electric motor forward/reverse wiring?

According to William Wixon :
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That would only change which direction it starts -- assuming that one is connected to pin (3) and the other to pin (2) as shown in the "240dons.jpg" image.
First question -- just to be sure. You *are* connecting it to 240V aren't you? I'm not sure that the start winding would produce enough torque to reliably start it at 120V.
O.K. Time to do a bit of debugging. Are the motor wires push-on crimp connectors? If so, disconnect the motor wire from (2) and push it onto (1). Switch the motor on, and see if it starts. If so, note which direction, then stop the motor and move that same wire to (4) and switch the motor on again. If that spins up, check that it spins in the other direction. If you don't have push-on connectors, you will have to do a bit more work wiring it up -- or use clip leads for the tests, if you have those.
If it spins up, then the start winding is now proven to work, so it is in the wiring at the switch.
If it doesn't, use a meter to measure the power between (3) and wherever you have the wire connected.
That voltage should measure something near 120VAC. If it measures the right amount, and the motor still does not start on its own, then we have to check what has happened inside the motor. It could be that the centrifugal switch is not making contact, or the wires to the capacitor have slipped off their terminals under the bulge. (Or -- the capacitor was damaged during earlier tests when it did not spin up. Pull the bulge and look at the capacitor. If there is gunk inside the cover, or oozing out the end of the capacitor, it needs to be replaced.
However if it does spin up in the two earlier tests, you now need to measure the voltage coming from the switch to terminal (2). Measure that relative to terminal (3). That should be near 120V when the motor is switched on, and close to zero when it is switched off.
If you don't get that, it is a problem with the wire from (E) to (2), or the switch element which connects between (E) and (F) in the FORWARD and REVERSE positions. Check all of that wiring to see where you are not getting your power through. And measure the (E) to (F) switching (with the motor unplugged, of course) to make sure that the drum switch *does* connect them in both the FORWARD and REVERSE positions.
One other possibility -- is the switch upside down relative to the drawing? That is, the terminals which I have called (E) and (F) should connect both in FORWARD and REVERSE, while if you have exchanged ends on the switch, you will only get connection in the FORWARD position, (really terminals (A) and (B).
A pity that we don't have actual labels on the terminals for the drum switch, instead of the ones which I dreamed up to be able to talk about this.
So -- do your tests and let me know what you find.
Good Luck, DoN.
Reply to
DoN. Nichols
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Hi Don, Thanks again for your patience.
I assumed I was. Today I went out, plugged it in, flipped the switch and the dang thing strarted right up. Did it a couple more times and it started, then it started NOT starting. I probed the two lines in and one of them was dead. Probed it at the outlet and one was dead there too. Reset teh breaker and both were hot. Started the motor and started up, kept trying and it would start sometimes and wouldn't others. Probed teh wires again and one was dead again. Reset the breaker, started to realize that it was the breaker that was tripping. Thought it was internal problem with the motor. Finally noticed (to my great embarrassment) one of the hot lines going into the motor was touching the case. i had stripped just a LITTLE too much insulation off one wire and (to my great embarrassment) one of the hot wires was just barely touching the case, and of course, tripping the breaker each time i flipped the drum switch. eeek. Guess it's a good thing i had wired up the ground this time huh? So, now it starts but not 100% reliably. I guess that'll have to be something I'm going to have to live with. Seems to start right up like maybe 85% of the time, sometimes it won't start at all, some times it starts jerkingly. Sorry to have caused you to type all the below . Thanks very much for your patience. It sure has been a learning experience for me. It is fantastic to see this motor running there clamped to my workbench. It was fun to probe the wires in the switch. I was surprised to see, as you say below, one of the wires was "...close to zero.". Woulda figured it would either be 120 or ZERO. I assumed that must be juice remaining in the capacitor huh? I was probing, getting either 120 or zero and one time i got 220 and was like "wha' da frig?!", oops, probed the two hot leads. I woulda thought that woulda resulted in a flash and sparks. I think in the past that woulda been my indicator that i had done something wrong (as in the wire touching the case). If there was a bright flash and sparks then I knew i must've done something wrong.
Wow. So again, a BIG thanks Don. Whew!
b.w.
