induction
solid state
thermal
electromagnetic E. all above
Answer is Right!
Answer is Wrong!
The correct answer is E. Overload relays are of type induction, solid state, thermal, and electromagnetic.
- Induction overload relays use the principle of electromagnetic induction to detect overloads. When the current in the coil of the relay exceeds a certain value, it creates a magnetic field that attracts a metal armature. This armature then opens the contacts of the relay, which interrupts the flow of current to the load.
- Solid state overload relays use semiconductor devices to detect overloads. When the current in the load exceeds a certain value, the semiconductor devices turn off, which interrupts the flow of current to the load.
- Thermal overload relays use a bimetallic strip to detect overloads. When the current in the load exceeds a certain value, the bimetallic strip heats up and bends, which opens the contacts of the relay, which interrupts the flow of current to the load.
- Electromagnetic overload relays use a solenoid to detect overloads. When the current in the load exceeds a certain value, the solenoid pulls in a plunger, which opens the contacts of the relay, which interrupts the flow of current to the load.
Overload relays are used to protect electrical motors and other equipment from damage caused by overloads.