USCG Exam PracticeMotor controllers and remote control
When a control, interlock, or indicator circuit operating above 24 volts cannot be energized from the load side of the motor disconnect device, and an independent disconnect device is used per 46 CFR §111.70-7(d)(1), which additional requirement must be met?
- A. The independent disconnect must be interlocked to open automatically when the motor disconnect opens
- ✓ The two independent disconnect devices must be adjacent to each other, and a fixed warning sign must be on the exterior of the main disconnect device doorCorrect
- C. The control circuit voltage must be reduced to 24 volts or less before the independent disconnect is installed
- D. The independent disconnect must be located at the remote control station rather than at the controller
Why B is correct
46 CFR §111.70-7(d)(1) requires that when an independent disconnect device is used for the control circuit, the two independent devices must be adjacent to each other, and a fixed sign warning the operator to open both devices to completely disconnect the motor and controller must be affixed to the exterior of the main disconnect device door. No automatic interlock or voltage reduction is specified.
Cited:46 CFR §111.70-7