220 0 article Path: finder4.readnews.com!fnd01.iad01.newshosting.com!textbe01-ams!hwmnpeer02.ams!hw-filter.ams!hwmnpeer03.ams!hwmedia!news.highwinds-media.com!feeder.news-service.com!newsfeed.freenet.de!news.n-ix.net!Quza.UK.peer!nntp.gblx.net!news-feed01.roc.ny.frontiernet.net!nntp.frontiernet.net!news01.roc.ny.POSTED!53ab2750!not-for-mail From: "William Wixon" Newsgroups: rec.crafts.metalworking References: Subject: Re: electric motor forward/reverse wiring? Lines: 104 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-RFC2646: Format=Flowed; Original Message-ID: X-Complaints-To: snipped-for-privacy@frontiernet.net X-Trace: 52616e646f6d49564905afb1fe6043e9e75be528da7a78a38daaca11eaf138d5da4f56f5eccc8f8563ba650351566bea6df63113fccaa2ac75b3d239b2371194e0973c3069e3b356e1b50b7d4f2a6e5dca98091693999c2ea6ce452a0368f00871e28db1ec2181dec8ff07364a1bb4c5 X-Abuse-Info: Please be sure to forward ALL headers so that we may process your complaint properly. NNTP-Posting-Date: Tue, 18 Apr 2006 14:04:24 UTC Date: Tue, 18 Apr 2006 14:04:24 GMT Xref: finder4.readnews.com rec.crafts.metalworking:211628 X-Received-Date: Tue, 18 Apr 2006 07:38:57 MST (textbe01-ams)
"DHi Don, Thanks again for your patience.
I assumed I was. Today I went out, plugged it in, flipped the switch and the dang thing strarted right up. Did it a couple more times and it started, then it started NOT starting. I probed the two lines in and one of them was dead. Probed it at the outlet and one was dead there too. Reset teh breaker and both were hot. Started the motor and started up, kept trying and it would start sometimes and wouldn't others. Probed teh wires again and one was dead again. Reset the breaker, started to realize that it was the breaker that was tripping. Thought it was internal problem with the motor. Finally noticed (to my great embarrassment) one of the hot lines going into the motor was touching the case. i had stripped just a LITTLE too much insulation off one wire and (to my great embarrassment) one of the hot wires was just barely touching the case, and of course, tripping the breaker each time i flipped the drum switch. eeek. Guess it's a good thing i had wired up the ground this time huh? So, now it starts but not 100% reliably. I guess that'll have to be something I'm going to have to live with. Seems to start right up like maybe 85% of the time, sometimes it won't start at all, some times it starts jerkingly. Sorry to have caused you to type all the below . Thanks very much for your patience. It sure has been a learning experience for me. It is fantastic to see this motor running there clamped to my workbench. It was fun to probe the wires in the switch. I was surprised to see, as you say below, one of the wires was "...close to zero.". Woulda figured it would either be 120 or ZERO. I assumed that must be juice remaining in the capacitor huh? I was probing, getting either 120 or zero and one time i got 220 and was like "wha' da frig?!", oops, probed the two hot leads. I woulda thought that woulda resulted in a flash and sparks. I think in the past that woulda been my indicator that i had done something wrong (as in the wire touching the case). If there was a bright flash and sparks then I knew i must've done something wrong.
Wow. So again, a BIG thanks Don. Whew!
b.w.
Reply to
William Wixon
"DoN. Nichols" wrote
Huh, I was afraid i wouldn't. The link posted by Glenn...
formatting link
has illustrations with that kind of switching pattern but I guess that must just be an electrical schematic huh? :-( (pissed me off in that article the author says something like "...you're on your own..." (with the "alternate switching pattern", which of course MY drum switch has!)) (and i suspect every other drum switch manufactured in the united states also has.)
Yeah, when I was trying to create a mental picture of what I needed I thought "triple pole dual throw" switch, and tried to find it on on-line (mcmaster.com, etc) and couldn't.
I think your ascii got scrambled up.
I'd think that would've been easier than all this hassle.
Huh. For me I'd think "intuitive" would be forward/right, reverse/left. (or maybe that's the way the lathe that i had used in the past was wired and got used to that.)
-snip-
I don't konw. Jim posted this link...
formatting link
When i say "crappy" I'm not talking about it's electrical validity, just that it's SMALL and even if i enlarge it the details are blurry. I guess it isn't important that I be able to read "BU" or "BK" (or "WIRE NUT" or "SMUDGE") but coming from where i am, knowing nothing about electric wiring, I felt it would've been helpful to eliminate any ambiguity. (and i dont' think the drum switch in the drawing is the same as mine so that made it entirely more complicated, felt i was on a fool's errand trying to desipher that drawing.)
