Introduction To Synchronous Motor :
•Constant speed fixed by system frequency
•DC for excitation and low starting torque
•suited for low load applications
•Can improve power factor
•suited for high electricity use systems
Synchronous speed (Ns):
 |
| Synchronous Motor |
•Constant speed fixed by system frequency
•DC for excitation and low starting torque
•suited for low load applications
•Can improve power factor
•suited for high electricity use systems
Synchronous speed (Ns):
Ns = 120 f / P
Where. Ns--Synchronous speed
F- Frequency
P- No of poles
Principle
A synchronous motor is an AC motor, which runs at constant speed fixed by frequency of the system.
It requires direct current (DC) for excitation and has low starting torque, and synchronous motors are therefore suited for applications that start with a low load, such as air compressors, frequency changes and motor generators.
Synchronous motors are able to improve the power factor of a system, which is why they are often used in systems that use a lot of electricity.
This motor rotates at a synchronous speed, which is given by the following equation
Ns = 120 f / P
Where:
f = frequency of the supply frequency
P= number of poles
Working Of Synchronous Motor Or Generator
•Synchronous machines employed to convert electric energy to mechanical energy
•To present the principles of Synchronous motor, a 2-pole synchronous motor considered
It has the same basic speed, power, & torque equations as Syn. Gen.
•Syn. Motor is the same in all respects as Syn. Gen., except than direction of power flow
•Since the direction of power flow reversed, direction of current flow in stator of motor may also be reversed
•Therefore its equivalent circuit is exactly as Syn. Gen. equivalent circuit, except that the reference direction of IA is reversed
1) Synchronous condenser is a synchronous motor with
a)Over excitation
b)Under excitation
c)Normal excitation
d)All of the above
2) Synchronous motor is a
a) Constant speed Motor
b) Variable speed Motor
c) Adjustable speed
d) None of the above
Comment Your answers below .......
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