Question 1

To reverse rotation of a single-phase motor, interchange any two line leads.

Accepted Answer

To reverse the rotation of a single-phase motor, you typically interchange the connections on the start winding or the connections leading to the start or run capacitor, not the line leads. Interchanging line leads does not affect the rotation direction in single-phase motors.

Question 2

For corrosion, possible causes may be .&#10;A)liquid frozen in capillary tube&#10;B)mechanical abuse; severe vibration; shock&#10;C)overheating; overvoltage; voltage surges&#10;D)excess moisture; salt air; acid fumes

Accepted Answer

Excess moisture, salt air, and acid fumes are all known to cause corrosion in various materials. Liquid frozen in capillary tube, mechanical abuse, severe vibration, and shock may cause damage to the material, but do not typically lead to corrosion. Overheating, overvoltage, and voltage surges can cause electrical damage, but do not directly cause corrosion. Excess moisture, salt air, and acid fumes are all known causes of corrosion. Liquid frozen in a capillary tube and mechanical abuse/vibration/shock may cause other issues, but they are not typically associated with corrosion. Overheating, overvoltage, and voltage surges may cause damage to electronic components, but they do not cause corrosion.

Question 3

LISTENING may indicate burning insulation or a coil failure.

Accepted Answer

Listening is not a method to detect burning insulation or coil failure; these issues are typically identified through smell, visual inspection, or electrical testing.

Question 4

A loose electrical terminal connection or a control pilot device with an intermittent open circuit can cause .&#10;A)wear on magnet&#10;B)a motor to stop running&#10;C)pitted, worn, or broken arc-chutes&#10;D)insulation failure

Accepted Answer

A loose electrical terminal connection or a control pilot device with an intermittent open circuit can cause a motor to stop running. It can interrupt the electrical current supply to the motor, causing it to stop running. A loose electrical terminal connection or a control pilot device with an intermittent open circuit can cause a motor to stop running.

Question 5

The power diodes in the converter can be tested with an .&#10;A)ohmmeter&#10;B)ammeter&#10;C)autometer&#10;D)R-meter

Accepted Answer

The power diodes in the converter can be tested using an ohmmeter. An ohmmeter measures the resistance of a component, and in the case of a diode, it can be used to test the forward and reverse resistance. This can help determine if the diode is functioning properly or if it is damaged and needs to be replaced. An ammeter measures current, which is not useful for testing power diodes. An autometer and R-meter are not common tools and are not typically used for this type of testing. Power diodes can be tested for continuity and resistance using an ohmmeter. It can help detect if the diode has an open or short circuit. An ammeter measures current, not resistance, so it would not be the best choice. There is no such thing as an autometer, and an R-meter may not be commonly used for testing power diodes.

Question 6

After new motors and controls are installed, they should be checked for operation under load for an initial period of at least one hour.

Accepted Answer

It is important to check the motors and controls under load for an extended period of time to ensure they are functioning properly and can handle the required workload. It is recommended to check new motors and controls for operation under load for an initial period of at least one hour to ensure that they are functioning properly.

Question 7

A jumper should never be placed across a power-consuming device, such as a contactor coil.

Accepted Answer

Placing a jumper across a power-consuming device like a contactor coil can cause damage to the device and create a safety hazard. It is important to follow proper electrical wiring practices and not bypass any safety mechanisms. Placing a jumper across a power-consuming device will short-circuit the device and damage it.

Question 8

Ball-bearing motors can be mounted on sidewalls or the ceiling.

Accepted Answer

Yes, ball-bearing motors can be mounted on sidewalls or the ceiling. Ball-bearing motors can be mounted on either the sidewalls or the ceiling.

Question 9

For resistor failure, possible causes may be .&#10;A)wrong heater; relay in high ambient&#10;B)abrasive dust; very heavy duty; no lubrication&#10;C)overcurrent; moisture; corrosive atmospheres&#10;D)abrasive dust; dirty oil; water in tank

Accepted Answer

Overcurrent can cause the resistor to burn out, moisture can corrode the resistor, and corrosive atmospheres can also damage the resistor. The other options may cause problems in other parts of the system, but they are not directly related to resistor failure. Overcurrent, moisture, and corrosive atmospheres are all potential causes of resistor failure. Wrong heater and relay in high ambient (choice A) may cause other issues but are not directly related to resistor failure. Abrasive dust and heavy duty without lubrication (choice B) may cause wear and tear on equipment but are not specific to resistor failure. Abrasive dust, dirty oil, and water in tank (choice D) may cause contamination and malfunction, but again, this is not specific to resistor failure.

Question 10

For low trip, possible causes may be .&#10;A)fluid out or too light; vent too large; high temperature; wrong heaters&#10;B)wrong coil; assembled wrong&#10;C)not enough capacitance; not enough resistance&#10;D)dirt; worn parts; improper adjustment; corrosion; mechanical binding

Accepted Answer

The answer of For low trip, possible causes may be...

Deck 59: Motor Startup and Troubleshooting Basics