ot electric motor

dieseldoc · Mar 2, 2011

what is a good 10 hp single phase motor that can run 3-4 hours and not get hot? I have been using baldor motors and they get to hot.

Bob · Mar 2, 2011

Baldor should be as good as it gets. Sounds like you MAY have low voltage issues or cooling fan issues.

Is it an open, drip-proof motor or a TEFC?

Jaden · Mar 2, 2011

Check amp draw to make sure you are not overloading it.

buickanddeere · Mar 2, 2011

Overloading or having VD will overheat a motor. What is the ambient temp of the motor location. Motor current and motor voltage? Wire/cable size, thermal overload size? Distance from utility transformer?

dieseldoc · Mar 2, 2011

voltage is good. its pulling 33 amps and the motor is rated at 40.The service to the barn is new 400 amp.Motor is about 10 ft from box and supply wires are bigger than needed.I bought a new baldor two weeks ago and it burned up today. The temperature in the room its in is around 50 degrees.

Joe in OH · Mar 2, 2011

maybe if you describe what it is driving, it would help determine what is wrong. Sounds to me like you either need a 15 HP motor, or you need to find whatever is causing a loss of efficiency. it may be time to look at replacing bearings, cleaning everything, etc...

Baldors website has alot of good info on it.

jbp · Mar 2, 2011

Had trouble similar to yours once. After spending quite a bit of money to find the problem, it turned out the transformer was the culprit. Have had no more trouble after the power company installed a new and bigger transformer. Good luck. Joe

Janicholson · Mar 2, 2011

As you indicate there is reliable clean supply of power, my answer is that what you are running with the motor is taking excessive power. My first move would be to assess the loads being placed on the equipment. Both operating loads, and idle running loads. If there is a bearing or shaft going bad or rubbing on other parts, the burn out might be expected. If the equipment checks out perfectly, and employees (or self) are not overloading it, I would put a 15 HP motor on the equipment. My off hand calculation is that 33 amps is too much for continuous load. My thinking is around 25 or less amps. 40 should be starting amps, and circuit breaker fuse rating. Put a shaft tach on it to see if it is close to RPM. if it is within 95% it should be OK. if more like 80 it will burn up readily. Jim

dieseldoc · Mar 2, 2011

All it does is run a vacuum pump so I can milk cows. It runs 3 hours continuous morning and night.The vac pump you can turn by hand and if its only pulling 33 amps and motor is rated for 40 I cant see why I would need a bigger motor. Also if the transformer or other electrical stuff was causing problems wouldnt all my other motors be giving me trouble?Transformer,main box and meter is all less then a year old. power company installed that when I built new parlor and upgraded my service to 400 amp.

Janicholson · Mar 2, 2011

This should make sense. Jim
Motor calculator

blinwmiaol.com · Mar 2, 2011

I don't know alot about electric motors but from your description, I would guess you have a pump issue, not a motor problem. You didnt say if you have a vein or lobe or what kind of pump you have but 33 amps steady draw on a vacuum pump seems excessive. I had a 200+ with a ten horse that only drew 20-25 amps. I would be interested in testing the pump by running it with the regulator removed to open the system, and then see what kind of a draw the open pump pulls. Just thinking of that size motor in a silo, ten horses drawing over 30 amps steadily is doing alot of work, moving alot of feed. I don't believe a pump should be working that hard just to make 13.5" of vacuum.

dieseldoc · Mar 2, 2011

its a sutorbilt lobe pump. Funny thing is i have two complete vac setups that way if one goes down i flip a switch and keep on milking. both have baldor motors on the pumps and they both run hot.I am not sure how to check the pumps but I would find it hard to believe both pumps are bad at the same time.The pumps turn real easy by hand so i can only assume that once they get up to speed they start working hard.

36 Coupe · Mar 3, 2011

A 5hp motor can draw 25 amps easy.

Mike Van · Mar 3, 2011

What's on the motor nameplate, TEFC, TENV or ODP? Motor voltage & amp draw should be there too.I don't believe anyone makes a 15 hp single phase motor, and a true 10 single phase has 38 - 41 FLA at 240 volt on the plate. I have no idea what that pump takes as far as hp needed to run it, the mfg. of the pump should be able to tell you.

olddog · Mar 3, 2011

Are these variable speed according to the vacuum level? Or do they run full speed and let air in to obtain vacuum level. I'm thinking of the rpms of the cooling fan(s) on the motors. Have seen them come unglued (heh heh) from the shaft. Are you running less than 14.5 inches of vacuum? 33 amps is just over the edge of 10 hp and does not allow for intransient loss along the way. Check all connections back to the pole. Are the pullys sized correctly? Got some milk cooling units blowing hot air on them or robbing them of cool air? Pumps gummed up with dried milk vapors or real milk if you jumped the trap(s) one time. Have you rinsed the sutorbuilts lately? Lotta hours on the pumps? VERY tight tolerances on that roots type blower, and just the slightest bearing wear will make them run hard at speed, even tho they appear to turn easy by hand when off.
Mebbe I've given you a few things to talk to your dealer about.

