1. After new motors and controls are installed, they should be checked for operation under load for an initial period of
at least one hour.
a. True
b. False
2. Ball-bearing motors can be mounted on sidewalls or the ceiling.
a. True
b. False
3. To reverse rotation of a single-phase motor, interchange any two line leads.
a. True
b. False
4. LISTENING may indicate burning insulation or a coil failure.
a. True
b. False
5. A jumper should never be placed across a power-consuming device, such as a contactor coil.
a. True
b. False
Name: Class: Date:
Unit 59 Motor Startup and Troubleshooting Basics
6. A loose electrical terminal connection or a control pilot device with an intermittent open circuit can cause ____.
a. wear on magnet b. a motor to stop running
c. pitted, worn, or broken arc-chutes d. insulation failure
7. For low trip, possible causes may be ____.
a. fluid out or too light; vent too large; high temperature; wrong heaters
b. wrong coil; assembled wrong
c. not enough capacitance; not enough resistance
d. dirt; worn parts; improper adjustment; corrosion; mechanical binding
8. For resistor failure, possible causes may be ____.
a. wrong heater; relay in high ambient
b. abrasive dust; very heavy duty; no lubrication
c. overcurrent; moisture; corrosive atmospheres
d. abrasive dust; dirty oil; water in tank
9. For corrosion, possible causes may be ____.
a. liquid frozen in capillary tube
b. mechanical abuse; severe vibration; shock
c. overheating; overvoltage; voltage surges
d. excess moisture; salt air; acid fumes
Name: Class: Date:
Unit 59 Motor Startup and Troubleshooting Basics
10. The power diodes in the converter can be tested with an ____.
a. ohmmeter b. ammeter
c. autometer d. R-meter
Name: Class: Date:
Unit 59 Motor Startup and Troubleshooting Basics