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Thread: Need help with motor starter
12-14-2010, 09:10 AM #1
Need help with motor starter
Can anyone help me figure out why my motor starter wont work like it should? I have a ge 3OO line control that I bought form graingers and it as never worked since I got it. There were no directions in the package and the box had been opened. After I tried to get it going and it would not work like I thought it should I went back to them to see if they had another one to see if there would be directions in another box but that was the last one they had and that I had probably burned it up by hooking it up wrong.
This is possible but I would like to know what is burned up and get it to working. I have spent days looking all over the internet and everywhere I can think of to find directions of how to test this thin. I remember when I bought this thing and it would not work I go around it by just hooking the line voltage and the motor leg together at the top of the contactor effectively in my view bypassing the control.
If I hook the motor leg to the T1 and T2 terminals at the bottom of the starter it will not work unless I manually push the spring loaded button on the coil. And when I turn it loose the motor stops. I can hook the motor le wires to L1 and L2 and when the pressure switch on the compressor calls for pressure the compressor runs like it should but isnít that bypassing the whole starter switch altogether?
12-14-2010, 09:20 AM #2
Pressure switch closes coil circuit which magnetically closes contacts on motor starter. I.E. the pressure switch sort of functions as a push button station on a machine tool.
12-14-2010, 04:50 PM #3
click here --->Full Voltage Starters - Product Information
GE also offers renewal parts for most of its major assemblies - but some documentation is needed by anyone - even a person well-versed with the product.
12-15-2010, 09:03 AM #4
12-15-2010, 09:07 AM #5
12-15-2010, 01:10 PM #6
12-15-2010, 04:07 PM #7
How do you have the coil circuit connected to the pressure switch?
Line wires to L1 and L2, load wires to T1 and T2.
There is a coil on the contactor, hopefully 120V. The hot side of the coil should be coming from the pressure switch, the neutral would go through the Overload block aux. contact to the other side of the coil.
This is a full motor starter, meaning it has an Overload Relay attached.You must have the heater element(s) installed and the OLR reset button must be pushed the first time to reset it, otherwise it will not work yet.
The wiring diagram is in the catalog, yours in on page 10 of this pdf. They are not going to give you a specific wiring diagram for your specific part number because all CR306 starters are going to be wired the same.
12-16-2010, 08:37 PM #8
Last edited by lin842; 12-17-2010 at 05:41 AM.
12-17-2010, 07:57 AM #9
A) the means by which you safely and reliably turn the motor on and off electrically (which can be replaced with a "manual motor starter") and
B) it is the primary protection device for the motor windings.
The only legal way to use a motor without having a motor starter with OL protection in it is if the motor itself has it's own thermal cutout switches embedded inside, a.k.a. "Kilxons". If it does, the nameplate MUST say on it "Thermally Protected" or Self Protected". If it does not, your motor may catch on fire before any upstream fuses or circuit breakers trip.
12-17-2010, 07:59 AM #10
I put a bunch of those GE 300 Line starters in service during the mid nineties, and coincidentally purchased them from Grainger. At the time, Grainger was only stocking them with dual voltage coils. These coils were a disaster; I lost I think three of them in the first month. After having one of the replacements fail, again, I got Grainger to replace them with single voltage coils. Haven't lost another one in fifteen years. The damned things would fail open; no smoke, no sparks, no smell, just an open coil.
The coils on the 300 Line are potted in epoxy, and there are no screw terminals on the single voltage coils; the wires went to terminals on the spring loaded retainers, which clipped over a half round metal detent on the potted coil. The dual voltage coils had additional terminals, IIRC, so that jumpers could be wired to put the two internal windings in either series or parallel as needed.
Check the coil you have for continuity. NOS single voltage replacement coils show up on e-bay all the time, but you need to make sure to get the proper size (00, 0, 1, etc) and voltage.
On edit: I see from the spec sheet that the same coil is used for NEMA size 00, 0, and 1; obviously larger coils for larger starters. The same spec. sheet / wiring diagram covers all the CR305, CR306, and CR309 starters, with a separate sheet covering the overload relay portion. I vaugely recall that the dual voltage coil had it's own sheet, which I likely pitched.
Next item of business... the thermal units in the overload need to be matched to the motor current.
12-18-2010, 05:30 AM #11
When I removed the compressor I took the starter that was hooked to the wall as well not remembering the problems I had with it when I hooked it up some years before. When I put it in my shop at home is when I realized it had been wired wrong all this time and why.
Not a major deal I can replace the coil in this switch and use it for something else later down the road. Tanks for the heads up on the safety issue.
