an electronic trip unit

Micrologic 4 Electronic Trip Units

Introduction

The Micrologic 4 electronic trip unit is designed to protect:

o Conductors in commercial and industrial electrical distribution.

o Goods and people in commercial and industrial electrical distribution.

On 4-pole circuit breakers, neutral protection is set on the Micrologic trip unit by using a three-position dial:

o 4P 3D: neutral unprotected

o 4P 3D + N/2: neutral protection at half the value of the phase pickup, 0.5 x Ir (not available on Micrologic trip unit with In ≤ 40 A)

o 4P 4D: neutral fully protected at Ir

The Micrologic 4 electronic trip unit is available in two versions for earth-leakage detection:

o The Trip version trips when earth-leakage is detected.

o The Alarm version measures the earth-leakage current and indicates an earth-leakage fault on the front face with the earth-leakage fault indicator, which changes from gray to yellow.

When the SDx indication contact is present, it signals an earth-leakage fault remotely.

Description

The adjustment dials and indications are on the front face.

The trip unit rating In corresponds to the maximum value of the setting range.

Setting the Long-Time Protection

The long-time protection pickup Ir is set by using two multi-position dials.

o The preset dial allows the pickup to be preset to the value Io (displayed in amperes on the dial).

The maximum preset value (maximum setting on preset dial) equals the trip unit rating value In.

o The adjustment dial can be used to fine-tune the pickup Ir (value displayed in multiples of Io on the dial).

The time delay tr for long-time protection cannot be adjusted.

The following table shows the value of the time delay tr for long-time protection (in seconds) according to the overload current (in multiples of Ir)

The precision range is -20%, +0%.

Setting the Short-Time Protection

The short-time protection pickup Isd is set by using a multi-position dial.

The setting value is expressed in multiples of Ir.

The precision range is +/- 15%.

The time delay tr for short-time protection cannot be adjusted:

o Non-trip time: 20 ms

o Maximum breaking time: 80 ms.

Setting the Instantaneous Protection

The pickup Ii for instantaneous protection cannot be adjusted.

The following table shows the value of the pickup Ii for instantaneous protection (in amperes) according to the trip unit rating In:

The time delay for instantaneous protection cannot be adjusted:

o Non-trip time: 0 ms

o Maximum breaking time: 50 ms.

Setting the Neutral Protection (4P Only)

The neutral selection dial gives a choice of three values for the neutral long-time and short-time protection pickups.

The following table shows the values of the pickup for neutral long-time protection (in multiples of Ir) and neutral short-time protection (in multiples of Isd) according to the dial position:

The time delay for the neutral long-time protection and short-time protection is the same as that for the phases.

Setting the Earth-Leakage Protection

The earth-leakage protection IΔn, type A, is set by using a multi-position dial.

The following table shows the value of the pickup IΔn for earth-leakage protection according to the trip unit rating In:

The OFF setting annuls any earth-leakage protection and the circuit breaker behaves as a standard circuit breaker for cable protection.

Setting the earth-leakage protection to OFF can be used to inhibit earth-leakage protection during periods of setting, commissioning, testing and maintenance.

Setting the Earth-Leakage Protection Time Delay

The time delay of the earth-leakage protection is set by using a multi-position dial.

When IΔn is set to 30 mA, the time delay Δt is always 0 ms regardless of the position of the dial (instantaneous tripping).

When IΔn is set above 30 mA, the time delay Δt can be adjusted to the following values:

o 0 ms

o 60 ms

o 150 ms

o 500 ms

o 1000 ms

Testing the Earth-Leakage Protection

The earth-leakage protection must be tested regularly by using the test button ( T ). Pressing the test button simulates a real leakage current passing through the toroid, and the earth-leakage fault indicator displays the following symbol:

When the earth-leakage protection pickup IΔn is set to the OFF  position, pressing the test button has no effect.

In the case of the Trip version of Micrologic 4, pressing the test button trips the circuit breaker.

