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amith
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India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

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About Induction Motor

08/16/2011 12:49 AM

Good day!

If i select the Induction motor of 3Ph, 4 pole, 1500RPM, 32 KW & variable frequency drive..,

& If i run a motor at 500 RPM using drive, Is it possible to get 32 KW of output...

With regards,

Amith Raj
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lyn
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#1

Re: About induction motor

08/16/2011 12:52 AM

No.
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Tornado
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#2

Re: About induction motor

08/16/2011 12:53 AM

NO!

(Well, only for a short time, maybe.)

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amith
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#3

Re: About induction motor

08/16/2011 1:09 AM

Ok thanks...

It will decrease because Power=(2*pi*Speed*Torque)/60.....

Another doubt is, As induction motor specified at 1500 R.P.M, if we run at 500 R.p.m what is speed torque characteristics..? will it be same proportional as standard or Will it vary at low speeds...?
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lyn
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#4
In reply to #3

Re: About induction motor

08/16/2011 1:18 AM

If you have selected a specific motor and have the performance characteristics of that motor, why would you need us????

I can be of no further useful help. Wait, that implies that I was previously of useful help.

I don't care any more, I just had two shots of Gran Patron Platinum. My cursor may start jumping again.
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amith
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Location: India
Posts: 69
#5
In reply to #4

Re: About induction motor

08/16/2011 1:24 AM

Untill now i have not purchased the motor, I am telling that If i select...........

I am trying to clear my doubts on Induction motors...

I want to know that, Is the same motor is good performer at low speeds..?

&&& i am also checking the Possibilities that Can Induction motor is used as load for other motor..?
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lyn
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#6
In reply to #5

Re: About induction motor

08/16/2011 1:31 AM

Electrical Motor Efficiency
Look at this↑, call me in the morning.
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amith
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#7
In reply to #6

Re: About induction motor

08/16/2011 1:36 AM

Your number is not in use...
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Anonymous Poster #1
#8
In reply to #5

Re: About induction motor

08/16/2011 1:47 AM

1. The VFD usually generate constant torque so that takes care of your power requirements (it will be of course variable power)

2. The Speed-torque characteristics will remain similar (not same) but scaled down according to the synchronous speed (new) and the torque (new)

3. Motor can be used as a load for another motor (of course in the form of and Induction generator not motor)
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lyn
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#9

Re: About induction motor

08/16/2011 1:53 AM

I have run aground. Must wait for the tide.
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Tornado
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#10
In reply to #9

Re: About induction motor

08/16/2011 2:09 AM

•••

(Three black balls = nautical signal for having run aground. Better in sand than on rocks.)

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msamad
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#11

Re: About Induction Motor

08/16/2011 6:12 PM

For VFD driven motor, ideally the

(1) The Voltage is proportional to Frequency (maintains constant V/F ratio) up to the rated frequency (or rated voltage)

(2) Torque is constant up to the rated frequency and then decreases

(3) Power increases up to the rated frequency and then constant

(4) Motor rated power and rated speed are obtained at rated voltage

(5) And off course, the motor speed is proportional to motor frequency.

Up to the rated frequency, the torque is constant. From the speed-torque-power equation (HP = Torque x Speed/5250), the motor output power is proportional to the speed or frequency or voltage up to the rated voltage.

For your case, you may expect (32 x 500) / 1500 = 11 KW (approximately) output from the motor at 500 RPM.

- MS

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