motor protection circuit breaker

Save Your Motor from Overload and Short Circuit with TOSUNlux Motor Protection Circuit Breakers.

TOSUNlux MPCB breaker

Our Motor Protection Circuit Breaker (MPCB) is now officially certified with CE, CB, and UKCA!

TOSUNlux Motor Protection Circuit Breakers (MPCBs) provide reliable overload and short circuit protection for electric motors. These MPCBs, from the MP series, are designed for AC 50/60Hz circuits up to 660V and 0.1-80A. Our motor protection circuit breakers safely protect against short circuits, overloads and phase failures without the use of fuses. And our factory simplifies installation and wiring when assembling internal accessories, making it easy to use. MPCB ensures safe motor operation and minimizes downtime.
Choose TOSUNlux for superior motor protection.

MPCBs Collection

TOSUNlux offers a collection of motor circuit protectors to meet your needs for safe and reliable solutions.

MPCB AU auxiliary contact

Installation: Side (1PC on the right side of circuit breaker)

MPCB AE auxiliary contact

Installation: Front (1PC for each circuit breaker)

MPCB AD auxiliary contact

Fault signal contact+instantaneous auxiliary contact


Rated Standard Power of 3-phase; Motors 50/60Hz in category AC-3


Rated Standard Power of 3-phase Motors 50/60Hz in Category,AC-3

MP2-MC02 Waterproof box

MP Series Motor Protection Circuit Breaker

Why Choose TOSUNlux Brand?

Versatile Applications

TOSUNlux MP series MPCBs offer motor overload and short circuit protection within AC 50/60Hz circuits up to 660V, 0.1-80A power circuits and serve as full-voltage starters.

Adjustable Bimetallic Strip

TOSUNlux MPCBs have an adjustable bimetallic strip for precise overload protection with preset values of 40% and 100% of rated current.

Advanced Protection

Some TOSUNlux MPCBs feature phase loss or imbalance detection for three-phase motor systems.

Trusted Manufacturer

TOSUNlux is a reliable manufacturer and supplier of quality low voltage electrical and lighting products.

Comprehensive Guide

TOSUNlux provides a detailed MPCB guide covering definitions, types, functions, and applications.


TOSUNlux MPCBs offer superior, cost-effective motor protection, tripping up to 1000 times faster than fuses under overload conditions.

TOSUNlux: Your Reliable Solution for Motor Protection

TOSUNlux specializes in manufacturing and supplying low voltage electrical and lighting products. With their commitment to reliability, they offer trusted solutions to customers worldwide. TOSUNlux MPCBs provide dependable and efficient protection for electric motors against overload and overheating.

Quality and Certification

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All Your Questions

Here are some frequently asked questions about motor protection circuit breaker

A motor protection circuit breaker (MPCB) is an essential electrical device specifically designed to shield electric motors from potential harm resulting from excessive currents, voltage fluctuations, or electrical faults. MPCBs find extensive use across diverse industrial applications, including manufacturing plants, conveyor systems, pumps, compressors, and HVAC systems.

TOSUNlux MP series MPCBs serve multiple purposes, including overload and short circuit protection in AC 50/60Hz power circuits up to 660V, ranging from 0.1-80A. They function as full-voltage starters, facilitating motor startup and disconnection under AC3 load conditions. Furthermore, MPCBs ensure the safeguarding of circuits and power equipment in the distribution network by providing overload and short circuit protection.

The core functionalities of MPCBs comprise isolation, overload and short circuit protection for motors, and motor control (on/off). In the event of overcurrent or short circuit occurrences that may potentially damage the motor, MPCBs automatically disconnect the electrical circuits, averting any harm.

Advanced MPCBs go a step further by incorporating phase loss protection, preventing the motor from hazardous conditions such as excessive winding heat or even burning.

In summary, a motor protection circuit breaker is a specialized electrical device crucial for shielding electric motors against damage arising from excessive currents, voltage variations, or electrical faults. MPCBs are widely employed across diverse industrial applications, providing isolation, protection against overload and short circuit, and control over motor operations.

To guarantee the safe and efficient functioning of electric motors, it is crucial to select the appropriate motor protection circuit breaker (MPCB). Here are essential guidelines to aid your selection process:

1. Determine the total nameplate rated current of your motors, which represents the maximum operating current. Select an MPCB capable of handling this current to ensure effective protection.

2. Verify the nameplate voltage of the motor and choose an MPCB with a matching voltage rating. Various voltage options are available, such as 230V, 380V, 415V, 440V, 500V, and 660V AC.

3. Select an MPCB with a current rating that aligns with the motor’s nameplate current. Choosing an oversized MPCB may result in failure to detect over-current conditions, impeding motor startup. Optimal sizing is essential.

4. Consider the type of motor being protected. Advanced MPCBs offer additional features like phase loss or phase imbalance protection for three-phase motor systems.

