test 6

Question 1

excess energy redirected back to AC supply

Answer 1

Regenerative brake

Question 2

The Frequent starting and stopping of a motor for short periods of time

Answer 2

jogging

Question 3

the arrangement of contacts is such a way that both sets of contacts cannot be physically closed at the same time

Answer 3

mechanically interlock

Question 4

motor breaking in which motor connection is reversed so that the motor develops a counter torque the acts as a brake

Answer 4

plugging

Question 5

a relay that has an infinite number of possible output voltages within the rated range of the relay

Answer 5

analog - switching relay

Question 6

Used to reduce the time it takes a rotating motor to stop spinning

Answer 6

braking

Question 7

The frequency of the voltage used to control motor speed

Answer 7

fundamental frequency

Question 8

the trip point from the time the motor starts until the first time the overloads trip

Answer 8

cold trip

Question 9

a stopping method in which the level of voltage applied to motor is reduced as the motor decelerates

Answer 9

Ramp stop

Question 10

The part of the relay to which the control component is connected

Answer 10

input circuit

Question 11

a converter is a device that converts ______ to ________

Answer 11

AC voltage to DC voltage

Question 12

although any 2 lines may be interchanged to reverse a 3 phase motor, the industry standard is to interchange ___ and ____.

Answer 12

L1 and L3

Question 13

reversal of a DC compound motor is accomplished by reversing the _________ connection only

Answer 13

armature windings

Question 14

What is ramping

Answer 14

acceleration or deceleration of a motor over some period of time

Question 15

A limitation of EMRs is they

Answer 15

generate EMI on power lines

Question 16

Current to an AC motor drive is limited by

Answer 16

the size of the conductors to the drive
OCPD size
transformers delivering power to the system

Question 17

The advantage of using friction brakes is

Answer 17

Simplified maintenance and lower initial cost

Question 18

AN inverter is a device that converts _____ to _____

Answer 18

DC voltage to AC voltage

Question 19

AC motors should not be driven at speeds greater than ___ above their rated nameplate speed.

Answer 19

10%

Question 20

A ________ is an SSR that turns on a load when the voltage at the load crosses near or at the zero point

Answer 20

Zero - switching relay

Question 21

to prevent damage to diodes in a converter and to AC motor drive electronic circuits protection against ______ must be included in the drive.

Answer 21

Transient voltages

Question 22

What are the 2 physical qualities which must be connected in a motor drive?

Answer 22

speed and torque

Question 23

a variable frequency drive provides 48 hz AC voltage to a 3 phase 480 volt AC motor which has 6 poles per phase. What would be the synchronous speed of the motor with the voltage applied.

Answer 23

(120*f)/#of poles

(120*48)/6

960

Question 24

5 limitations for a SSR

Answer 24

1. requirement for a heat sink due to voltage drop across the switch
2. residual resistance
3. 1 set of contacts
4. current leakage
5. complete device needs to be replaced

Question 25

what are the 3 main sections of an AC motor drive

Answer 25

Converter
DC bus
inverter

Question 26

name the parts of a solid state relay

Answer 26

input circuit
optocoupler
LED
output circuit
photo detector
light