How does motor overload protection respond when current exceeds the predetermined value?

How does motor overload protection respond when current exceeds the predetermined value?

• A. It opens a normally closed contact.
• B. It closes a normally open contact.
• C. It short circuits the circuit.
• D. It reduces voltage to the motor.

Answer: (A)

Overload protection is meant to stop the motor when it tries to draw more current than it should. When the current exceeds the preset value, the protective element (often a thermal relay) trips and opens its contact. That contact is normally closed during normal operation, so opening it breaks the circuit and the motor loses power. This prevents overheating and damage. It doesn’t short the circuit, it doesn’t actively close a contact, and it doesn’t reduce voltage—it simply interrupts the current flow.

Overload protection is meant to stop the motor when it tries to draw more current than it should. When the current exceeds the preset value, the protective element (often a thermal relay) trips and opens its contact. That contact is normally closed during normal operation, so opening it breaks the circuit and the motor loses power. This prevents overheating and damage. It doesn’t short the circuit, it doesn’t actively close a contact, and it doesn’t reduce voltage—it simply interrupts the current flow.