unit which can provide a much higher degree of accuracy in sensing and responding to trip events.

Figure 3 exemplifies the typical response of a thermal magnetic breaker in the form of a time current curve (TCC). The X axis represents current and Y axis represents time, in seconds. The grid is logarithmic on both the X and Y axis. The breaker has two elements – ‘L’ or long time for the thermal, and ‘I’ for the magnetic. Note the width of the long-time element indicates a substantial lack of accuracy. Also note that the breaker’s response is significantly affected by temperature. There are two long time curve sections shown. The blue section is the ‘cold’ response and the orange section is the ‘hot’ response. The lack of accuracy makes coordination between thermal magnetic breakers difficult.

First Generation Electronic Trip Units

As noted earlier, this lack of accuracy, along with the growing need for coordinated circuit protection, drove the development of the electronic trip unit. First generation electronic trip units (Figure 4) were simple analog circuits comprised of resistors, capacitors, inductors, and transistors, however, they offered increased accuracy over their thermal magnetic cousins. Electronic trip breakers could be reasonably coordinated and be used to build a selectively coordinated distribution system.

Over the years, electronic trip units underwent incremental improvements including:

• Limited Adjustability – Provided ability to make basic adjustments to instantaneous and overload response to improve selectivity
• True RMS Sensing – Improved accuracy, bringing measurement much closer to the thermal response (not just looking at peak) of the current
• Thermal Memory – Ensured (even lacking the inherent “heater” present in original thermal magnetic breakers) that trip data could be retained and remembered for reporting
• Overall Improvement in Equipment Protection – Due to these enhancements which allowed more selectivity and eliminated the nuisance of premature trips which can damage the equipment

Modern Microprocessor Trip Units

As these electronic trip units continued to evolve, manufacturers used more and more sophisticated and integrated circuits which slowly evolved trip units into the modern microprocessor trip unit. The microprocessor trip unit provides even more improved protection accuracy and adjustability (ability to coordinate breakers closer together thus allowing additional breakers to operate in series IE levels of protection). Electronic trip unit breakers are commonly referred to as ‘LSI’ or ‘LSIG’ where ‘L’ is the long-time trip (60-600 sec), ‘S’ is the short time trip (0.1 to 60 sec), and ‘I’ is the instantaneous trip. ‘G’ is the optional ground fault trip. The ‘L’ and ‘S’ functions replace the thermal element in the thermal magnetic circuit breaker and the ‘I’ replaces the magnetic element. Figures 5 and 6 show the difference in response and adjustability between thermal magnetic and LSIG circuit breakers.

Figure 7 shows the time current curve of a typical breaker with a microprocessor LSI trip unit. Note the increased accuracy and adjustability in comparison with the thermal magnetic breaker.

This improved accuracy and adjustability of LSI breakers allowed for more advanced coordination of increasing layers of panels/circuit breakers in series.

Application Example

A building with a 2000A main switchboard and multiple power panels scattered throughout. Thermal magnetic breakers may allow up to three levels of coordination – switchboard main to switchboard feeder to power panel branch. Suppose the power panels were then feeding lighting panels. The lighting panel branch circuits can not be coordinated as it is the fourth level of coordination. If LSI breakers were used, the same system could be coordinated through the lighting panel and possibly with an additional panel in between (5 levels).

These evolving microprocessor trip units also provide much improved coordination with different types of protective devices such as motor starters, fuses, and relays, as well as the key ZSI (Zone Selective Interlocking) ability which allows planned overlap to gain maximum protection.

One big weakness that had yet to evolve was the advancement of sensors. So, while these electronic microprocessor trip units along with the right add-on equipment could provide early versions of metering from the circuit itself, the data was very inaccurate.

Today’s Advanced Next Generation Microprocessor Trip Units

Finally, we come to today’s advanced microprocessor trip units which are still microprocessor based, but because of the continued miniaturization in electronics to provide additional power, memory, and storage, and with a big change in sensor technology, these new breakers are a quantum leap ahead of their predecessors.

With the evolution of breaker trip units starting with basic overcurrent protection, you now have advanced capabilities that offer a host of additional protective functions nearly equal to functions offered by medium/high voltage multi-function relays. A few key features to look for include monitoring capabilities such as voltage, power quality, and even temperature of external sensors connected to the breaker.