12-18-2010, 06:02 AM #12
One thing I noticed is that this coil as two ground wires, pigtailed together, that come out of the front of the coil one on top and one on the bottom. They come out right beside the power wires. In all of my searching I have never found a coil anywhere that has these ground wires like this. Is this something that all of the dual voltage coils share or am I missing something?
I have already checked the heaters that are installed in the control and they are the correct size for what I am using it for, or was going to use it for that is.
Can you tell me what coil I would replace this one with? #?? Or, where to find a part #. Thanks Greatly!!
12-18-2010, 06:41 AM #13
There's a story about a guy who jumped off the top of the Empire State Building. As he whizzed past a 10th story window, someone yelled, "How's it going?" and got the response, "So far, so good!"
This topic and your comments remind me of that story. Don't take this wrong, but I think you have just enough knowledge on the subject to be dangerous. Jraef gave you excellent advice and I don't think you understood it. Motor starters have nothing to do with start capacitors or unloader valves. Absolutely nothing.
What you have here is a very dangerous situation. The fact that it sounds like you have gotten away with it for some time only makes things worse. You NEED the protection a properly installed motor starter provides, now more than ever. As electrical parts age, the likelihood of their failure increases. Centrifugal start switches, capacitors and pressure switch contacts have finite service lives. Compressors, even properly plumbed ones, are hard stating loads and accelerate the wear of these components.
When these parts fail, some may, in some instances, fail in a way that the compressor will not start or run, or fail in a way that causes things to overheat and burn up and very possibly start a fire. Others fail ONLY in the latter way.
You can get away with stuff like you are doing with something like a radial arm saw. It's obvious that the thing is on and when you aren't using it you will certainly turn it off. There's no way you will leave it on when you leave the shop. And, even if you do, it's running unloaded and will probably still be spinning away when you return. The biggest danger may well be if there's a power failure while you are working and then it comes back on in the middle of the night.
A compressor is like this in NO way. It starts and stops when it wants to, any time it's plugged in. If you forget to unplug it when you are through, and a component fails when the compressor starts at 2am, you may well find yourself standing on your front lawn watching the firemen roast weenies on what's left of your house. That's when you will fully realize the value of Jraef's sound advice.
I don't give this advice very often, but this is a classic case where you NEED to hire a qualified electrician to sort this mess out and get your compressor working right, with all of the necessary protections in place and working properly.
12-20-2010, 07:48 AM #14
I know sometimes it is hard to figure out just exactly what people are talking about what they write on a forum like this and Iím not the best explainer sometimes Ill agree on that. Iím wondering though, just how many of these home depot, harbor freight, sams club, compressors are out there in peoples homes and businesses that are not installed with the added protection of a starter box to run them on. It seems to me that if they truly needed these devices they would install them at the factories for fear of the possible law suits that would be happening all over the place.
Iím not saying these things should never be used Iím just saying that in this case it is a take it or leave it type thing for me. If the control was working then I wouldnít even posted this thread and it would be hooked up and controlling the compressor and everything would be wonderful. My problem was trying to figure out why it wouldnít work and in the realized it may not be needed and why spend $50 bucks on something right now if I donít have to.
Say, how is the view from up there? Oh, and watch that flag pole the Tea Party people have sticking out the window on the 9th floor on the way down that would be a real attention getter. Enjoy your flightÖÖ.
12-20-2010, 10:30 AM #15
I'm also sorry that I can't help with the single voltage coil part number; I don't recall you ever mentioned either the starter size or voltage requirement. All I can say about the dual voltage coils is they are a bad, but now very dim, memory, and any literature I had on them was tossed when they were returned. However, your description of the wire taps on the coils as "ground wires" indicates a general lack of understanding of how these things work. People here are always willing to help people learn, but are reluctant to provide advice that may put someone in danger, and rightfully so.
Your best course of action is to keep searching for the literature on the 300 Line starters, after having determined the starter size, (from the data plate) and the voltage requirement of the coil. If you are powering this line to line, then I assume that would be 230V if this is a typical US single phase residential situation; 115V if there is a control transformer involved.
The detail code at the end of the part number isn't going to do much good unless you have access to the full GE catalog that was current at the time the equipment was produced.
12-21-2010, 06:55 AM #16
In the past most all commercial property was wired 3 phase but not any loner in fact its hard to get three phase service unless you are in an industrial zone or really put the sales job on the electric company and make your point that you need this type service. I had to almost beg them when I wanted 400 amp service installed at my house when I built it.
The business location I removed the compressor from at one time had 3 phase current but about 20 years ago the buildings were remodeled and the permits required that the service be changed to single phase because we were not using enough juice to justify it. When I took over the building 10 years later I just used the equipment that was there because my compressor was the same compressor the other guy had, a Black Max 6hp 80 gal. that came from the price club.