I do believe it can measure resistance, I don't know the terms, ohms, resistance, etc. I put it on the capacitor and it did what i read somewhere it would, pegged at one end of the scale and rapidly drop to near zero. It's an el-cheapo "Sperry", i stole it from Home Depot (i'm just kidding) (teasing Harold).
Huh. I was trying to find which one was the starting winding (i read the starting winding used thinner wire, trying to find which color wires went to the thin wires) but now I'm guessing the starting winding is obvious because it's the one with the capacitor and switch on it.)
OK, thanks.
oops.
Thanks. (Yeah, that's what i meant, 'C' and 'B'.)
Thanks. Yeah, this motor is w/o rubber bushing, my intent is to rigidly attach the switch to the headstock casting too.
Thanks again.
b.w.
Reply to
William Wixon
According to William Wixon :
That will do it. :-) Was it the case of the switch, or the motor?
Well ... if you hadn't -- the motor would have kept starting. But *you* might have lit up. :-)
Hmm ... this suggests that one of the contacts in the drum switch may not be making reliable connection. The contact might be burned from tripping the breaker through it so many times, or it might have been loose all the time. Check it out by operating it with the cover off and watching the switch in low light. Look for sparking were one of the switch contacts closes. (You're more likely to see the sparking when it jerks, but maybe also when it starts right up. Look at the contacts and see whether they can be made to make better contact by something like cleaning the contacts with a points file (one design of switch), or squeezing the contacts together a bit (if it is like a wafer in a rotary switch from electronics.
I'll bet.
Nope -- The two run windings in series are acting as an autotransformer, dividing the voltage by two. But it is not a perfect division, so it is likely to show a slight bit of voltage. That is why I told you to not expect a perfect zero.
Also -- wires running adjacent to AC-powered lines pick up a bit of voltage from capacitive coupling -- if they are not connected to something which has low impedance to ground.
And even neutral typically has a bit of voltage referenced to ground, because some current is going through it, and its resistance is not zero, so there will be some voltage there as long as current is flowing through that neutral -- and that can even be from something else plugged into the same line.
The meter is floating, so no, there should be no problem. Now, if it were a scope probe, which has a ground clip which is truly normally connected to the power ground, you could have blown more breakers. :-)
So -- this time you were doing something only slightly wrong. :-)
Glad to help.
I hope that you get your switch working reliably -- as it *should* start every time -- unless the centrifugal switch is not working reliably.
Enjoy, DoN.
Reply to
DoN. Nichols
According to William Wixon :
Hmm ... no -- I think that it is wiring of a double contactor to emulate that switching pattern.
Well ... the one on my Clausing is pretty much as yours is, but another which I have (of the sort which is used for the three-phase motor on a Bridgeport) is closer the kind shown in figures 5 through 8, and you can even see the cross-over wires if you look carefully. They are black insulated, and the switch body is a black plastic, so you don't see them at first glance.
That kind makes more sense to me -- because I don't have to analyze the wafers of the switch in the other to tell what it is doing.
They exist as toggle switches -- and even 4PDT -- but they aren't high enough current to reliably handle switching the motor live, only switching direction while it is stopped. And you would really want a 4PDTCO (Center Off) -- or you could not stop the motor.
I used a rotary switch designed for high currents -- gazillions of screw terminals.
I think that you were likely looking at it with a proportional pitch font -- which will scramble *any* drawing done in ASCII with a fixed-pitch font. And since different proportional pitch fonts are different widths for different characters, they don't all look the same, while a fixed pitch font, like Courier, will look the same on all machines. I see that there are some offsets put in by your quoting, so I'll fix them above, and you can try switching to Courier (or perhaps *printing* it with a fixed pitch font)
There -- it is back as it should be for the moment.
Except that it doesn't have the right kind of handle to really *feel* right.
What are the labels on your drum switch? I'll bet left is forward, right is reverse.
The big problem is that it is showing three mechanically joined, but electrically independant single pole double throw center off switches. You can't do that with your drum switch, though I could with the extra which I have -- after cutting loose the crossover wires and replacing them in the right pattern.
The circuit which I provided would work with any drum switch designed for three-phase motor reversing.
Ohms are the units used to measure resistance.
Sperry should be a pretty good brand, actually.
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Yes -- that is it.
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O.K. That should do it.
Good Luck, DoN.
Reply to
DoN. Nichols

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