Much of the new functionality is made possible by the replacement of the lower accuracy non-linear iron core current transformers with highly accurate linear current sensors. These sensors are based on the Rogowski coil concept. With traditional iron core current transformers, there is a tradeoff between measurement range and accuracy. Circuit breakers require sensing a large range of currents and accuracy is not as important. Today’s demands for metering require a smaller sensing range and much greater accuracy. The Rogowski coil sensor can cover a wide range of currents and has a very linear response. It is the perfect sensor for both protection and metering.

As mentioned, the real leap in value is moving so many functions “on board” the breaker trip unit that, in the past, could only be delivered by purchasing, integrating, and programming separate devices. A few examples (many more to explore) include:

• Built in programmable logic – Moves functions formerly available only through the addition of one or more PLCs, such as automatic source transfer, load shedding, load control, and generator control
• Communications – Standard network connections, additional communications technology such as IEC6185/GOOSE to high-speed breaker to breaker communications and coordination, including serving as a bridge between LV/MV applications.
• Metering – Ability to delivery revenue-class metering (typically 1% accuracy), harmonic measurement and reporting, and power quality monitoring
• Commissioning – Allows direct access to trip units via HMI panel (one panel for multiple breakers), or USB device (just copy over the settings), or even Bluetooth connection (outside the arc-flash zone)

The Evolution Will Certainly Continue

We’ve touched on the evolution of the circuit breaker trip unit across a century. Generally, three key technical advancements have opened up the possibilities of today’s advanced circuit protection with a molded case breaker – increased processor power (intelligence) due to advances in circuit board/component miniaturization, increased sensor accuracy as advances allowed for the application of the Rogowski coil for linear measurement, and the continued improvements to high-speed communications both in the processor capabilities and communication protocols. Overall, these three things combine to deliver the key cornerstone values required in smarter, safer, and more reliable power – accuracy plus the ability to make decisions and execute responses in milliseconds.

These capabilities will continue to evolve, and you and your customers will continue to benefit from the advancement of cheaper and more available raw computing power and communications over time.

• Friedel, R., & Israel, P. (1987). Edison’s electric light biography of an invention. New Brunswick, NJ, NJ: Rutgers Univ. Pr.
• Riemensperger, S. (2014, October 31). Miniature Breakers Stop Overloads, Short Circuits. Retrieved July 22, 2020, from com/conversations
• Electrical installation handbook – Protection, control and electrical devices (Sixth ed., ABB Technical Guide). (2010). Bergamo Italy: ABB SACE.
• Figure 3 – 3. (n.d.). In A Working Manual on Molded Case Circuit Breakers (Third ed.). Beaver, PA: Westinghouse Electric Corporation

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Success! Subscription added.

Success! Subscription removed.

Sorry, you must verify to complete this action. Please click the verification link in your email. You may re-send via your profile .

• Intel Community
• Product Support Forums

Processor Thermal Trip

• Subscribe to RSS Feed
• Mark Topic as New
• Mark Topic as Read
• Float this Topic for Current User
• Printer Friendly Page

• Mark as New
• Report Inappropriate Content
• Intel® Q87Q85 Chipset

View solution in original post

• All forum topics
• Previous topic

Link Copied

Community support is provided Monday to Friday. Other contact methods are available here .

Intel does not verify all solutions, including but not limited to any file transfers that may appear in this community. Accordingly, Intel disclaims all express and implied warranties, including without limitation, the implied warranties of merchantability, fitness for a particular purpose, and non-infringement, as well as any warranty arising from course of performance, course of dealing, or usage in trade.

For more complete information about compiler optimizations, see our Optimization Notice .

• ©Intel Corporation
• Terms of Use
• *Trademarks
• Supply Chain Transparency

Thermal trip

A device which is operated by a rise in temperature. It is used on circuit breakers, relays, etc., and is often a bimetallic strip which deflects when heated.

Related content

• Privacy notice
• Cookie notice
• Terms of Use

https://www.rockwellautomation.com/en-us/products/details.140G-H3F3-D12-SD.html

Molded Case Ckt-Bkr, 125A H Frame, 35 kA at 480V, T/M - Adjst Thrm / Adjst Mgntc, 3 Poles, 125A, 80 Percent MCCB, No Bus Bar Mounting, None, 110...120V AC/DC, Shunt open release, None

Learn how  to avoid the risks of unauthorized and counterfeit products.

