Running a motor at overvoltage
Running a motor at overvoltage
(OP)
I've looked in FAQ and tried Search but this must have been covered before so if one of you kind people could point me to the answer it would be appreciated.
What exactly happens if you connect a 110V motor (say a small fan) to a 240V supply, and why?
Thanks
What exactly happens if you connect a 110V motor (say a small fan) to a 240V supply, and why?
Thanks





RE: Running a motor at overvoltage
Hot core may lead to stator winding insulation damage.
You are also challenging the insulation rating, although I think at the voltages you mention that wouldn't be a problem.
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RE: Running a motor at overvoltage
I can't see how it "may" anything... But rather "will" something.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Running a motor at overvoltage
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Running a motor at overvoltage
RE: Running a motor at overvoltage
Note, when you double the voltage on a resistor the proportionate increase in current is 400%. With a motor the increase will be disproportionately higher.
respectfully
RE: Running a motor at overvoltage
First split second:
An universal motor will rev up and perhaps explode from centrifugal forces, perhaps not. A shaded pole motor will start and run. A three-phase motor will start and run. A split phace capacitor motor will start and run. The latter three will run very close to sych speed.
Few seconds from start:
Most protective devices like motor protection and fuses trip.
Whithin a minute or two:
Embedded thermal protection trips.
After that:
Ashes and shrapnels. Not really because of the halving of life per ten degrees temperature increase but simply because everything gets way too hot and the universal motor probably cannot run at such a high speed for a long time.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Running a motor at overvoltage
http://www.easa.com/mo/TN-pdfs/TN08-397.pdf
Gunnar,
Shrapnel is already plural.
RE: Running a motor at overvoltage
Interesting link:
http://www.easa.com/mo/TN-pdfs/
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Running a motor at overvoltage
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Running a motor at overvoltage
But as gunnar mentioned, we don't know.
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Running a motor at overvoltage
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Running a motor at overvoltage
RE: Running a motor at overvoltage
old field guy
RE: Running a motor at overvoltage
Z = R+ jX
were R<<X
I = V/Z
Double voltage saturates the magnetic circuit, the core permeability “mu” approaches zero, and the reluctance of the magnetic circuits approaches infinity then the reactance X approaches zero. As a result, the impedance is almost same as the winding resistance Z = ~ R
I= V/R
The energy dissipated in the winding ( watts); W= I^2*R, will increase with the squared ratio of the new high current, leading to a premature insulation failure.
RE: Running a motor at overvoltage
"... premature insulation failure."
That kind of sums up my life...
RE: Running a motor at overvoltage
RE: Running a motor at overvoltage
Sounds like my buddy's diesel Olds.
He was pulling a steep grade with the car fully loaded.
1) A connecting rod broke.
2) It flew around and cut an inch wide slot out of the oil pan.
3) All the oil vented out the pan onto to road.
4) Then the rod punched thru the block.
5) All the coolant vented into the pan and out the same slot.
6) Then the rod came around and jammed in a thick web member.
7) The drive train stopped instantly. Leaving 45 feet of skid marks.
8) The drive train stopping that suddenly broke the cam shaft in half near the center.
9) The cam shaft launched forward shoving the sprocket thru the cam chain cover.
10) The camshaft also proceeded further in to the back of the water pump destroying it.
11) The sudden stop gutted the automatic transmission.
12) The gutted transmission sheared 3 teeth off the ring gear.
The CHP couldn't even push the car off the road. (hwy 17 at Lexington Reservoir)
I guess I could say the car had an coolant failure.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Running a motor at overvoltage
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Sometimes I only open my mouth to swap feet...
RE: Running a motor at overvoltage
The Olds Diesel is an excellent analogy for an electric motor run on increased voltage.
Same result; wallet depletion.
Mike Halloran
Pembroke Pines, FL, USA
RE: Running a motor at overvoltage
Your buddy has to look at the bright side: At least he this didn't happen on his honeymoon. (Sorry Keith, I can't let you forget that story.)
BK
RE: Running a motor at overvoltage
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Running a motor at overvoltage