Magnetothermic Motor Circuit Breakers

Magnetothermic motor circuit breakers have the advantage of being able to protect all types of motor, whether asynchronous, three-phase or single-phase. Schneider motor circuit breakers sold by One-Elec are perfectly suited to domestic, commercial and industrial use. Unlike magnetic circuit breakers, magnetothermic motor circuit breakers offer double protection:

- Thermal protection: all motor phases are protected by a bimetallic strip (thermal trip device) which, in the event of prolonged overcurrent, heats up by Joule effect and triggers a mechanism that opens the contacts. The tripping threshold is adjustable directly on the motor circuit-breaker.

- Magnetic protection: the magnetic trip unit (protection against short-circuits) is based on the creation of an instantaneous magnetic field (0.1sec) which actuates a moving part and opens the contacts. The magnetic part of the motor circuit-breaker can be adjustable on high-current circuit-breakers (moulded case type: NSX range) or fixed, depending on the circuit-breaker range.

Applications and benefits

One of the advantages of the motor circuit breaker is that it is suitable for various types of motors and applications, including hazardous machinery. In addition, they can be used as control switches to manually start and stop motors. Magnetothermic motor circuit breakers can be very useful in industrial environments where motors are subjected to demanding operating conditions. They make a major contribution to avoiding unscheduled stoppages, maintaining constant production and minimising the risk of accidents due to electrical malfunctions.

Choice and installation

When choosing a motor circuit breaker, it is crucial to calibrate the current according to the motor specifications, generally indicated on the nameplate. The range of Schneider Electric circuit-breakers you will find in our online shop offers a wide choice for various currents and applications, with D-type tripping curves particularly suited to motors with high inrush currents. These circuit-breakers are designed to withstand the most rigorous conditions and offer reliable protection against electrical faults.

Correct installation of these devices is also essential to guarantee their effectiveness. Circuit-breakers must be installed in appropriate enclosures and correctly connected to the motors and other equipment they protect. Regular inspections and proper maintenance are also necessary to ensure that circuit breakers operate correctly and continue to protect motors and other electrical equipment effectively.

In conclusion, magnetothermic motor circuit breakers are essential components for the protection of electric motors. The range of Schneider Electric circuit breakers available from One-Elec provides reliable protection that can be adapted to a multitude of applications, whether domestic, tertiary or industrial. By opting for quality motor circuit breakers, you are investing in the durability and performance of your equipment, while minimising the risk of electrical incidents and optimising energy consumption.