• Project Project Find Product Drawings
• Bill of Materials My Bill of Materials Add to BoM
• Support Support Get Support
• Specifications

Documentation

Technical specifications, construction, environmental.

• Social Media Cookies
• Functional Cookies
• Performance Cookies
• Marketing Cookies
• All Cookies

• Circuit Breakers
• Connecticut Electric
• Crouse-Hinds Cooper
• Eaton Cutler Hammer
• Federal Pacific
• Thomas Betts
• Westinghouse

Motor Controls

• Allen Bradley
• Appleton Electric
• Cutler Hammer
• E.M. & Wiegmann
• Joslyn Clark
• Killark Electric
• Moeller Electric
• NSI Industries

Transformers

• Dongan Electric
• Hammond Power

Absolutely Everything You Need to Know About a Thermal Magnetic Circuit Breaker

• 24 Jan, 2018
• Posted by: Circuit Breaker Wholesale

Do you know how a thermal magnetic circuit breaker works?

If not, it’s worth finding out as these popular options are probably going to be the best bet for your home or building.

How a Thermal Magnetic Circuit Breaker Works

Despite the name, it’s actually fairly easy to understand how a thermal magnetic circuit breaker works. You just have to understand how two other versions operate first.

How a Magnetic Circuit Breaker Works

The main difference between these two circuit breakers comes down to what makes them trip. In other words, the difference is in how they protect the home/building’s wiring.

In a magnetic circuit breaker , this is done with an electromagnet.

When an acceptable amount of current is throwing through the breaker, the electromagnet is unaffected. It’s calibrated to move the trip bar when sufficient magnetic force – via a strong enough current – is present.

As the current increases through the coil, it could eventually reach a threshold where it becomes powerful enough to pull the trip bar toward the electromagnet. This would open the contacts and stop the current.

In doing so, it prevents significant damage from occurring – including a fire.

Magnetic circuit breakers shut down immediately when the current becomes too powerful. The moment the magnetic current becomes strong enough, it automatically pulls the trip bar.

How a Thermal Circuit Breaker Works

A thermal circuit breaker accomplishes the same thing by using a bimetallic strip.

Again, as the current builds in power, it becomes hotter and hotter.

At some point, the temperature reaches a predetermined threshold for the breaker and actually damages the bimetallic strip to the point that it gives and breaks the connection.

Fortunately, when it cools down, the strip is able to be reset and normal operation can continue.

Unlike the magnetic version, a thermal circuit breaker works on a time delay. The heat must build until it is able to deform the strip enough to shut down operation.

As the name suggests, a thermal magnetic circuit breaker works by combining the two versions above.

It essentially leverages both forms to protect the conductors and other elements connected to the circuit breaker from the dangers of excessive current.

The main advantage of how a thermal magnetic circuit breaker works is that it gives you both instantaneous and time-delayed protection.

Instantaneous protection is good for interrupting currents that are extremely powerful but not part of normal operation, like line-line faults, line-ground faults, and short circuits. They must be interrupted right away or they could become dangerous, even fatal.

So why would you ever want a delayed response?

Some pieces of electrical equipment temporarily draw currents that exceed their rated values. This is part of their normal operation. Examples of this type of equipment include electric motors and HID lamps.

When started, they can pull extremely high inrush currents.

A magnetic circuit breaker would not allow this initial requirement, so these devices wouldn’t work.

Choose a Thermal Magnetic Circuit Breaker

The advantages of relying on a thermal magnetic circuit breaker should be fairly obvious. In short, they will keep your home or building safe without limiting the types of devices you can use. Given their popularity, you’ll also have no problem finding one that fits your unique needs.

Thermal-Magnetic Trip Unit Summary

Introduction

Thermal-magnetic trip units are designed to provide protection for distribution or for specific applications.

The following table shows the trip units compatible with the Compact NSX circuit breakers. For more information, refer to Compact NSX & NSXm Catalogue .

Protections and Settings of Thermal-Magnetic Trip Units

The adjustment dials are on the front of the trip units:

Upgradeability of Thermal-Magnetic Trip Units

Upgradeability of trip units depends on the circuit breaker type:

o For 1 or 2 poles, trip units are built-in.

o For 3 or 4 poles, trip units are interchangeable.

