Rotating Machinery

Front 1

Rotating Machinery

Back 1

Has spinning or rotating shaft & electricity as input/output.

Front 2

What are the 2 types of motors?

Back 2

Incremental & Continuous

Front 3

What is an incremental motor?

Back 3

Uses an electrical input to rotate shaft by specific degrees.

Front 4

Digital Incremental Motor

Back 4

A "Stepper" motor. uses digital pulses to position the shaft.

Front 5

Analog motor

Back 5

Uses specific voltages to position the shaft.

Front 6

Continuous Motor

Back 6

smooth running, meant to run .. continuously.

Front 7

Generator

Back 7

A motor that has a mechanical input and outputs electricity.

Front 8

What is RPS/RPM?

Back 8

Rotations Per Minute/Rotations Per Second.

Front 9

What determines the Speed of a motor?

Back 9

Voltage applied

Front 10

What is Torque?

Back 10

A Twisting Force.

Front 11

What is Torque Measured in?

Back 11

ft • lb, determined by Voltage and Current.

Front 12

What is Torque indirectly proportionate to?

Back 12

RPM

Front 13

What is CEMF?

Back 13

Counter Electromotive Force.

Front 14

What is a Load?

Back 14

For Motors: Anything that requires a rotating motion.

For Generators: Electric circuits to power.

Front 15

Define Power.

Back 15

The amount of work accomplished (The ability to accomplish work?)

Front 16

P = ?

Back 16

P = Torque x RPM x K.

Given in ft • lbs/sec.

if Load +, RPM -, CEMF -, Torque +, Power +.

Front 17

Define Motor Efficiency

Back 17

How well motor converts applied voltage to work. Pin and Pout converted to watts, calculated as a percent.

Efficiency = Pout / Pin x 100

Front 18

What Lenz's Law?

Back 18

The polarity of an induced electromagnetic force is such that it sets up a current, the magnetic field of which always opposes the change of the existing magnetic field.

"An induced current is always in such a direction as to oppose the motion or change causing it"

Front 19

When is torque greatest?

Back 19

When there is no conductor rotation. no rotation = no CEMF.

Front 20

How do you calculate a Watt?

Back 20

Watts = AMPs x VOLTs

Front 21

1 HP = ?

Back 21

550 ft • lb/sec. or

33,000 ft • lb/min.

746 Watts

Front 22

Electrical power is displayed in..

Back 22

Watts

Front 23

Mechanical Power is desplayed in..

Back 23

Horse Power

Front 24

What is the purpose of the commutator and brushes?

Back 24

To constantly switch the polarity of the rotor.

Front 25

True DC Motors use (permanent OR Electro - magnets)

Back 25

Electromagnets.

Front 26

How are the windings placed in a DC Shunt Motor?

Back 26

Stator and Rotor windings are placed in parallel with each other.

Front 27

How are the windings placed in a Series DC Motor?

Back 27

Stator and Rotor windings are in series.

Front 28

How is electricity created in a generator?

Back 28

Pass a conductor through a magnetic field, and a current is produced.

Front 29

What kind of signal does a 1 loop, or 2 pole, generator produce?

Back 29

Pulsating DC.

Front 30

If armature is parallel to stator field..

Back 30

No voltage is produced.

Front 31

Commercial generators normally have how many loops or poles?

Back 31

12 to 24 loops, 24 to 48 poles.

Front 32

What type of DC generator uses an external power source to power the stator?

Back 32

Separately excited DC Generator.

Front 33

What type of DC generator uses the same power source for both rotor and stator?

Back 33

Self-excited DC Generator.

Front 34

Define Retentivity:

Back 34

Small amount of magnetism that remains after the magnetizing force has been removed.

Front 35

Coils around the stator are called:

Back 35

Field Coils.

Front 36

Compound DC Motors contain field coils where?

Back 36

In Series AND Parallel with the Rotor.

Front 37

What is a Long Shunt?

Back 37

Series AND rotor in parallel w/ shunt.

Front 38

What is a Short Shunt?

Back 38

Shunt in parallel w/ rotor only.

Front 39

Shunt DC Motors -

Back 39

Used for high speed and constant torque applications.

Front 40

Series DC Motors -

Back 40

Less torque at higher speeds than shunt. More torque when locked.

Front 41

Torque and Acceleration are...

Back 41

Directly Proportional.

Front 42

4 components of a BLDC:

Back 42

Rotor

Stator

Commutation Electronics

Rotor Position Sensors

Front 43

What determine Phase of a Motor?

Back 43

# of windings in stator.

Front 44

Where is the Permanent magnet in a BLDC?

Back 44

on the Rotor.

Front 45

Define BLDC:

Back 45

Brushless DC motor.

Front 46

Torque and Inertia are...

Back 46

Inversely Proportional.

Front 47

What are the 4 functional groups of the BLDC Controller?

Back 47

Sensors

Motor Drive Circuit

Interface Circuit

Microprocessor or other control device

Front 48

BLDC Sensors can be ? or ? type.

Back 48

Photocell or Hall effect Sensor.

Front 49

Full wave motor controller allows what?

Back 49

Allows motor action in both directions by controlling stator polarities.

Front 50

How do you Calculate Torque?

Back 50

Ia x If x K.

Ia = Armature Current

If = Stator (field) Current

K = Constant (usually 1)

Front 51

if Ia = .5A, If = .6A ..What is torque?

Back 51

.3 ft • lbs.

Front 52

It is impractical to try and measure armature current.. the only 2 measurements needed to calculate torque are:

Back 52

Vapplied & If (Stator Current).

If = V/R.

Front 53

To determine Ia at a set RPM:

Back 53

Ia = It - If

Front 54

If Speed +, CEMF ?, Torque ?

Back 54

CEMF + and Torque -.

if Speed +, It -.

Front 55

Pin (Power in) = ?

Back 55

Va x It (in Watts).

Front 56

Pout (Power out) = ?

Back 56

Speed x Torque x (0.1047)
RPM x ft • lbs x (0.1047)

Front 57

An increasing load increases Pin (Power in)...

Back 57

Load + = RPM - = CEMF - = Ia + = It + = Pin +.

Torque also Increases, Power out Increases.

Front 58

Armature Control

Back 58

Varying the Voltage, causing Ia to change, causing speed to change.