Motors

Question 1

A line diagram shows the control devices in their___________ without regard to their_____________.

Answer 1

1. Logical sequence
2. Physical location

Question 2

Wiring & line diagrams displays all contacts in their _________ without any __________ applied.

Answer 2

1. De-energized state
2. External forces

Question 3

Three sectors of a control circuit.

Answer 3

1. Stop
2. Start
3. Run

Question 4

Manual motor starters must provide ______ protection unless exempted by code

Answer 4

O/L

Question 5

True or False: Manuel control circuits typically provide no or low voltage protection.

Answer 5

True

Question 6

Devices and control circuits some times fail. Electricians must ___________ sources of power to prevent injuries

Answer 6

Lock out

Question 7

True or false: 2 wire control typically provides high voltage protection.

Answer 7

False: no or low voltage

Question 8

When a magnetic motor starter protector is used with pilot devices, a greater degree of ________ may be achieved.

Answer 8

Control

Question 9

Push-buttons contacts may be ______ & _______.

Answer 9

N.O & N.C

Question 10

Pole contacts of a motor starter are intended to carry the ______ of the motor.

Answer 10

FLA

Question 11

The N.O auxiliary contact is called 5 contacts, Name them.

Answer 11

1. Holding
2. Maintaining
3. Run
4. Sealing
5. Memory

Question 12

Button interlocking that change state simultaneously. What is this act called?

Answer 12

Double acting

Question 13

Mechanical interlocking for F/R contactors, physically prevents both _________ from moving to the ________ simultaneously.

Answer 13

1. Contactor armatures
2. Closed position

Question 14

When a motor starter protector employs a disconnecting means as well as a short circuit protection, it is given the name ____________.

Answer 14

Combination starter

Question 15

A change in direction of a 3 phase motor may be accomplished by interchanging the connections of__________ leads.

Answer 15

Any 2

Question 16

A single phase condition will cause a motor to _____ and _______ when in operation.

Answer 16

1. Hum
2. Labour

Question 17

Additional start buttons must be connected in what?

Answer 17

Parallel

Question 18

A relay is a small _____________ device

Answer 18

Electromagnetic

Question 19

What type of pressure switch is generally used to sense small changes in low pressure systems?

Answer 19

Diaphragm switch

Question 20

What type of float switches have a differential setting?

Answer 20

Rod- operated
Chain operated

Question 21

What are 2 basic classifications of timers?

Answer 21

1. On delay
2. Off delay

Question 22

What are 3 advantages of a piezoresistive sensor?

Answer 22

1. Small
2. Reliability
3. Accurate

Question 23

What are flow switches used for?

Answer 23

To detect movement of air/ liquid and is constructed from a snap action micro switch

Question 24

Flow switches generally contain a _________ & _________ micro switch. They are also used to control ______________.

Answer 24

1. Single pole
2. Double throw
3. Low current loads

Question 25

In a flow sensor, what detects the amount of liquid and air in pipes/ ducts?

Answer 25

Transducer

Question 26

Electromagnetic flow sensors operate on what?

Answer 26

1. Principle of Faradays Law Faraday law: when a conductor moves through a magnetic field a voltage is induced into the conductor

Question 27

Orifice plate flow sensors operate by inserting a ________ with an orifice of known size into the flow path

Answer 27

Plate

Question 28

When a moving liquid strikes an object, a swirling current, called a vortex is created. This is known as?

Answer 28

Vortex flow sensors

Question 29

A _________ Operates on the principle that air or gas flowing across a surface causes heat transfer. They’re are also commonly known to sense smaller amounts of air/gas.

Answer 29

Airflow switch

Question 30

A __________ can measure flow rate by thermal energy dissipation. Typically have 2 positive coefficients & sense flow of air, water, & oil.

Answer 30

Calorimetric flow sensor

Question 31

A __________ is used to detect when an object is present or absent. Activated by motion of machine/ object. Contain a type of bumper arm.

Answer 31

Limit switches

Question 32

Limit switches are used as _________ to control ______, ________ .

Answer 32

1. Pilot devices 2. Relays 3. Motor starters

Question 33

What are the 2 micro switches?

Answer 33

1. Subminiature micro switch 2. Micro limit switch

Question 34

Restricts air flow through an orifice to rubber bellows or diaphragm. This is know as?

Answer 34

Pneumatic timer

Question 35

Low and no voltage protection aides in protecting an operator from motor driven machinery starting __________ upon restoration of full systems voltage

Answer 35

Unexpectedly

Question 36

Low and no voltage protection cannot _______ the safety of an operator

Answer 36

Ensure

Question 37

Magnetic starters tend to have what type of wiring control?

Answer 37

3 wire control