Motor circuit breakers

This category of products includes motor circuit breakers, i.e. small-sized protective devices. Their main task is to prevent damage to the electric motor caused by short-circuits, overloads or starting blockage. Circuit breakers are also able to protect the entire mechanism in the event of the so-called power failure. phases. This is the basic element protecting lower power engines and ensuring their proper operation.

Motor Circuit Breakers – how do they work?

Even the most powerful electric motor is exposed to overloads or short circuits. This is due to the very design of this type of equipment and the fact that electricity is necessary for its operation. At any time, even the smallest failure of a given component can occur, which in turn will lead to the creation of an unwanted overvoltage. This, in turn, can result in the destruction of the entire engine. To avoid this, special motor switches, commonly known as thermal switches, are installed. As the name of these devices indicates, they are designed to cut off the electricity supply in the event of a short circuit or overload, and thus protect the entire mechanism against more serious failures. The same is true for phase loss.

Motor circuit breakers respond to overload and short-circuit currents. They can ensure uninterrupted operation of the motor, but only when there is a rated current in the circuit. Then the accessories are used to manually switch on or off the mechanism.

The operation of the circuit breaker is largely based on a thermal release. It is an element that reacts almost immediately when an overload is detected, i.e. to put it simply, the phenomenon that the voltage in the circuit turns out to be higher than the rated current. In this way, the release primarily protects the motor winding against overheating.

An important element of the circuit breakers is also the electromagnetic release, which is actually short-circuit motor protection. If there is a short circuit in the mechanism, this component is designed to react immediately and cut off the power. The electromagnetic release is directly responsible for protecting the motor during the already mentioned phenomenon of phase loss.

Motor Circuit Breakers – advantages

Most electric motors can be started without a switch. However, this is not a situation recommended for practice. Without this type of protection, the mechanism is exposed to serious damage, which can occur, even if you are dealing with new, unused equipment.

Motor circuit breakers are the foundation of the protection system for electric motors. They minimize the risk of complete destruction with often occurring defects leading to short circuits or overloads. The thermals work quickly, almost instantaneously. In the case of responding to a phase failure, the response time of the equipment is measured in milliseconds. The switches operate automatically, but also provide manual adjustment. What's important – this type of protection does not protect the motors themselves, but also the contactor. Due to high short-circuit resistance, there is no need to deprotect individual drive lines, but remember that circuit breakers should be installed before contactors. What's important – switches not only protect motor circuits, but also separate and connect them, depending on the need.

How to choose motor circuit breakers?

In order for the circuit breaker to fulfill its function, it should be correctly matched to the motor it is supposed to protect. The basic parameter to pay attention to is the motor current. Here we have two basic types of thermals to choose from: single-phase and three-phase. In addition, it is necessary to take into account the rated current supported. Information about this value should be provided on the engine board. The rule is to choose circuit breakers with slightly higher parameters. Normally, circuit breakers operate at a rated current of about 40A, but you can easily get more powerful ones that handle 80A. It is important that this type of equipment, regardless of these parameters, has an IP 65 protection class. Thanks to this, you can be sure that the circuit breaker will work without any problems even in the most difficult conditions.

What motors are the circuit breakers fitted to?

Switches are designed primarily (although it is not a strict rule) for low-power electric motors. However, there are no contraindications to mount them in slightly stronger mechanisms. In addition, they are most often installed in motors that are extremely exposed to overvoltages, short circuits and overloads (working in difficult environmental conditions).

What motor circuit breakers do we offer?

In the online store you can find various types of motor switches. We offer units adapted for mounting on the TH35 electrical installation rail. This is the most popular type of protection for electric motors. In addition, the resources of our store also include thermal bimetallic motor switches. This is a special type of protection that is triggered by deformation of the contained bimetal (hence the name), which cuts off the power supply. In addition, various accessories for circuit breakers are available for sale, including housings, triggers, knobs, bridges, relays, bases, contacts, mounting plates and many more.

We offer equipment only from reputable manufacturers. At you will find circuit breakers of such brands as ABB, Eti Polam, Hager, Legrand, Lovato, Eaton and Schneider Electric. We have units operating under a rated current of various values (range from 0.16A to 630A for the most advanced technological solutions). In addition, the offer includes two- and three-pole circuit breakers. It is possible to select the equipment in terms of the supported setting range of the minimum current (from 0.24A to 120A) and maximum (from 0.4A to 150A) or even rated voltage (values from 230V to 1000V).

Why is it worth buying motor circuit breakers at

We offer high-class accessories adapted to work with most electric motors. We make every effort to ensure that the order placed reaches the customer as soon as possible. Usually the lead time is up to three business days. The exception is when the product is not currently in stock. During this time, the delivery period may be extended. Information about the approximate time of order fulfillment is always on the product card, next to the technical specification.