Alternating Current Theory
List the essential parts of a transformer?
Primary Winding Secondary Winding Iron Core
What does a three phase power supply provide in an induction motor?
A rotating magnetic field
Transformers can only be applied in what circuits?
AC Circuits
A turbine that operates at variable speeds uses what?
An asynchronous generator
What does a transformer do?
Changes or transforms alternating voltage to any desired value
Inductive influences from from what?
Coils of Wires Motors Generators
Hertz represents the number of what?
Cycles completed per second
What converters are used in variable speed wind turbines?
Frequency Converters
What is Magnetic Induction?
How a transformer transferred energy from one magnetic winding to another.
The "Z" of an AC circuit is the what of the circuit?
Impedance
What device converts DC to AC power?
Inverter
Electrical Motors convert electrical energy into what?
Mechanical Energy
What are the typical grid frequencies for North America and the rest of the world?
North America=60hz Rest of the World=50hz
When looking at a sine wave in AC voltage, a cycle is represented by what?
One positive and only negative alteration
3 basic properties of AC voltage are?
Period of Time Frequency Amplitude
Apparent power is calculated using the circuit impedance which includes what?
Resistance and Reactance
What is the difference between the field of the stator and the mechanical rotation speed of the rotor?
Slip
What part of the generator is always connected to the grid?
Stator
What is Power Factor?
The value that represents the amount of phase shift between voltage and current
What is generator slip important?
To keep the generator rotor filed synchronous with the grid at varying speeds
Why does the generator shaft encoder send signals to the frequency converter?
To maintain synchronization of the rotor and stator
A transformer can step voltage up or down. T or F?
True
Transformers have two of these that are not physically connected to each other.
Two windings
Reactive power in an AC circuit is what? and Creates what?
Un-Usable and Creates Heat
In AC power what are constantly changing?
Voltage and Current
A three phase generator has three single set of what?
Windings