In the case of the Alarm version of Micrologic 4, pressing the test button causes the earth-leakage indicator to change to yellow.

If the circuit breaker does not trip, or the earth-leakage indicator does not change to yellow, check that the circuit breaker is energized. If the circuit breaker is energized correctly, and has not tripped or indicated the earth-leakage fault, replace the Micrologic 4 trip unit.

Resetting the Circuit Breaker After an Earth-leakage Fault Trip

Resetting the circuit breaker after an earth-leakage fault trip depends on the version:

o For the Trip version, reset the circuit breaker by moving the handle from Trip  to O (OFF)  position, and then to I (ON) position.

o For the Alarm version, press the test button ( T ) for three seconds.

For Trip and Alarm versions, the earth-leakage fault indicator changes back to gray after the reset.

Examples of Setting the Long-Time Protection

Example 1: Setting the long-time protection pickup Ir to 140 A on a Micrologic 4.2 trip unit rated In 250 A:

Example 2: Setting the long-time protection pickup Ir to 133 A on a Micrologic 4.2 trip unit rated In 250 A:

The actions in steps (2) and (3) on the adjustment dials modify the trip curves as shown:

Example of Setting the Short-Time Protection

Setting the short-time protection pickup Isd to 400 A on a Micrologic 4.2 rated In 250 A on a 133 A feed:

The action in step (2) on the adjustment dial modifies the trip curve as shown:

Example of Setting the Earth-Leakage Protection

Setting the earth-leakage protection pickup IΔn to 1 A with a tripping time delay of 500 ms on a Micrologic 4.2 rated In 250 A:

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Characteristics of MicroLogic Electronic Trip Units

• MicroLogic 2 Electronic Trip Units
• MicroLogic 4 Electronic Trip Units
• MicroLogic 1.3 M Electronic Trip Unit
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• MicroLogic 2 G Electronic Trip Unit
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• ComPact NSX 100-250 - Distribution Protection Tripping Curves
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• ComPact NSX 400-630 - Distribution Protection Tripping Curves
• ComPact NSX 400-630 - Motor-Feeder Protection Tripping Curves
• ComPact NSX 100-630 - Reflex Tripping
• ComPact NSX 100-630 - Limitation Curves

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Introduction

Protection of the electrical distribution or specific applications

Measurement of instantaneous values and measurement of average values (demand) for electrical quantities

Kilowatt hour metering

Operational assistance such as peak demand, customized alarms, and operation counters

Communication

Identification

Identify the trip unit installed on the circuit breaker by using the four characters on the front face:

MicroLogic Trip Unit Families

MicroLogic 1 , 2 , and 4 without display screen

MicroLogic 5 , 6 , and 7 with display screen.

By using the adjustment dials

By additional settings on the keypad. Setting values are displayed on the screen

Through EcoStruxure Power Commission software.

For more information about the MicroLogic 5 , 6 , and 7 trip units, refer to DOCA0141EN , ComPact NSX MicroLogic 5/6/7 Electronic Trip Units - User Guide .

In Rating of MicroLogic Trip Units

The In rating (in amps) of a MicroLogic trip unit corresponds to the maximum value of the long-time protection ( Ir ) setting range for the trip unit. The setting range is indicated on the label on the front face of the trip unit (this label is visible on the front face of the ComPact NSX circuit breaker after the trip unit has been fitted).

Setting range: 100-250 A

In rating = 250 A

Distribution Trip Unit

The following figure and table define the protection functions for distribution-type MicroLogic trip units.

Thermal Memory

The thermal memory is used to simulate temperature build-up and cooling in conductors caused by current variations, according to a time constant. In the event of an overload, the trip units with a thermal memory memorize the build-up temperature caused by the current. Memorizing the build-up temperature leads to a reduction in the trip time.

For MicroLogic 2 and 4 trip units, the time constant is 15 minutes.

For MicroLogic 5 , 6 , and 7 trip units, the time constant is 20 minutes.

