🔍 Key Concepts

• Low-voltage protection vs low-voltage release – what happens to the motor control circuit when supply voltage is lost and then comes back? • How an overload relay is wired when it is intended to trip (open) the motor contactor versus only operate an indicator light. • Reading the diagram: follow the path through the line contactor (LC) coil and the overload relay contacts back to the motor leads T1–T3 and overload elements OL.

💭 Think About

• Look at the control circuit on the left: if power to the control circuit is lost while the Start-Stop switch is in the RUN position, what happens when power returns? Does the motor restart automatically, or must it be restarted manually? Relate that behavior to low-voltage protection vs release. • Trace the overload relay contacts in series with the line contactor coil. If the overload operates, does it only energize a lamp, or does it interrupt power to the line contactor (and therefore the motor)? • Notice the dashed wiring to the ‘Run’ and ‘Overload’ lights. Which device actually removes power from the motor, and which device merely provides indication? How does that match the answer choices?

✅ Before You Answer

• Verify whether loss of control power de-energizes the line contactor (LC) coil and whether the circuit has to be re-started after voltage is restored (key for low-voltage protection vs release). • Confirm that the overload relay contacts are in series with the LC coil so that when they open, the contactor drops out and the motor is de-energized (overload trip behavior). • Check that the ‘Overload’ light is fed through auxiliary contacts and does not by itself control motor power, so you don’t confuse indication with protection.