Question 1

Large motors should be connected directly across the line on startup.

Accepted Answer

Large motors should not be connected directly across the line on startup as it can cause excessive current draw and damage to the motor. It is recommended to use a motor soft starter, variable frequency drive or other motor starting techniques to reduce the inrush current and protect the motor.

Question 2

Common applications of automatic starters provide control of small machine tools, fans, pumps, oil burners, blowers, and unit heaters.

Accepted Answer

False

Question 3

A motor may draw up to a percent current surge on starting.&#10;A)100&#10;B)300&#10;C)600&#10;D)900

Accepted Answer

A motor may draw up to 600 percent current surge on starting. This is due to the high starting torque required to get the motor moving from a standstill. The current surge can cause problems with the electrical system if not properly accounted for, and is often addressed through the use of soft starters or variable frequency drives. Choices A, B, and D are incorrect as they do not accurately reflect the typical current surge seen on motor starting.

Question 4

When an overload relay trips, the starter mechanism unlatches, opening the contacts to stop the motor.

Accepted Answer

When an overload relay detects an excessive current, it will trip and cause the starter mechanism to unlatch and open the contacts, which stops the motor. When an overload relay trips, it interrupts the power supply to the motor and causes the starter mechanism to unlatch, opening the contacts and stopping the motor.

Question 5

Only one overload relay is required in either the single-pole or double-pole motor starter.

Accepted Answer

Only one overload relay is required in either the single-pole or double-pole motor starter.

Question 6

Manual push-button starters are designed for infrequent starting of .&#10;A)small AC motors&#10;B)large DC motors&#10;C)small DC motors&#10;D)large AC motors

Accepted Answer

Manual push-button starters are typically used for small AC motors due to their simplicity and cost-effectiveness for infrequent starting applications.

Question 7

In the event of a power failure, a manual starter motor automatically restarts when the power returns.

Accepted Answer

A manual starter motor does not automatically restart when the power returns.

Question 8

Manual push-button starters may be used to control single-phase motors rated up to .&#10;A)5 hp&#10;B)10 hp&#10;C)15 hp&#10;D)20 hp

Accepted Answer

Manual push-button starters are suitable for controlling single-phase motors rated up to 5 hp. Beyond 5 hp, other types of starters such as magnetic or electronic starters are required. Manual push-button starters are not recommended for controlling motors with higher power ratings as they may not be able to handle the high starting current that larger motors require. Therefore, the best choice for a single-phase motor would be up to 5 hp.

Question 9

Thermal overload units are widely used on both the fractional and integral horsepower manual starters for protection of motors from sustained electrical overcurrents that could result from overloading of the driven machine or from ____.

A)excessively low line voltage
B)excessively low power load
C)excessively high line voltage
D)excessively high power load

Accepted Answer

Excessively low line voltage can cause motors to draw more current to maintain torque, leading to overheating and potential damage, which thermal overload units help protect against.

Question 10

A manual starter is a(n) with motor overload protection.&#10;A)pressure switch&#10;B)limit switch&#10;C)on-off switch&#10;D)float switch

Accepted Answer

A manual starter is essentially an on-off switch that includes motor overload protection to prevent the motor from drawing too much current and overheating.

Deck 2: Fractional and Integral Horsepower Manual Motor Starters