In a basic forward-reverse motor control circuit, which arrangement provides interlocking to prevent simultaneous energization of forward and reverse?

• A. A single contactor to handle both directions
• B. A bypass contact to avoid interlocks
• C. Two contactors with interlocking
• D. A single motor starter with a forward/reverse switch

Answer: (C)

In a basic forward-reverse motor control circuit, preventing both directions from being energized at the same time is essential to avoid a short across the supply and damage to the motor. This is achieved by using two separate contactors—one for forward and one for reverse—and interlocking them so that energizing one coil blocks the other from closing. The interlock can be mechanical or electrical, but the result is the same: only one direction can be energized at a time, ensuring safe operation and preventing a direct path from one supply to the other.

The other setups fail to provide that guaranteed separation. A single contactor that handles both directions doesn’t give a true two-path interlock, so there’s no built-in safeguard preventing both circuits from closing. Bypass interlocks defeat the purpose by removing the interlock entirely, allowing unsafe simultaneous energization. A single motor starter with a forward/reverse switch might allow direction selection, but without proper interlocking, it cannot reliably prevent both paths from energizing together, risking a short or motor damage.