Medium Voltoage Motor Rotation Check
Medium Voltoage Motor Rotation Check
(OP)
I have a 4160 V 1000 HP Motor I want to check the rotation on. However we recently had a failure and would prefer not to do a bump test. Is there another solution?





RE: Medium Voltoage Motor Rotation Check
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Medium Voltoage Motor Rotation Check
Do you have any Idea of the amount of voltage we can get out of this motor? It has been sitting for 2-3 months. Also what would it do if we hooked up 480 V to this motor while it was uncoupled? Thanks for your help
RE: Medium Voltoage Motor Rotation Check
Safer, clean and cheap.
RE: Medium Voltoage Motor Rotation Check
Amprobe Model MN1604.
It test the line 3-phase sequence or the de-energized 3-phase motor leads squence for a desired motor rotation.The rotor is test rotated by hand.
http://www.amprobe.com
RE: Medium Voltoage Motor Rotation Check
http://www
RE: Medium Voltoage Motor Rotation Check
RE: Medium Voltoage Motor Rotation Check
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Medium Voltoage Motor Rotation Check
I have no idea what voltage you get. It depends on remanence and how fast you rotate. Most recorders work down to millivolts, so you should be able to see the phase sequence. There is no risk that you get hundreds of volts.
Connecting 480 V is a very good test if you run uncoupled. I would call that a "bump test" and you said you would avoid that. But, of course, at 480 V, you get about 1 percent torque - so the "bump" will not be very "bumpy". You may even find that the motor doesn't start. It depends on what bearings you have. But you will absolutely be able to find out rotation. Just turn the shaft. The way it turns easier is the way it will rotate when you connect 4160 V.
I like the Amprobe tester that aoalde referred to. But (I know that you will not do it, but have to say it) do not test the 4160 V with it. It will explode.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Medium Voltoage Motor Rotation Check
RE: Medium Voltoage Motor Rotation Check
Very clever. A PLS for you!
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Medium Voltoage Motor Rotation Check
Don't you mean you will explode?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Medium Voltoage Motor Rotation Check
My guess; All of the above!!
LOL
Respectfully
RE: Medium Voltoage Motor Rotation Check
RE: Medium Voltoage Motor Rotation Check
An induction motor could become a generator. On a rough estimation, it will require full field intensity and full speed (assume 890 rpm) to generate 4160 Volts. Induced voltage will be reduced proportional to flux and shaft speed.
If we are lucky the residual magnetism will be 1% of the nominal and by hand you barely will get 10 rpm.
The expected voltage will be; V = 4160 X.01X10/890 = 0.467 Volts.
RE: Medium Voltoage Motor Rotation Check
Let us know how your tester performs.
Thanks.
RE: Medium Voltoage Motor Rotation Check
As it happened, this motor was doing CW rotation when connected A - B - C (or L1, L2, L3 as we say in EU). The voltage is no more than around 100 mV RMS. A larger motor and/or a higher speed will produce higher voltages.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Medium Voltoage Motor Rotation Check
RE: Medium Voltoage Motor Rotation Check
Respectfully