NOTE: In Compact NSX circuit breakers with R, HB1, and HB2 breaking performances, the trip units are not interchangeable.

Onsite swapping of trip units is simple and reliable:

o No connections to make

o No special tools (for example, calibrated torque wrench)

o Compatibility of trip units provided by mechanical cap

o Torque limited screw provides proper mounting (see drawing below)

The design of the trip units limits the risk of incorrect tightening or oversights. The simplicity of the swapping process means that it is easy to make the necessary adjustments as operation and maintenance processes evolve.

NOTE: When the trip unit has been mounted by this means, the trip unit can still be removed: the screw head is accessible. When a trip unit is reinstalled after being removed, it is mandatory to use torque limiting snap-off screws LV429513 for the reinstallation.

Sealing the Protection

The transparent cover on thermal-magnetic trip units can be sealed to prevent modification of the protection settings:

DOCA0140EN-01

© 2020 Schneider Electric. All rights reserved.

• Car Rentals
• Airport Transfers
• Attractions & Tours
• Flight + Hotel
• Destinations
• Trip.com Rewards

【Hot Springs】Discover the Best Overseas Hot Spring Retreats

New Zealand: Discover the Enchanting Allure of Volcanic Geothermal Wonders

Iceland: a premier global wellness retreat, japan: a haven of hot springs, turkey: pamukkale's travertine hot springs, hungary: elegant historic bathhouses, south korea: explore the unique charm of rare carbonate hot springs, france: naturally isotonic thermal springs, switzerland: alpine hot springs, thailand: discover the mae kachan hot spring in chiang rai, united kingdom: discover the roman baths.

Show More 

Hot springs are rare resources gifted by nature. Hot springs vary widely around the world due to the influence of topography, geology and other conditions. This article takes a look at the amazing hot spring resorts in 10 countries around the world. Each hot spring presents a unique charm.

Discover the Geothermal Wonders of Rotorua's Hot Springs

Are you familiar with New Zealand's renowned hot spring capital? Rotorua is an industrial city situated in the central northern part of New Zealand's North Island. Situated on the southern shore of Lake Rotorua and more than 200 kilometers from Auckland, this city is celebrated for its abundant natural hot springs. It serves as a home to the Māori people and is a well-known tourist hotspot. Positioned in a region with vigorous volcanic activity, Rotorua boasts a wealth of hot springs, giving the city's air a distinctive sulfuric scent. Rotorua stands out as a magnificent natural tourist haven across the entire South Pacific.

Waiotapu Enchanted Geothermal Wonderland: A Spectrum of Geothermal Beauty

Features: Wai-o-Tapu, which translates to "Sacred Waters" in Maori, is one of Rotorua, New Zealand's most famous geothermal areas. The Wai-o-Tapu Geothermal Park, formed by volcanic activity over thousands of years, is renowned for being New Zealand's most colorful and diverse geothermal landscape, featuring boiling mud pools, mineral terraces, and geysers. The park, often enveloped in mist, feels like a surreal fairyland. Its most iconic attractions are the beautiful Champagne Pool and the Lady Knox Geyser, which erupts at around 10 AM each day.

Location: 201 Waiotapu Loop Road, Rotorua 3073, New Zealand

Blue Lagoon Hot Springs: "A Natural Beauty Spa"

Feature: Nestled in Grindavík on the Reykjanes Peninsula of southwestern Iceland, the Blue Lagoon is a geothermal hot spring created by volcanic lava. The waters, abundant in minerals such as silicon and sulfur, bestow the lagoon with its enchanting blue color. The natural geothermal energy from beneath the earth ensures that the lagoon remains invitingly warm all year round. A favorite among locals since the 1970s, the Blue Lagoon offers a unique experience. While enjoying the warm embrace of the waters, don't miss out on applying the silica mud to your face. This volcanic mud, laden with minerals, makes for an excellent natural face mask.

Location: 9 Norðurljósavegur, Grindavík 240, Iceland

Sky Lagoon: The Convergence of Ocean and Sky

Feature: Sky Lagoon, nestled about 7 kilometers south of downtown Reykjavik in southwestern Iceland. As you enter the Sky Lagoon hot spring pool, you're immediately enveloped in steam that seems straight out of a fairy tale. Perched on the edge of the ocean, the pool is fittingly named "Where the ocean meets the sky," providing panoramic views of the vast coastline. It's an ideal spot for catching the mesmerizing Northern Lights in the winter or basking in Iceland's distinctive midnight sun during the summer months.

