Features Of Maual Motors

Question 1

List two types of manual motor starters

Answer 1

Toggle switch, push switch

Question 2

What does a toggle switch do

Answer 2

It is a snap on switch having a simple on and off switch.
It can be a single pole or double pole.

Question 3

What is a push botton switch

Answer 3

Similar to a toggle switch except they use two different buttons to activate the contacts.

Question 4

What is a drum switch

Answer 4

It is a rotary- action switch.
It’s normally used to control speed and change the direction of motors.
The moving contacts on the shaft are connected in series.

Question 5

What is Melting alloy overload protection relays

Answer 5

Often called (solder pot relay) which is also a part in it containing a ratchet wheel and a set of normally closed electrical contacts.
It has a heater element and a contact witch are connected in series

Question 6

What is a Bimetallic strip overload relay

Answer 6

The bimetallic stip is mechanically linked to a set of n.c electrical contacts. If sufficient heat is produced in the heater element the strip bends. Opening the line of contact to the motor

Question 7

What does the melting alloy over load do when the current is high for a long period of time
And what is the other name for it

Answer 7

If the current is high for a long period of time the elements will heat up causing the alloy in the solder spot to liquefy.

Once the relay cools the solder will harden and the ratchet wheel can be reset to close the line contacts again

Low voltage contact = LVC

Question 8

What is low voltage protection

Answer 8

If a machine has low voltage protection it means it will not restart if power is returned to it

Question 9

What is lVP

Answer 9

Low voltage protection
If the motor has a

Question 10

Three functions other than stopping and starting a motor controller l can provide

Answer 10

Running protection of the motor
Varies the speed of the motor
Automatic and remote control of the magnet

Question 11

What is the fundamental difference between a magnetic connecter and a magnetic motor starter?

Answer 11

The magnetic motor starter consist of a magnet connecter plus overload, relay protection

Question 12

What is the difference between the power circuit and the control circuit of motor

Answer 12

The power circuit = the main line contacts
The control circuit = electromagnetic, coil, and auxiliary contact

Question 13

A three phase motor requires an overload ________ in series with each of the line conductors to the motor

Answer 13

Heater

Question 14

Selection of the heater is based on the full load__________ of the motor, which is easily determined for the____________ of the motor

Answer 14

Current, nameplate

Question 15

List four components found in a power circuit of an crossline, magnetic starter circuit

Answer 15

Disconnect switch
Fuse
Power contacts
Heater elements

Question 16

List three components found in the control circuit of a magnetic starter

Answer 16

Two positions selector switches
Motor coil
Auxiliary contact

Question 17

A two wire control circuit provides under voltage____________

Answer 17

Release

Question 18

At three wire control circuit provides under voltage____________

Answer 18

Protection

Question 19

Two wire control circuits usually include___________ Contacts initiating devices

Answer 19

Maintained

Question 20

What is the purpose of a pilot light?

Answer 20

It’s used to turn on a motor in a remote location

Question 21

When operating a motor from two or more locations the stop buttons are connected in___________ and the buttons are connected in___________

Answer 21

Serious
Parallel

Question 22

What is meant by full voltage control

Answer 22

It is when the pilot device is in the control circuit operating at the same voltage as the motor or power supply

Question 23

How does a wiring diagram defer from a schematic diagram?

Answer 23

Schematic diagram, uses symbols and interconnecting lines

wiring diagram shows where the wires are connected and where they are located

Question 24

What is a wire numbering system?

Answer 24

It is a numeric marking method, applied to schematic diagrams to help identify conductor terminations

Question 25

Why are numbering systems helpful?

Answer 25

They are interconnected with the conductors
Eg the numbers go to the numbers 2-2 3-3 and so on

Question 26

Why is it sometimes necessary to use? Control relays in conjunction with magnetic motor starters

Answer 26

If a magnetic starter does not have enough auxiliary control for the control circuit operation then one or more control relays are used

Question 27

When I normally open contact on a control relay is rated at 10 A AC. Does that mean it could break and break all values of current up to and including 10

Answer 27

It means that it has a continuous value of 10A

Question 28

What is a latching relay?

Answer 28

A latching relay is a relay that when energized the coil and relay remain mechanically latched in the closed position

Question 29

What is meant by the term jogging

Answer 29

Jogging is a quickly repeated closure of a circuit. It starts a motor from rest and causes small movements of the motor driven machine.

Question 30

What hazard can occur when using only a simple jog button with a stop and start circuit

Answer 30

The motor may continue to run if the jog button closes before the seal in contact has a chance to open

Question 31

What do you do if your jog button with a stop start switch creates a hazard

Answer 31

Are using a definite break device, such as a selector switch, or a control relay in the jog control, seal in circuit