I have an old delta 3 phase motor, 1hp, 220v, 1725 rpm. I have to give it a spin with my hand in order for it to start, whereupon it will speed up to a nice hum after a second or so. It will run in whatever initial direction I initially spin it in.. Any Ideas?
posted for all of us...
Yes
How many power wires? Black and red? Sounds more like single phase, to me. Though, I could be mistaken. I thought most 220 volt power supplies were single phase.
Does the motor have a run capacitor?
If he SAID it was a 3 phase motor, why are you doubting him (although you may be [probably are] correct at this point)?
He is there, and you are not. There are plenty of 208 volt and 230 volt 3 phase motors, but he did say 220v. sounds like a real old motor.
Yes, Spin it in the direction it needs to go. Try your foot next time. Bubba
You've either lost a phase somewhere or the motor is bad.
A properly powered and good 3 phase motor will start in the direction it's wired every single time. without fail.
Do you know how to test for such things?
Jake
It's been my understanding (though learning all the time) that electric motors (including, but not {necessarily} limited to HVAC applications {residential, light commercial [which is pretty close to residential] and heavy commeercial} and other devices a HO would service) tend to be single phase. Except for some commercial three phase equipment which I've not had the pleasure to service. Phase being defined as when the sine is going pos and neg. So, the 220 volts provided to homes around here is single phase. Though, I may be mistaken and there may well be new things to learn.
Can you really get three phase 220? I thought it was single phase.
Stormy........you really should STFU! You make yourself look dumber and dumber every time you open your cake hole. Bubba
How many wires you have coming out of that motor and what color are they, as is been said it sound like single phase motor and it needs running cap. or it has centrifugal start switch which is not working
3 phase motor will always start in same direction to reverse direction it needs reverse power two wires (phases) on input. From Dido
Chris...
Straight delta-delta 3 phase is common in the 220-240 area. 208 three phase is common in 3 phase delta/wye configurations.
That should give you enough information to Google it......
Three phase would be very common in any commercial building with a appreciable load.... office buildings, grocery stores... you name it.
Jake
Thanks. I've never worked with three phase, so it was a new term to me. I thought three phase started at 460 volts.
Jake: I have question for you since you are Electrician I have customer that I recently work for he have unit that has two 25 HP compressors and uses 440/3/60 which more or less is standard power, when I measure the supply source across the phases the supply I found 440 plus and minus couple volts which was some what reasonable then I measured it to ground and found surprise two legs (phases) are 440 to ground and one at ground potential: what kind system is this? Transformer is next to the unit From Dido
Dido,
Probably one of the variations of the 'open delta' design. It's a cheapo way of getting three phase for smaller loads.
Ground potential on one leg will 'wander' all over the place depending on the circuit load.
As an aside, particularly for Sam... I've seen several service bulletins recently describing repeated failures of VFD's on systems like this. At the very least, the drives 'nuisance trip' due to detected ground faults... and at the most the power sections fail because the internal control systems depend on a ground reference for proper phase symmetry.
I know Baldor was looking at this problem... so are Reliance, ABB, AB and others.
Jake
Thanks Jake, didn't know that...
OT Question... Is there a electrical text book you would recommend as a one or two book reference library? I have a few HVAC texts I use for reference (Modern Refrgeration, Tech Method, etc...) Is there a electricians bible or 101 text that you would recommend as up to date, accurate and detailed??? (I do have access to the 2005 NEC and some of the NFPA)
Thanks again, Joseph
Try these:
one or two book reference library? I have
etc...) Is there a electricians bible or 101
have access to the 2005 NEC and some of the
Joseph,
Depending on your interest and current understanding, ALL of the books by Mike Holt are strongly recommended.
Jake
Great stuff, Jake!
Thanks for the referral!
You're kidding, right?
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