Question 316Electricity & Electronics - QMED

70% to pass

What is the primary functional purpose of the KM1 contactor as shown in the illustration? Illustration EL-0080

Diagram for USCG Electrical QMED: What is the primary functional purpose of the KM1 contactor as shown in the...
Aconnects the motor across line while in the start mode
Bconnects the autotransformer in "wye" configuration while in the start mode
Cconnects the motor to the autotransformer while in the start mode
Dconnects the motor across line wile in the run mode
AI Explanation

The correct answer is B) connects the autotransformer in "wye" configuration while in the start mode. The KM1 contactor is used to connect the autotransformer in a "wye" configuration during the motor's starting sequence. This allows the motor to draw a reduced current from the power supply, limiting the initial inrush of current and easing the strain on the electrical system. Once the motor reaches the desired speed, the KM1 contactor opens, and the motor is connected directly to the line voltage (across the line) in the run mode. The other options are incorrect because they do not accurately describe the primary function of the KM1 contactor in this application. Option A, C, and D do not correctly identify the contactor's role in connecting the autotransformer during the starting sequence.

Want to practice with timed exams?

Download Coast Guard Exams for the full exam experience.

Get the App