Motor Trip Units

The following figure and table define the protection functions for MicroLogic type M trip units.

Motor Trip Unit: Additional Protection

MicroLogic type M trip units (in particular MicroLogic 6 E-M ) also incorporate additional protection for the motor application. For more information, refer to DOCA0141EN , ComPact NSX MicroLogic 5/6/7 Electronic Trip Units - User Guide ..

Indication LEDs

Indication LEDs on the front of the trip unit indicate its operational state.

The LEDs and their meaning depend on the type of MicroLogic trip unit.

Above 15 A on a MicroLogic trip unit rated 40 A

Above 30 A on MicroLogic trip units rated > 40 A

The limit value is indicated on the front panel, above the Ready LED of the MicroLogic trip unit. NOTE: For the MicroLogic 4 and 7 trip units, the protection functions are supplied by a second power supply, in addition to the current transformer supply. The Ready LED blinks irrespective of the load, indicating that the standard protection functions are operational.

Install a 24 Vdc external power supply module which allows the trip unit to be monitored continuously, even when the circuit breaker is open. For more information, refer to LVPED217032EN , ComPact NSX & NSXm Catalogue .

Or, during maintenance visits, connect the pocket battery to monitor the trip unit.

MicroLogic trip units feature a test port specifically for maintenance actions .

Use the test port to:

Connect a pocket battery for local testing of the MicroLogic trip unit

Connect the Service Interface for testing, setting the MicroLogic trip unit, updating the MicroLogic firmware, or for installation diagnostics with EcoStruxure Power Commission software

For push-to-trip test or installation diagnostics with the USB maintenance interface stand-alone

For testing and installation diagnostics, setting the MicroLogic trip unit, updating the MicroLogic firmware with the USB maintenance interface connected to a PC

Interchangeability of MicroLogic Trip Units

No connections to make

No specific tools (for example, calibrated torque wrench)

Compatibility of trip units provided by mechanical cap

Torque limited screw provides correct torque

The simplicity of the replacement process means that it is easy to make the necessary adjustments as operation and maintenance processes evolve. NOTE: The screw head is accessible when the trip unit is installed, so the trip unit can still be removed. NOTE: On ComPact NSX circuit breakers with NA , R , HB1 , HB2 , and K breaking performances the trip units are not interchangeable.

Sealing the Protection

Seal the transparent cover on MicroLogic trip units to prevent modification of the protection.

On MicroLogic 5 , 6 , and 7 trip units, it is possible to use the keypad, with the cover sealed, to read the protection settings and measurements.

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Electronic Trip Circuit Breaker Basics: Schneider Electric Micrologic Trip Units

What is electronic trip circuit breakers .

An electronic trip circuit breaker is a type of circuit breaker that uses electronic components to control the tripping mechanism instead of traditional thermal-magnetic trip elements. Electronic trip circuit breakers are commonly used in industrial and commercial applications where high reliability and selective coordination are required.

These circuit breakers use a solid-state trip unit to sense and respond to overcurrent conditions. The trip unit monitors the current flowing through the circuit breaker and can be programmed to trip at specific current levels and time delays. This allows for greater precision in protecting against overcurrent conditions and reduces the risk of nuisance trips. Electronic trip circuit breakers can also provide advanced monitoring and diagnostic capabilities. Some models can provide real-time current and voltage measurements, as well as fault event recording and reporting. This information can be used to identify potential issues and optimize system performance.

Related Article:  Circuit Breaker Essentials 

Why Use Electronic Trip Circuit Breakers? 

In most cases, the basic overcurrent protection provided by standard thermal-magnetic circuit breakers will meet the requirements of the electrical system design. In some cases, however, basic overcurrent protection might not be enough. Electronic trip circuit breakers can provide the additional features needed in those cases.

Reasons to use electronic trip circuit breakers includes:

• Enhanced coordination capabilities
• Integral ground-fault detection
• Communication capabilities
• Future growth potential

Enhanced Coordination Capabilities

Schneider electric micrologic electronic trip units.

