2006-07-08 23:39:21 · 6 answers · asked by its me 2 in Science & Mathematics ➔ Engineering
and why?
2006-07-08 23:58:22 · update #1
It will rotate slower , and use more amperage
2006-07-08 23:45:44 · answer #1 · answered by gjmb1960 7 · 0⤊ 0⤋
The most likely scenario is that the motor may not start and catch on fire.
The current into an AC induction motor is defined by:-
-its inductance
-its resistance
-its back emf
this is normally shown in its "equivalent circuit"
The low frequency would mean that its inductance is reduced by 33% (40/60), thus is start current would go up by 50%.
The starting of an induction motor is one of the hardest things that they have to do as there is no "back emf" generated by the rotation of the rotor magnetic field.
The normal start current is 6-8 times full load, thus this would now be 9-12 times full load.
As the power is equal to I squared, you can see that the motor will have 81 to 144 times more heating (normally 36 to 64 times) for the short start time.
Obviously modern variable speed drives put a varying frequency on a motor. this is normally done at reduce voltage ( to keep the volts per hertz ratio correct).
If you need to run this motor you will need to reduce the voltage.
It's torque is a function of its current, but its max Hp, is a function of the heat losses and how that is removed from the motor.
2006-07-09 04:53:08 · answer #2 · answered by poveym 1 · 0⤊ 0⤋
you are able to run a 440V 60 Hz motor at 50 hz grant.. Thr extra helpful way is to run the motor at 4 hundred volts or 420 volts. this may be executed by employing changing transformer faucets on your considerable substation transformer.major is the motor will run at a velocity below its score, 1420 rpm for 4 pole autos.
2016-12-10 06:50:50 · answer #3 · answered by ? 4 · 0⤊ 0⤋
approximately : we should increase the no. of turns of this motor winding by the factor 60/40 to give us same ratings of amperes and watts. if we did not do this .. the motor amperage will be high and the magnetic flux density will be less . so the speed of motor will be slower .
2006-07-09 00:07:16 · answer #4 · answered by u&me 3 · 0⤊ 0⤋
When the frequency is reduced than the speed by the equation af synchronous speed would be
N = 120*f / poles
f is frequency... hence you see the speed reduces with reduction in frequency... The voltage does not influence the speed it ofcourse determines the torque... hence as the voltage is same so is the torque...
2006-07-09 00:48:46 · answer #5 · answered by Seeker 1 · 0⤊ 0⤋
Can you say smoke & fire?
2006-07-09 02:27:00 · answer #6 · answered by cat_lover 4 · 0⤊ 0⤋