USCG Exam PracticeMotor controllers and remote control
Per 46 CFR §111.70-7(b), the controller must be designed so that an accidental ground in a remote control circuit cannot cause which two specific failures?
- A. The overload relay to reset, or the motor to overheat
- ✓ The stop switches to fail to operate, or the motor to startCorrect
- C. The branch circuit breaker to trip, or the motor to reverse direction
- D. The seal-in contact to open, or the contactor to drop out
Why B is correct
46 CFR §111.70-7(b) states the controller must be designed to prevent an accidental ground in a remote control circuit from causing the stop switches to fail to operate or causing the motor to start. These two failure modes represent the primary safety hazards of an undetected ground fault in a control circuit.
Cited:46 CFR §111.70-7