What is the (V/f) Factor in VFD (VVVF)?

Did you post this?

Synchronise speed =120f/p so if you vary the frequency speed is varied torque is proportional to square of voltage so we get a good torque variation also. Thyristor firing is done to get variable output.

V/F factor is the ratio to keep constant torque at higer speed to lower speed. In VVFD, Voltage is varied with frequency keeping this ratio constant so the MOTOR operates with contant torque. In physics formula, Power(P) is directly proportional to Torque(T) X Speed(N) i.e. (F). So to keep constant torque

T α P/F so T α (V / F) * I ( Where I is depend on mech. load)

So in VVVF drive, by keeping V/F ratio constant varying it is able to get constant torque or variable torque at low speed which is not possible in case of constant speed( i.e. without VFD)

Thanks gentlemen, I think you both have provided me fair explanations.

Thank you so much.

The guest is correct. Please look at the link given by me on #1

P = Tω correct

So

T = P/ω = k. P/f correct

ο V/f wrong

since I is not dependent on mechanical load VI cos Φ or power is what demanded by the load and not current.

conversion of mechanical parameters into electrical parameters is not so simple since the P itself is dependent on ω (check any load's operating characteristics)

The other guest (I don't know why he has marked himself OT) has pointed out, it is the magnetic flux density.

read the explanation given in the link of #1.