Deck 24: Resistor and Reactor Starting for Ac Motors

Question 1

Reactors limit in-rush current with ____________________ instead of resistance.

Answer 1

inductive reactance

Question 2

Resistors connected in series with the motor limit the amount of in-rush current.

Answer 2

True

Question 3

One way of determining when to shunt the resistors out of the circuit is by sensing motor current.

Answer 3

True

Question 4

Figure 24-4
In the circuit shown in the accompanying figure, the current sensor contacts are normally open.

Question 5

Some control circuits sense ____________________ speed to determine when to shunt the resistors out of the power line.

Question 6

In a resistive circuit, the current will take some time to reach its full Ohm's law value.

Question 7

In an inductive circuit, the current must rise at an exponential rate.

Question 8

Why is time delay one of the most popular methods of determining when to connect the motor directly to the power line?

Question 9

Some resistor and reactor starters use multiple steps of starting. How is this accomplished?

Question 10

Current ____________________ are used to sense the amount of motor current.

Question 11

____________________ is accomplished by connecting resistors in series with the motor during the starting period.

Question 12

What are two of the most common methods of reducing the amount of starting current?

Question 13

Figure 24-1
The accompanying diagram uses ____________________ to shunt the resistors out of the circuit after some period of time.

Question 14

Name two conditions where it is not possible to start a motor across-the-line.

Question 15

Figure 24-1
In the accompanying figure, what happens right after the START button is pressed?