• Independent adjustments  - allow one dial setting to be changed without affecting the rest of the pickup and delay levels. This allows the designer to better define the tripping characteristics needed on the system. 
• Interchangeable rating plugs-  allow the designer to shift the entire trip characteristic curve (except for ground fault) to improve coordination with other devices. MICROLOGIC rating plugs define the circuit breaker's maximum current rating based on a percentage of the circuit breaker sensor size and can be used on any frame size of circuit breaker within the MICROLOGIC family of circuit breakers. 
• Withstand ratings give the designer a larger window of coordination potential - The withstand rating is the level of rms symmetrical current that a circuit breaker can carry with the contacts in the closed position for a certain period of time. At current levels above the withstand rating (and less than or equal to the interrupting rating), the circuit breaker will trip instantaneously. In other words, the withstand rating is the highest current level at which delay can be introduced to maintain coordination with downstream devices. Withstand ratings are available only on full-function trip systems ordered with the adjustable short-time function.
• Inverse time delay characteristics  - allow for better coordination with fusible switches or thermal-magnetic circuit breakers downstream. Devices that respond to heat generated by current flow (such as fuses and thermal-magnetic circuit breakers) have inverse time tripping characteristics. This means that as current increases, the time that it takes the device to trip will decrease. In order to coordinate better with these types of downstream devices, MICROLOGIC circuit breakers offer inverse time delay characteristics on the long-time, short time and ground-fault functions. 
• Ammeter/trip indicator - displays the level of ground-fault leakage current associated with the circuit. The ground-fault pickup level on the circuit breaker may then be adjusted somewhat higher than the amount of leakage current displayed on the ammeter.

Integral Ground Fault Protection

Communication capabilities.

• History of last trip
• Trip unit pickup and delay levels
• Impending trip conditions
• Operating currents for each phase
• Ground-fault leakage current associated with the circuit
• Ground-fault alarm signal

Standard Function Trip Unit Curves

Long term trip function.

• LONG-TIME PICKUP Switch — switch value (multiplied by the ampere rating) sets the maximum current level which the circuit breaker will carry continuously. If the current exceeds this value for longer than the set delay time, the circuit breaker will trip. 
• LONG-TIME DELAY Switch — sets length of time that the circuit breaker will carry a sustained overload before tripping. Delay bands are labeled in seconds of overcurrent at six times the ampere rating. For maximum coordination, eight delay bands are available.

Short-time Trip Function

• SHORT-TIME PICKUP Switch — switch value (multiplied by the ampere rating) sets the short-circuit current level at which the circuit breaker will trip after the set SHORT-TIME DELAY.
• SHORT-TIME DELAY Switch — sets length of time the circuit breaker will carry a short circuit within the short-time pickup range. Delay bands are labeled in seconds of short-circuit current at 12 times the ampere rating, P. The short-time delay can be set to one of four I^2t ramp operation positions (I^2t IN).

Instantaneous Trip Function

• INSTANTANEOUS PICKUP Switch — switch value (multiplied by the ampere rating) sets the short-circuit current level at which the circuit breaker will trip with no intentional time delay. The instantaneous function will override the short-time function if the INSTANTANEOUS PICKUP is adjusted at the same or lower setting than the SHORT-TIME PICKUP. 
• GROUND-FAULT PICKUP Switch — switch value (multiplied by the sensor size) sets the current level at which the circuit breaker will trip after the set GROUND-FAULT DELAY.
• GROUND-FAULT DELAY Switch — sets the length of time the circuit breaker will carry ground-fault current which exceeds the GROUND-FAULT PICKUP level before tripping. Delay bands are labeled in seconds of ground-fault current at 1 times the sensor size, S. Ground-fault delay can be adjusted to one of four fixed time delay positions (I^2t OUT). 