My thinking on the line control was it would be better because I was doing a lot of sand blasting until that part of my business went south with the economy and then the compressor would run almost non stop all day. But then I realized once I took it out, the way it was wired the control was basically bypassed and not doing anything at all anyway, so why even bother?
And no I didnít change the motor, its still like it came out of the box. I think we have a disconnect here a little bit in the communications dept. LOL Once I realized the coil was bad on the control I decided to forget about it for now since it had been working like that nonstop at times every since it was installed anyway. If the economy comes back and my powder coating business comes back I will probably get some different kind of setup as the need arises.
Oh, by the way. What are the two black wires that are pigtailed together coming out of the coil? I have looked at hundreds of different coil set ups and none of them show these wires like this. I tried calling ge but that was a joke and they didnít return my e-mail. Thanks again for the help.
12-22-2010, 03:46 AM #17
Just a guess, but the wires that are pigtailed could be
the coil ends. Tied together on a 120/240v coil, that
would make it wired for 240v operation. Can't comment
on GE coils, except that the only problems I have ever
encountered on dual-voltage coils is that some mullet
wired the 120v winding to a 240v control system.
One of the reasons I have always preferred SquareD -
the terminals are clearly marked, and if wired wrong,
it is obvious that it was mis-wired (coupled with the
fact that it used a center-tapped winding; less wires
to contend with in a cramped starter assembly).
12-22-2010, 07:21 AM #18
No disrespect intended, I understand your situation now, this is mainly for posterity.
I’m wondering though, just how many of these home depot, harbor freight, sams club, compressors are out there in peoples homes and businesses that are not installed with the added protection of a starter box to run them on. It seems to me that if they truly needed these devices they would install them at the factories for fear of the possible law suits that would be happening all over the place.
I’m not saying these things should never be used I’m just saying that in this case it is a take it or leave it type thing for me. If the control was working then I wouldn’t even posted this thread and it would be hooked up and controlling the compressor and everything would be wonderful. My problem was trying to figure out why it wouldn’t work and in the realized it may not be needed and why spend $50 bucks on something right now if I don’t have to.
It's also important for the forum as a relatively permanent document that this information be brought up and not left uncorrected or unclear, because unfortunately someone else may read your comments and ASS-U-Me that it is perfectly fine to plug a 230V motor in directly without concern for overload protection. The big picture point in all this is, it is not. You MUST know what you are doing and what you are working with. Assume nothing, take nothing for granted when it comes to electricity.
12-22-2010, 07:26 AM #19
Just for reference (and because I forgot about "impedance protected" motors:
Motors that start automatically (i.e., thermostat controlled) and are located out of operator sight must be protected against dangerous overheating due to failure-to-start or overloading. This protection may be a separate over current device (i.e., motor starter) complying with Article 430 of the National Electric Code (NEC), a thermally protected motor (internal motor protection), or an impedance protected motor.
Basic types include:
* Automatic-Reset (Auto.)After motor cools, thermal protector automatically restores power. Motors with automatic reset thermal protection MUST NOT be used where automatic or other wise unexpected starting of the motor could be hazardous. Applications where automatic restarting could be hazardous include compressors, conveyors, power tools, farm equipment, and some fans and blowers. Where such a hazard exists, always use a Manual-Reset thermally protected motor.
* Manual-Reset (Man.) An external button must be pushed to restore power to a motor. Preferred where unexpected restarting would be hazardous, as on compressors, conveyors, power tools,etc.
* Impedance or Impedance Protected(Imp.) Motor is designed so that it will not burn out in less than 15 days under locked rotor (stalled) conditions, in accordance with UL standard No. 519.
12-22-2010, 07:53 AM #20
The GE 300 Line coils seem to have been designed to provide a robust, "solid" part with no wires to come loose. The wound coil was attached to its termination, which was also the mounting, and then the whole thing was potted in epoxy or something similar.
To make a dual voltage version, GE cut the winding in half, and brought the two cut ends out as wire pigtails. Spliced together, they put the two windings in series, for high voltage use. Attached to the wire termination of the end of the other winding, they put the two windings in parallel, for low voltage use.
There is nothing inherently bad about this system, just that several I had failed prematurely, most likely from a manufacturing defect hidden when the windings were potted. Given the information in the first post, I suspect the OP has one of these coils, and that it has failed, the same as mine did. If the OP were to do a continuity test on his coil, I bet that at least half is an open circuit. Even if the one of the two windings is still intact, both are needed to provide a strong enough magnetic field to reliably hold in the contacts and provide chatter free operation. So, he needs to source a replacement, and he needs to decide which voltage it should be rated for.
Here's a link to the GE brochure for the 300 Line controls, with photos of the contact block and their "wireless" potted coil.