Exam 20: Troubleshooting Electric Motors

How can a technician tell if a belt is slipping?

Belt tension will not have any affect on the wear of the bearings.

The recommended way to discharge a capacitor is to ____.

If the resistance of the run winding is lowered, the imbalance in magnetic fields between the start and the run winding will be increased, and the starting torque of the motor will actually increase.

Pulleys must be in proper alignment or belt and bearing wear will occur.

An open winding in an electric motor means that ____.

A motor will not start when power is applied. If the belt is removed, the pulley spun, and power applied, and the motor continues to run, the first part to check is the _________________________.

If the cost of repairing the motor is close to the cost of replacing the motor, it would definitely pay to repair the motor if the new component carries a one-year warranty and the repaired motor carries only a 90-day guarantee.

Before testing a run or start capacitor with an ohmmeter, the capacitor should be discharged with a 20,000-ohm 5-watt resistor.

Open winding will not affect the resistance reading of the start winding as well as the resistance reading between the Run and Start terminals.

If the needle of an ohmmeter used to check a capacitor goes toward the 0 ohms reading, stops and falls back to 20,000 ohms, what does this mean?

Technician "A" says that while checking the windings of a compressor, a reading of 10 ohms or less from the common terminal to ground indicates that the motor is okay. Technician "B" says that the resistance of the start winding should always be less than the resistance of the run winding. Which of the following statements is correct?

A technician needs to check a single-phase compressor. He labels the three terminals "A," "B," and "C" and takes resistance readings of the windings. He reads 10 ohms from "A" to "B," infinity from "B" to "C," and infinity from "C" to "A." Identify the terminals.

Two common reasons for motor failure are improper pulley alignment and _________________________.

If a condenser fan motor grounds out, it will usually ____.

Technician "A" says that a shorted winding will result in an increased current flow through the winding. Technician "B" says that if a motor is to be replaced, a motor with a lower horsepower rating should always be used. Which of the following statements is correct?

If the resistance of the run winding decreases, the ____.

A motor has four leads out of it: two red and two black. The resistance between the red leads is 3 ohms. The resistance between the black leads is 5 ohms. The black leads are connected to the ____________________ winding.

What is a common mistake technicians make when trying to remove drive assemblies?

The leads of an ohmmeter using the R x 100 scale are placed on the terminals of a capacitor and then reversed. The needle does not move. This would indicate that the capacitor is ____________________.