Gaps in knowledge - Generators

Question 1

What output does a commutator produce?

Answer 1

Functions as a segmented slip ring, produces pulsating DC

Question 2

What is the output of a generator determined by?

Answer 2

EMF = Bvl
B - Magnetic flux
v - velocity
l - length

Question 3

In a generator, what winding is the output?

Answer 3

Armature

Question 4

What are some effects of DC ripple?

Answer 4

• flickering lights
• audible hum on intercom, PA, radios
• microprocessor circuits could fail due to unstable power

Question 5

How can DC ripple be negated? 3 ways

Answer 5

1- Lower amplitude
2 - Increase ripple frequency (easier to filter, less noticeable)
3 - Filters help eliminate remaining ripple (Stable DC)

Question 6

How do multi-pole generators increase performance?

Answer 6

• Eliminates zero voltage output
• Decreases amplitude
• Increases frequency

Question 7

How is the generator output controlled by field coils?

Answer 7

Vary field strength with current

Question 8

What are the 3 types of self exciting generators?

Answer 8

Relies on residual magnetism
- Series
- Shunt
- Compound

Question 9

How are generators rated?

Answer 9

In current
- since the output voltage is designed to its rated voltage.
- Direction of rotation as viewed from driven end - ARROW

Question 10

What is the coming in speed?

Answer 10

Speed at which it generates its rated voltage

Question 11

What are characteristics of a series wound generator?

Answer 11

• No current flows without connection to load
• Unstable at low load current (High load resistance)
• Voltage regulation = altering field current
• NOT USED IN AIRCRAFT - impossible to regulate as constant voltage is required