Location: 44-48 Vesturvör, Suite 200, Kópavogur, Iceland

Arima Onsen

Highlights: Nestled in Arima, Kita Ward of Kobe, Hyogo Prefecture, Arima Onsen stands as one of the oldest hot springs in the Kansai region, often celebrated as "the cultural heartland of Kobe." This historic hot spring, part of Japan's trio of famed springs alongside Gero Onsen and Kusatsu Onsen, boasts a storied history of 1300 years. Surrounded by mountains on three sides, Arima Onsen offers seasonal delights with cherry blossoms in spring and fiery maple foliage in autumn, making it a beloved retreat for visitors. Immersing in its warm, soothing waters, one can enjoy the serene interplay of steam and the ethereal mountain mists.

Location: Kita Ward, Kobe, Hyogo 651-1401

Explore Beppu Onsen in Oita Prefecture

Beppu Onsen: Renowned for the "Beppu Eight Hot Springs"

Highlights: Beppu Onsen, nestled on the southwestern shores of Japan's Kyushu Island, is celebrated for its vibrant geothermal activity, featuring dramatic eruptions from areas famously dubbed as "Hell." Renowned for the "Eight Hot Springs," also known as the "Eight Hells of Beppu," this region includes the distinct hot spring towns of Beppu, Myoban, Kannawa, Horita, Shibaseki, Kamegawa, and Hamawaki. Each offering its own unique features and a variety of therapeutic options, including milk baths, sand baths, and mud baths.

Beppu Onsen Located at 16-23 Motomachi, Beppu, in Ōita Prefecture, this site is nestled in one of Japan's most famous hot spring destinations, renowned for its rich variety of thermal baths.

Noboribetsu Hot Spring Town: Hokkaido's Top Hot Spring Retreat

Highlights: Noboribetsu Hot Spring Town stands as a prominent hot spring destination in Hokkaido, encircled by mountains. The town is lined with an assortment of hot spring hotels, inns, and a variety of restaurants. Attractions close by include Hell Valley, Oyunuma, and Noboribetsu Bear Park. With its extensive selection of hot springs, featuring more than a dozen different water qualities, the town offers a unique experience. Bathing in an open-air hot spring during a snowy winter day provides an exceptionally romantic and cozy atmosphere.

Location: Noboribetsu City Hokkaido Noboribetsu Onsen Town

Travertines of Pamukkale: Celebrated as One of the World's Seven Wonders

Features: Tucked away in the Denizli Province of southwestern Türkiye, the Travertines of Pamukkale are famed for their striking resemblance to a pristine, snow-white castle and have captivated visitors worldwide. These thermal springs, with a history spanning thousands of years, feature jade-like, semi-circular white terraces that cascade beautifully one atop another. Delicate streams trickle through the hillside crevices, while warm vapors cloak the area in a soft, mystical fog.

Location: Merkez, 20190 Pamukkale/Denizli, Turkey

Széchenyi Thermal Bath: A Blend of Splendor and Nostalgia

Features: Budapest, celebrated as a historic European city, is also distinguished as a unique metropolis of hot springs. The city is dotted with numerous thermal baths, originally developed by the bath-loving ancient Romans over 2000 years ago. These springs, known locally as 'Furdo'—the Hungarian term for 'bath,' attract countless visitors from home and abroad. Nestled within the city park, the Széchenyi Thermal Bath is a highlight among Budapest's thermal offerings. With its sophisticated architectural design and springs encircled by a courtyard, it embodies a timeless classical elegance.

Location: Zoo Boulevard 9-11, Budapest 1146, Hungary

Thermal Lake of Hévíz: Abundant in Therapeutic Humic Peat Mud

Features: Nestled in the serene town of Hévíz, the Thermal Lake of Hévíz is celebrated for its biologically vibrant natural hot spring lake, a jewel of national pride. It stands as one of Europe's largest warm water hot spring lakes and is the world's second-largest by area. Given its depth, bathers are required to wear life rings. With roots stretching back to the Roman era, this hot spring lake has become a distinguished landmark in the Lake Balaton region.

