Unit 1-11 Flashcards
What are the two main types of AC generators?*
TYPE 1 - Constant RPM generators
TYPE 2 - Variable RPM generators
What are the two types of constant RPM generators?
Constant Speed Drive (CSD) and generator
Integrated Drive Generator (IDG)
What is KVA?
Kilo-volt amperes
A unit of apparent power
Describe the constant speed drive (CSD)*
Where is it installed?
Frequency?*
Separate unit from the generator
Between variable speed engine and constant speed generator
400 Hz
Describe the integrated drive generator (IDG)*
Frequency?*
Integrates the generator and speed control into one unit
400 Hz independent of engine RPM
How is an integrated drive generator (IDG) better than a constant speed drive (CSD)?
Reduces weight and size
Higher RPM/higher power output
Higher alternator speed
Improved cooling features
IDG and GCU are considered as _____ _____ _____
Line replaceable units (LRU)
Do variable RPM generators need a constant speed drive? Why?
No constant speed drive needed
Less mechanical stuff to break
What are the types of variable RPM generators?*
Variable speed constant frequency (VSCF)
Variable speed variable frequency (VSVF)
What is the frequency output of a variable speed constant frequency (VSCF) generator?*
What changes output in this system?
Constant 400 Hz output
Solid-state circuitry
List advantages and disadvantages of variable speed constant frequency (VSCF) generators
Advantages:
No CSD required
Smaller / Lighter
More versatile installation (no CSD & electronics can be mounted anywhere)
Disadvantages:
Relatively low power output
Not as proven through long term use – reliability, operating cost
What is the frequency output of variable speed variable frequency (VSVF) generator?*
Output frequency changes with engine RPM