In Comparison with Thermal Magnetic Circuit Breakers

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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

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SACE Tmax T

A complete range of moulded case circuit-breakers up to 3200 a..

All the circuit-breakers, both three-pole and four-pole, are available in the fixed version; sizes T4 and T5 in the plug-in version and T4, T5, T6, and T7 also in the withdrawable one.

High breaking capacity in compact dimensions High values of short circuit breaking capacity are guaranteed at different voltage levels, without compromising overall dimensions.

Flexibility of use Thermomagnetic and electronic trip units are available for use in AC/DC or in AC only. It is possible to interchange trip units keeping the same breaking part, so that installation can be upgraded with fewer costs.

Advanced protection A complete range of electronic trip units is suitable for different level of protection, even enhancing selectivity values with Early Fault Detection and Prevention algorithm.

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To extend the warranty of ABB Low Voltage Circuit Breakers, ABB extends the warranty to customers in addition to the standard warranty by: +1 year (free of charge) and/or +3 years  on • new equipment  • purchased products (within factory standard warranty time=12months)  

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Product offering

For applications in accordance to IEC 60947-2 Standard

For applications in accordance to UL 489 and CSA C22.2 Standard

For applications up to 1500V DC and 1150V AC

For variable frequency applications

Low-voltage, shockproof circuit breakers

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Applications, certifications, product software, multimedia applications, power distribution.

The most common application for moulded case circuit breakers is power distribution. SACE Tmax T4 T5, T6, T7 and T8 are available with thermomagnetic and electronic trip units to fit the needs.

TMA trip units are an option for Tmax T4, T5 and T6 up to 800A, while a wide range of electronic trip units is able to support a better customization of the protection functions:

• PR221DS: basic trip units for standard applications on Tmax T4, T5 and T6
• PR231/P and PR232/P: basic trip units for standard applications on Tmax T7 and T8
• PR222DS/P: advanced trip units on Tmax T4, T5 and T6 with more options to adjust protection functions thresholds, even electronically. Ground fault protection and MODBUS network upgrade are available.
• PR331/P and PR332/P: advanced trip units for Tmax T7 and T8. Ground fault protection and MODBUS network upgrade on PR332/P are available.

Energy metering

During the last years, the growing attention to the environmental issues together with new policies of cost reduction, which involve not only capital costs but also operational costs, has led to a wider diffusion of the energy measurements practice down to the lower distribution levels.

Aim of this tendency is to get to an optimal load management and to identify possible system inefficiencies. Examples of these loads can be machinery, any subparts of an industrial plant, the various modules that compose a data center as well as the different consumptions of a conditioning system in a mall. The possibility to measure, transmit and store data about each load is fundamental.

PR223DS is the solution for energy metering for Tmax T4, T5 and T6 in conjunction with voltage module VM210. Tmax T7 and T8 with PR332/P trip units and PR330/V are the answer for the same application for currents up to 1600A and 3200A. Mentioned trip units have an option to be integrated in a communication network.

Motor protection

Motor protection is one of the most common application for moulded case circuit breakers in low voltage installations.

Safety and reliability of solution are important aspects that must be considered when choosing and manufacturing a system for starting and monitoring motors. Start-up is a particularly critical phase for the motor itself and for the installation powering it.

When it comes to direct starting, ABB SACE proposes two different solutions:

• a conventional system with three poles circuit breaker equipped with a magnetic only trip unit for protection against short-circuits, a thermal relay for protection against overloads and phase failure or imbalance, and a contactor to operate the motor;
• an advanced protection system onboard the circuit breaker which integrates all the protection and monitoring functions, and a contactor for operating the motor

Tmax range offers both solutions thanks to its range of motor protection trip units.

PR221DS-I and PR231P-I trip units can be coordinated with contactors and thermal relays for the most common solutions.

Early Fault Detection and Prevention

Selectivity between protection devices in a low voltage installation is required in order to detect rapidly a fault and to isolate the fault zone so that all unaffected circuits can have service continuity.