Sparktrician · Mar 3, 2011

How long did the motor before that last? If this one only lasted two weeks, you may have gotten a dud motor. I have seen that more and more lately. Also, I assume that your motor is on a motor starter, with overload (heaters) protection? Is this single phase or three phase? Dumb question, but....if three phase, you did connect the motor leads right (meaning if you have 120/208, you didnt connect leads for 480 configuration) You have a problem somewhere....not sure where though....

olddog · Mar 3, 2011

PS: "All... it does is run the vacuum pump".
I'd submit for consideration that the vacuum pump is/was the single hardest/longest working electric machine on the farm daily. Did you allow another hour each, morn & nite for washing or was that included in the 3 hrs? Mebbe another 15 minutes before milking for a presanitation cycle?
Or - another way to think about it, this used to be where MOST of your electric dollars on the farm were being converted to heat and other energy.

buickanddeere · Mar 3, 2011

Something odd going on. A 10HP single phase low efficiency motor without run capacitors draws 50amp on 240V. A new high efficiency/high power factor 10HP maybe as low as 40amp.
At 40 amp the motor requires #6 or heavier cable. 46amp thermal overload protection set point assuming the motor has a 115% service factor. Note some thermals get set for 40 to provide 46amp protection. Others thermals are set to 46amp to provide protection at 46 amps.
Short circuit protection in the main disconnect needs to be either 125 amp fast blow fuses, 70amp time delay or a 100amp breaker.
Overloaded or not, the thermal protection in the motor starter should provide burnout protection.
Any chance hot discharge air from the pump is blowing into the motor cooling inlet?
During milking times morning and night. It's peak demand on the utility grid and on your farm service. Voltage maybe fine mid day while trouble shooting but while milking. That motor maybe only seeing 200V. Demand from the pump while the milkers are running will differ from just running dead headed during a mid day test.
Any vibration issues?
Jan you sound more experienced and knowledgeable with electricity that 90% of folk here. I have seen an oops once however when a 240V motor was wired with one 120V and back to chassis ground.

dieseldoc · Mar 3, 2011

Well the dealers know nothing. They say eveything is fine and 33 amps is not to much. I am going to check into it some more. We hav the vac set at 12.5

dieseldoc · Mar 3, 2011

I checked everything at milking time near the end of milking so everything was warm.I am going to check the rpms like was suggested and I will post back.

Kentb of SWMO · Mar 3, 2011

Is the motor getting good cooling air flow. If you have the vacuum pump in a room that is enclosed that may not be getting enough cooling air causing the motor to get hot. Also look at the voltage at the motor when it is running. If you have a wire size issue, 33 amp needs at least number 8 wire. Larger if the motor is some distance from the breaker box. If you have LOW VOLTAGE because of the wire length, this could be the problem.

Kent

massey 333 · Mar 3, 2011

Welcome to the world of new electric motors,what you could do 5 yrs.ago now takes a bigger motor.If you are only pulling 33Amps.now,you aren't even loading the motor.As far as the heat,we have a motor shop that is now putting a second fan(pusher & Puller) on these new larger motors trying to keep them cool.By some of these other answers,just try Grain dryer motors that run 24-7 at full amps.++ for weeks-months on end.

teddy52food · Mar 3, 2011

I do a lot of recycling & scrapping. The new motors are wound with aluminum instead of copper. I think that may be the cause of more heat.

36 Coupe · Mar 3, 2011

Its time to measure voltage at motor terminal while running.Our 220 line measures 242 these days.Im on the end of a 12 year old three phase line.

dieseldoc · Mar 3, 2011

I checked rpms and it runs 1750 and the name plate says 1730.

JDseller · Mar 3, 2011

Baldor motors are "farm duty" I don"t know what they mean by that. My grain leg came with GE motors on it. They lasted 20 + years. Lightening struck the leg two years ago. The local grain equipment guy put Baldor motors back on it. THEY ARE JUNK. They did not last one season. I replaced them with new GE motors and have not had any problems.

Also what are you meaning by hot?? You can only touch 110-115 degrees without getting burnt. That is not that hot for mechanical stuff. Have you checked the temperature with a laser thermometer? Then you will know how hot it is getting. A lot of newer electric motors run in the 135-150 degree range. They are supposed to be more efficient. That I am not sure on being true but that is what the manufactures claim.

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