Motor overload protection

Motor protections

Protections for electric motors

Motor protections, as the name implies, are electronic devices that maintain the correct operation of electric motors, electric motors and protect against overload, overheating and short circuit. Motor protections are an indispensable part and foundation in electrical engineering and automation and are indispensable in the construction of electrical systems. They can be combined with different types of contactors, monitoring relays, electromagnetic relays, sensors.

Electrical and mechanical damage

Overloading a motor can lead to electrical and mechanical accidents. Electrical accidents are caused by overvoltage, sudden drop in voltage, failure of one or two of the phases, short circuits where the current reaches levels that damage the motor. Mechanical failures are a locked rotor or rotor overload, resulting in overheating and an increase in current. Motor protections are of several types according to the phases, single-phase and three-phase, as well as according to the type of application in the way of operation, current protections, thermal protections and magnetic protections. They are intended for mounting on a DIN rail or electrical panel.

• current protections
• thermal-current protections
• thermal-magnetic protections

 

• single phase
• three-phase

Motor current protections

Current motor protections operate an automatic circuit breaker in case of excessive motor load. Motor protection of this type has a range of current values ​​at which it operates. The motor protection current values ​​can be adjusted depending on the need and the application. There are also models of motor current protection with automatic and manual reset.

Thermal current motor protections

Another type of motor protection is the motor thermal-current protection, and they have bi-metal thermal relays that monitor the temperature of the electric motor and prevent it from overheating. Higher quality motor protections of this type work precisely regardless of changes in ambient temperature. Models of this type can be direct current and alternating current.

Thermal-magnetic protections

Thermo-magnetic protections, as the name implies, work on the principle of induction, the coil inside the circuit breaker creates a very strong magnetic field when a fault current occurs, and the internal contacts immediately disconnect. They monitor for leaks, short circuits, as well as very large currents that can lead to motor overload and failure.