Answer / uditparashar

v/f control means controlling the motor with constant torque by varying the voltage (V) or Frequency (F) as torque is proportional to ratio v/f

HELLO EVERYONE, I RECENTLY HAVE FOUND ONE PROBLEM, I WAS TAKING NO LOAD TRIAL OF AN HT MOTOR 920 MOTOR , 1440 RPM , 6.6 KV, WITH AUTO TRANSFORMER. AT 450 V, LOAD WAS 40 AMP AND SPEED WAS 250 RPM. BUT AS WE INCREASE VOLTAGE FROM 450 TO 480V, LOAD BECOME 41 AND SPEED REDUCED TO SOME RPM . SO WHICH PHENOMENON ACTED HERE FOR REDUCING SPEED.?? AND IS IT HAPPENING ALWAYS OR IT IS RARE? I ALSO HAVE FACED SUCH PROBLEM WITH FEW LT MOTOR ALSO.

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