Location: 1 Dr. Vilmos Schulhoff Street, Hévíz, 8380, Hungary

Sanbangsan Mountain Carbonate Hot Springs: A Haven of High-Quality Carbonate Waters

Features: Tucked away on Jeju Island, cradled by the trio of Marado, Gapado, and Brothers Islands, along with the quintet of mountains—Hallasan, Sanbangsan, Gunsan, Songaksan, and Dansan—Sanbangsan Mountain Carbonate Hot Springs emerges as one of South Korea's pioneering public hot springs. Celebrated for its unique carbonate waters, rich in therapeutic benefits, it was designated in 2004 as a World Hot Spring Source Protection Area, underscoring its global ecological and cultural importance.

Location: 192 Sagyebuk-ro 41beon-gil, Andeok-myeon, Seogwipo-si, Jeju-do

Les Thermes evian: Alpine Natural Mineral Springs

Features: Nestled behind Evian Town, the towering Alps are the origin of the renowned Evian water, derived from the meltwater of high mountains and rainfall. This pristine water is naturally filtered over 15 years through the depths of the Alps and enriched with minerals from glacial sands. It is this very spring water that ensures the French ladies who frequent these hot springs are left spotless and radiant, securing the French hot springs' title as the "Queen among spa cities."

Location: Liberation Square, Post Box 8, 74501 EVIAN-les-BAINS Cedex, France

Alpentherme: Soak in Hot Springs with Snowy Mountain Views

Highlight: The Loèche-les-Bains Thermal Center stands as a distinguished spa and wellness retreat in Switzerland. With roots stretching back to the Roman era, this spa city has welcomed historical luminaries like Goethe, Maupassant, and Wimpfen. It boasts the contemporary Alpentherme, perched at an elevation of approximately 2000 meters, and offers outdoor hot springs nestled amidst breathtaking snow-capped mountains.

Location: Dorfplatz, CH-3954 Leukerbad

Mae Kachan Hot Spring: Experience the Unique Sulfur Springs Where You Can Boil Eggs

Highlights: Chiang Rai boasts a remarkable array of hot spring pools, mainly sulfur springs, renowned for their intense heat, comparable to boiling springs. Guests can enjoy complimentary activities such as foot soaking or egg boiling in selected pools. Close to the entrance, a geyser spectacularly erupts every 7 seconds, sending a jet of water soaring into the air.

Location: 4F76+WV8 Moo 6 Pha Soet Phatthana Village Doi Hang Chang Wat Chiang Rai 57260, Thailand

The Roman Baths: Surrounded by this street, which is known as "the most noble and elegant street in Britain", there is an ancient Roman thermal bath with a history of 2,000 years. The city of Bath got its name from this. Under the bath, you can still see the spring water gushing out, flowing into the bath along the ancient channel and finally flowing into the river.

Location: Abbey Churchyard, Bath BA1 1LZ, United Kingdom

>>>Japan Fireworks Festival Guide 2024 | Get Info on the Dates, Locations and Transport

Trending Travelogues

Popular travel types, popular attractions, popular ranked lists, popular destinations, recommended attractions at popular destinations.

• Customer Support
• Service Guarantee
• More Service Info

• About Trip.com
• Terms & Conditions
• Privacy Statement
• About Trip.com Group

Other Services

• Investor Relations
• Affiliate Program
• List Your Property
• Become a Supplier

• Özel ürün araçları ve hizmetler edinin
• Eğitime erişin
• Destek vakalarını yönetin
• Siparişlerinizi oluşturun ve yönetin (yalnızca yetkili iş ortakları)

Schneider Electric Web Sitesine Hoş Geldiniz

Ticarileştirmenin sona ermesi, Schneider Electric'in bu referans için teklif kabul edeceği son gün anlamına gelir. Ancak, Satış Sonrası Hizmetler (onarım, yedek parçalar vb.) kullanım ömrü sonuna kadar devam edecektir.

Ülkenizdeki günün 24 saati hizmet veren Müşteri Hizmetleri Merkezi ile iletişime geçin.

Circuit breaker EasyPact CVS630F/N/H, 36/50/70 kA at 415VAC, 630 A rating thermal magnetic TM-D trip unit, 3P 3d