5. Verify that the wire connecting the MPCB to the motor can safely conduct the rated current. Undersized wires risk overheating, insulation melting, and electrical faults, even if the MPCB is correctly sized.

6. Choose a reputable manufacturer like TOSUNlux, offering a range of MPCBs designed for various applications, including overload and short circuit protection for motors, power circuits up to 660V, and as full-voltage starters under AC3 load conditions. TOSUNlux also provides protection for circuit and power equipment in power distribution networks.

In summary, selecting the right MPCB entails considering the motor’s nameplate rated current and voltage, matching the MPCB’s current rating, ensuring sufficient wiring, and relying on a reliable manufacturer like TOSUNlux.

The market offers numerous brands of motor protection circuit breakers (MPCBs), providing a range of options. Here are some examples:

– A2S Advanced Safety Solutions
Andeli Group Company
– CBI-electric: low voltage
– Danfoss Industrial Automation
– Schneider Electric

MPCBs are available in a wide array of voltage ratings, including 230V, 380V, 415V, 440V, 500V, and 660V AC. They offer essential protection against short circuits and overloads for individual motor loads, catering to various motor sizes and installation types. MPCBs can be combined with NEMA and IEC contactors or solid-state motor controllers.

When selecting an MPCB, consider the motor’s nameplate rated current and voltage, opt for an MPCB with an appropriate current rating, ensure proper wiring, and prioritize a reliable manufacturer like TOSUNlux. Their commitment to quality and performance makes them a trusted choice.

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TOSUNlux MPCBs are highly adaptable and find suitability across a broad spectrum of applications. Industries such as manufacturing plants, conveyor systems, pumps, compressors, and HVAC systems can rely on these MPCBs for reliable motor protection.

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TOSUNlux has its own design team with a 5-people in-house design team, which provides 4-5 new series of products every year for our clients.

A Comprehensive Guide to Motor Protection Circuit Breakers (MPCBs)

Motor protection circuit breakers (MPCBs) are indispensable elements within electrical systems that safeguard electric motors from potential damage caused by overcurrent, short circuits, and other electrical faults. This article aims to provide a thorough understanding of MPCBs, their functions, and their wide-ranging applications.

What Exactly is an MPCB?

An MPCB represents a specialized type of circuit breaker that consolidates the short-circuit and isolation capabilities of a molded case circuit breaker (MCCB) with the motor’s overcurrent protection, as typically achieved by utilizing a traditional overload relay.

Offering Dependable Motor Protection:

MPCBs are explicitly engineered to deliver reliable protection for electric motors against overloads, short circuits, phase loss, and phase imbalance. These devices predominantly find utilization in two-component starter applications, where they operate in conjunction with a contactor to effectively manage motor loads.

Advantages Presented by MPCBs:

MPCBs offer a myriad of advantages when compared with traditional overload relays and fuses:
1. Higher Current Ratings: MPCBs possess the capability to handle higher current ratings, rendering them suitable for an extensive array of motor sizes and applications.
2. Adjustable Tripping Characteristics: The tripping characteristics of MPCBs can be adjusted to align with the specific requirements of motors, thereby bestowing a flexible approach to motor protection.
3. Compact Size: Despite their compact dimensions, MPCBs deliver high performance, effectively conserving space within electrical panels.
4. Wide Array of Accessories: MPCBs are accompanied by a diverse range of supplemental accessories, including auxiliary contacts, shunt trips, and undervoltage releases, all of which enhance their overall functionality.

Specifications of MPCBs:

MPCBs are available in various models and specifications, meticulously tailored to meet diverse application requirements. These specifications encompass distinct contact types, installation methods, and auxiliary contact configurations. Furthermore, MPCBs can handle different voltage ratings, with typical ratings extending up to 660V AC, and current ratings ranging from 0.1A to 80A.

Applications of MPCBs:

MPCBs hold substantial prominence in various industrial applications, which include but are not limited to:
1. Manufacturing Plants
2. Conveyor Systems
3. Pumps and Compressors
4. HVAC Systems
5. Motor-driven Machinery and Equipment

Choosing the Most Suitable MPCB:

When selecting an MPCB, it is advisable to consider the following factors:
1. The motor’s nameplate rated current and voltage
2. Ensuring that the MPCB’s current rating aligns with the motor’s specific requirements
3. Implementing adequate wiring systems capable of safely handling the rated current
4. Opting for a reliable manufacturer renowned for their high-quality MPCBs, such as TOSUNlux.

In conclusion, motor protection circuit breakers (MPCBs) play a pivotal role in electrical systems by offering a reliable means of safeguarding electric motors against overcurrents, short circuits, and other electrical faults. The advantages of MPCBs, including higher current ratings, adjustable tripping characteristics, and compact dimensions, make them highly desirable. Moreover, their extensive use across a wide range of industrial applications underscores their importance. Selecting an MPCB involves considering factors such as the motor’s rated current and voltage, as well as the specific requirements of the application at hand.

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