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What does VVVF stands for in VVVF drive ?
How does it differ from VVF drive?
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Answer Posted / rajashekhara p
variable voltage and variable frequency drives are purely
works on below formula
Ns=120F/P
Since synchronous speed is mainly depends on motor
poles,frequency and it's applied voltage but there is also
another factor which affecting to above formula that is slip
for example.
A 4-pole motor that is connected directly to 60 Hz utility
(mains) power would have a synchronous speed of 1,800 rpm:
If the motor is an induction motor, the operating speed at
full load will be about 1,750 rpm. This rotor rpm is
slightly less than synchronous speed since the method of
torque production for an induction motor is by the presence
of slip (a difference in synchronous speed and actual
mechanical speed). Otherwise there would be no induction
and therefore no torque produced. On the other hand, if the
motor is a synchronous speed, the rotor speed can only
match the synchronous speed independent of load.
If the motor is connected to a speed controller that
provides power at 50 Hz, the synchronous speed would be
1,500 rpm:
hence we can conclude this as vvvf is a variable voltage
and variable frequency.
| Is This Answer Correct ? | 10 Yes | 7 No |
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