Use of PR223EF electronic release is a way of realizing zone selectivity between Tmax T4L, T5L and T6L moulded case circuit breakers. PR223EF implements the EFDP technology (Early Fault Detection and Prevention), capable of detecting short-circuit by “predicting” the fault, based on analysis of the trend of the current derivative in relation to the time.

One of the main advantages in implementing EFDP technology and zone selectivity is the reduction in size of circuit breakers. By means of PR223EF releases, it is possible to obtain 100kA of selectivity even between two circuit breakers of the same size, so with no need to overdimension upstream device.

Certifications and Shipping Registers

SACE Tmax circuit breakers and accessories are designed, manufactured and tested in conformity with:

• IEC 60947-2 standard;
• EC “Low Voltage Directive” (LVD) N° 2006/95/EC
• EC “Electromagnetic Compatibility Directive” (EMC) 2004/108/CE
• main shipping registers such as Lloyd’s Register of Shipping, Germanischer Lloyd, Bureau Veritas, Rina, Det Norske Veritas, Russian Maritime Register of Shipping, ABS.

  ABB SACE Quality System conforms to following Standards:

• ISO 9001 international Standard;
• EN ISO 9001 (equivalent) European Standards;
• UNI EN ISO 9001 (equivalent) Italian Standards;
• IRIS International Railway Industry Standard.

ABB SACE Quality System obtained first certification with RINA certification body in 1990.

Attention to protection of the environment is a priority for ABB SACE. Confirmation of this is an Environmental Management System certified by RINA in conformity with the International ISO14001 Standard. In 1999 the Environmental Management System was integrated with the Occupational Health and Safety Management System according to the OHSAS 18001 Standard and later, in 2005, with the SA 8000 (Social Accountability 8000) Standard, committing itself to respect of business ethics and working conditions.

ISO 14001, 18001 and SA8000 recognitions together with ISO 9001 made it possible to obtain RINA Best Four Certification.

To explore the interface of ABB trip units, make a configuration, display the signals and conduct an operating simulation.

Instruction guides

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Electronic trip unit

The digitrip 210+ trip unit provides easy setup for coordination and reliable protection for electrical systems in commercial, industrial, and machinery manufacturing environments..

The Digitrip 210+ trip unit provides easy setup for coordination and reliable protection for electrical systems in commercial, industrial, and machinery manufacturing environments. Designed to fit FDE-frame molded-case circuit breakers, the trip unit offers electronic trip unit functionality in an economic platform. For installation in assemblies such as panelboards and switchboards, the 210 or more electronic trip units are available in LI and LSI. Both versions include a seven-position dial to set the current rating of the breaker. The LI includes an adjustable instantaneous protection setting. The LSI includes a short delay setting with magnitude and time-delay options to improve coordination when protecting against electrical faults in a system.

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This product is a Finalist in the Consulting-Specifying Engineer 2016 Product of the Year program. View more Finalists and cast your vote at www.csemag.com/votepoy (voting closes June 30, 2016).

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

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• Arc flash relay
• Arc-resistant switchgear

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Jason Isbell and the 400 Unit 2024 (Woodinville) | Chateau Ste Michelle Winery

Jason Isbell and the 400 Unit are set to grace the stage at the picturesque Chateau Ste Michelle Winery on July 16, 2024. Located at 14111 NE 145th Street, Woodinville, WA, 98072, this concert promises to be a night to remember. With a stellar setlist featuring hits like "Wichita Lineman," "Last of My Kind," "Cover Me Up," and more, attendees are in for a musical treat. Tickets for this highly anticipated event will be available for purchase from March 25, 2024, at 5:00 PM until July 17, 2024, at 4:00 AM. Don't miss the opportunity to experience the magic of Jason Isbell and the 400 Unit live in concert. Mark your calendars and secure your tickets early to ensure you don't miss out on this unforgettable evening of music and memories.

Provided by Chesapeake | Published Apr 11, 2024

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