🔍 Key Concepts

• Trace the control circuit from the red indicator (RB) back to the power source to see what must be closed for current to reach the lamp. • Note which auxiliary contacts (1CR and M) are in series with the red lamp, and under what operating condition each of those contacts is closed. • Compare the behavior of the overload contact (OL) and the interlock switches with the state of the red lamp – do they provide power to it or remove power from it?

💭 Think About

• When the motor is running normally, which contacts in the lower ladder diagram are energized and closed, especially those labeled 1CR and M? • If the motor trips on overload and the OL contact changes state, what happens to the 1CR coil and, in turn, to the contact feeding the red lamp? • Do the interlocks in the circuit supply power to the red lamp, or do they interrupt power and prevent either the coil or the motor from being energized?

✅ Before You Answer

• Verify exactly where the RB (red lamp) connects in the ladder: on which rung, and which contacts are in series with it. • Confirm whether the OL contact is in the same current path as the red lamp, and whether it would be open or closed during an overload trip. • Determine whether the M auxiliary contact is only closed when the motor contactor is pulled in and the motor is actually connected across the line.