Bottom line: I'd sure rather have Jake, Paul, or even Precision Machinist wire my shit than have you do it Volts. My guess is that you studied Electricity at the "Tom Pendergast Institute of Pedophilology and Copper Pipe Fuses".
Volty, Volty, Volty.....
I 'assumed' because the man asked a question. Notice in the original response I said 'probably' and not what the system DEFINITELY was... as you have done.
I don't know... and neither do you. I made a WAG that I think is a much better choice than yours. Nit pick it all you want...
It remains unlikely that someone would install a closed delta for such a small service... and it's even more unlikely that an older corner-grounded delta scheme is being used.
Yes.. a closed delta is much more stable... and more expensive, too. Maybe you'd want him to install six phase and be really clean and stable?
... to run a couple of three phase 25 horse compressors... an open delta design is more than adequate and efficient.
Just so you know... I never recommend open deltas to my customers... I don't like them for the capacity problems and the 'wild leg' scenario. But for quick, dirty and cheap three phase drops... who can argue?
Jake
PROBABLY because you don't know what it is.
I know exactly what it is, you were the one who was speculating. Go ahead ask the same question over in Mike Holt's forum, where all can see, and you'll get CORNER GROUNDED DELTA.
Stop yer f****ng whining, Jake. Now is the time to be a man and fess up that you were wrong.
It's not a service. He clearly stated that the xfrmers were next to the units. More likely that the building service is a lower voltage and they needed to step it up for that particular equipment.
man, you are some f****ng stubborn son o' bitch! and a picky one at that. Well, so am I, but I'm old and grouchy, so its OK for me. Faaaarrrrt!
Bob
Thanks everybody for your responses. It IS a 3 phase, nine wires comin out of it. An ancient 'bullet' motor from an old unisaw, 1940's I think. I completely disassembled it, and discovered a broken wire, so some of you were right, its wasn't gettin 3 phases. It works like a charm now, and my 1st 3 phase wiring job turned out great, mainly because I'm still alive!!
There were 9 wires, all black cloth! I think it could be wired for 220 or 440. One of the wires was cracked [super ol;d] inside the motor housing, so it WAS only getting 2 phases. It IS a 3 phase though, sorry about the confusion, I fixed it the next day and have'nt been checkin in with you all. It works great now, super smooth but a little too much vibration. Can you balance these @ home or in the shop or do you need specialized equipment? Its going in a table saw, can't have it vibrating. Also, can anyone explain the difference between delta and Y 3 phase systems? Are they a means of transmission? I just wired my first 3 phase from my box in my shop, understand enough about it, but would like to know more.
thanks
Excellent. Glad you got it fixed.
Well, sport, like it or not, you aren't dealing with a 3 phase motor anymore.
Either you aren't providing three phases OR it has an open winding.
The outside connections may be delta but if you lose on winding with a true delta connection you still have two true phases and the machine will not want to run backwards.
Likely the motor is "star" wound inside and one winding is open. The other two windings are in series and only see one phase.
A "quick and dirty" check is to measure the current in all three phases after you have started the machine. I suspect one phase shows zero current.
>
Oh, Boy... you've really hurt my feelings.....
I think I'll cry on the keyboard a while...
SOB SOB SOB.....
Lookit, Volty... it isn't corner grounded. The fellow who asked the question confirmed that earlier in the thread....
Go ahead and ask over at Mike's forum. I don't wanna waste their time....
Professionals will say 'probably' and 'maybe' a lot in Usenet. As I said, I don't know... and neither do you.
Oh, my eyes are tearing up again... gotta go.
Bwahhhhhhhhaaaaaa!
Jake
Every 9 lead motor I have worked with, and I've worked on LOTS of them in my industry is a dual voltage Y wound motor ,configurable as a series Y for high voltage or parallel Y for low voltage operation. .
3 of the leads are connected to a factory made Y node and the other 6 leads are from the remaining 3 windings that are each connected in series with the factory Y node lead or connected together to form another Y which is then connected in parallel to the factory Y node to the 3 phase power.In every case, whether the motor is connected to a Delta power system or a Wye power system, if one phase has no power , the motor would single phase and the current drawn by the motor would cause the overloads to trip in a rather short time.
I have never seen a 3 phase motor be able to be spun in either direction by hand to "kick start it" and continue to run happily along in that direction.
I have seen high voltage configured motors connected to the lower voltage power and see them run with very reduced torque capability.
I have not worked with too many appliance type motors with multiple leads, but I have done some.
Something is odd here for sure.
Bob
You could take a look at this link...
All transmission that I'm aware of is delta... three phases and no neutral.
A wye has a neutral... and is more common in distribution systems.
Wyes are used a lot for dual-voltage purposes. Take a 460 volt wye. It is usually fed from a higher voltage delta... and transformed into 460 wye. Basically, there are three power legs (the legs of a "Y") and a center connection that is grounded at the transformer. Between each 'leg' you get 460 volts. Between any "Leg" and the center connection you get 277.
A smaller wye is usually 208 volts leg to leg. Any leg to the center connection will give you 120 volts.
The "wye" gives power for lighting and other circuits in a facility.
Straight Delta-Delta transformers are commonly used to supply large industrial facilities or single point-of-use circuits (big furnaces/motors/etc).
Relating this to your motor problem, here's my quick-check for 3 phase motors..
Bob,
They'll do that (manual kick start) if a inter-winding connection is open... particularly on a nine-lead running lower voltage connect.
We had a perplexing deal one time on a vibratory conveyor... a rock crusher, as I recall. The thing bounced several tons of rock on a bed until the smaller stuff fell through plates in the bed.
Man, that thing was noisy.
Anyhow.. calls on nutty OL trips and occasional blown fuses. Go out and measure with the equipment sitting still and all was well. Meters measuring current draw while the machine was running looked OK.
In the end, we used a PQA and looked at what was happening over very short time cycles. One phase was going LOW... drawing the others HIGH.
Tore the peckerhead apart and found it packed with some special anti-vibration compound. It kinda looked like silly putty but a lot more expensive.
Anyhow... two leads on the motor were partially broken near the motor potting. Had her re-leaded and all has been well ever since.
Jake
Hi Jake,
That's interesting; I have to try a 9 lead motor and disconnect one winding. The only way I can think it may work at all is if it is configured Parallel Y ( YY) and one Y is only connect to all 2 phases and the other Y remains connected to 2 phases. I am curious enough to try it when I get a chance. Intermittent stuff like your example is tough to find unless your record it. All the motors my company uses (well 95% or so) are European made and have brass strap jumpers to configure the voltage setting for the motor. Our older equipment had lots of 12 lead motors for 230 or 460 AND Y/delta switching for soft starts either way. biggest of those was only about 15HP
I used to work in a concrete pipe factory for a few years in the 70's, so I know from noise!
Bob
Thanks for the links, much appreciated, been looking for a straight forward tutorial with practical information about common 3 phase motor wiring diagrams all over the internet. shoulda just asked that from you guys straight out.
This motor only pulls 2.8 amps @ 220V. Is it nessecary to buy 3 new breakers, or can I just plug into a stack of low draw 15 A 110V breakers? Or should they be lower amperage breakers so as not to smoke the motor in the even of a short. Do they make 1A breakers?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.