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gmcf2004 05-31-2009 12:47 PM

Pool Motor Question...Please Help!
 
Recently, the bearings went in my pool motor. Because I am a novice at these types of repairs, I opted to buy a new motor & connect it to the old pump. I think I did everything right because when the pump/motor is connected to my pool lines, I am not seeing any water leaking into the motor. My problem lies with the start capacitor on the motor. The motor will start, but after a few seconds, the capacitor will burn out. I will see a white smoke and an brownish fluid leaks from the capacitor. Then the breaker trips. For the life of me, I cannot figure out what is causing this problem. I have gone through 2 capacitors already. Figured I would try this forum for some help. The pump is 220V and the setting inside the motor is set for 220V. Any help would be appreciated.

Yoyizit 05-31-2009 02:08 PM

If the RMS voltage across the cap when the motor is running is more than the cap rated RMS voltage, that's a problem. This would maybe be caused by a cap that is too low in capacitance value.

You could try running the motor with the pump disconnected. And compare the motor amps with the nameplate data.

That brown fluid might be a carcinogen.

micromind 05-31-2009 03:14 PM

The start switch is not disengaging the start winding. This switch might be a centrifugal one inside the motor, or a solid-state one in the connection box. It's supposed to cut power to the start winding at about 2/3 speed.

It's also possible that the motor is mis-connected.

A start capacitor is designed to be in the circuit for only a few seconds at a time. Any longer than a minute or so will cause it to burn up.

Rob

P.S. If the start winding doesn't disengage, the motor will draw about 4 time its rated current. Thus tripping the breaker.

gmcf2004 05-31-2009 03:21 PM

Micromind...thanks, I think you're on to something here. I think thats whats happening. The centrifugal switch remains engaged at all times. basically it is a spring loaded brass piece (2 pieces) with a notch at the top. The springs cause the notch to push against the switch. Not quite sure how to fix it so the contact is intermittent. If you're still here, what should I do?

micromind 05-31-2009 04:02 PM

A lot of times, a shot of WD40 will work. Sometimes the contacts weld together, they can usually be separated with a screwdriver. Sometimes the stationary contact backing plate is cracked.

There's usually an audible click and a visible spark when the switch opens on starting.

If you need to remove the back of the motor, first mark the front and back joints, so they can be re-assembled exactly where they were. A simple scratch with a screwdriver will do. Next, remove the 4 long bolts that hold it together. If it's a C or J frame (56C or 56J, etc), most of the time the bolts thread into tapped holes in the front end. Otherwise, there are nuts.

The ends are sort of pressed on. A lot of times there is a notch or two that a screwdriver can be used in to pry it apart. Pry a little bit on one side, then the other. Sometimes the end has tiny ears that are larger than the frame. Using a hammer and a screwdriver, tap on these ears, a bit on one side, then the other. If the motor is wired up in the end, be careful to not pull too hard on the wires when you get the end off. Usually, the frame will come loose from the front end, while the rotor stays locked into the front end by its bearing. You can remove the whole frame, and just leave the rotor stick out. Usually this can all be done while the motor is still bolted to the pump.

Now you can look at the start switch, contacts, etc. Work the switch by hand, it'll move hard, then suddenly easy. Sort of a snap type action. Make sure the contacts are OK.

When you put it back together, if the bolts aren't long enough to use to draw it up, you can tap the end lightly with a hammer. When you're done, turn the rotor by hand before applying power. Usually there's a cap on the end in the center that can be pried off, and the shaft usually has a slot cut into it. Turn it with a screwdriver. It'll be obvious if there's a problem.

Rob

P.S. I just noticed.....This is post #666 for me! (Eerie music playing in the background).....lol.

spark plug 05-31-2009 05:36 PM

Your technical advice leaves nothing to add. But the "superstitious" part is amazing. Also, I've heard that anything Asymmetrical is GOOD, while SYMMETRICAL numbers or shapes are to be avoided. There's PHILOSOPHICAL logic (if there is such a thing) to it. If something is Asymmetrical (uneven), we have to do additional work to perfect it. While Symmetrical (Even) shapes or numbers are PERFECT' and we can rest on our laurels... So to speak!!!

tribe_fan 05-31-2009 07:04 PM

Why not take the motor back on warranty ?

wirenut1110 05-31-2009 07:14 PM

Quote:

Originally Posted by micromind (Post 280900)
Rob

P.S. I just noticed.....This is post #666 for me! (Eerie music playing in the background).....lol.

Hate to add insult to injury but, prior to my post, this thread had 6 replies and viewed 66 times:eek:

micromind 05-31-2009 08:15 PM

Wow!!! When it rains, it pours!

I wonder what the statistical odds of this happening are?

And even more bizarre, we have the number 666, and the number 66, and the number 6. So we now have 6-6s.

Rob

MALCO.New.York 05-31-2009 08:34 PM

Quote:

Originally Posted by micromind (Post 280987)
Wow!!! When it rains, it pours!

I wonder what the statistical odds of this happening are?

And even more bizarre, we have the number 666, and the number 66, and the number 6. So we now have 6-6s.

Rob

If you remove the rear cover cap, the Centrifugal Contacts are Apparent!!!!

As one has said, WD40!!! Or parts Cleaning Fluid!



http://i212.photobucket.com/albums/c...aywardPump.jpg
http://i212.photobucket.com/albums/c...aywardPump.jpg

J. V. 06-01-2009 01:16 PM

It looks like your motor removal and subsequent reassemble went smoothly. Thats amazing. I usually recommend that DIY folks replace the whole unit. Pump and motor. This way you know it was assembled at the factory and the warranty will cover the pump and the motor. I suspect you did something when assembling or disassembling the pump motor. Next time replace the whole thing. Most people are lucky to get it all back together without issues.
Your problem lies in the switch or how its connected. Make sure you did not pinch any wires when putting it back together.

Yoyizit 06-01-2009 05:18 PM

Quote:

Originally Posted by gmcf2004 (Post 280857)
The motor will start, but after a few seconds, the capacitor will burn out.

I don't get how the cap burns out so fast.
Normally it would be in the circuit for a half second or so each time the motor starts, which is cumulatively many seconds over the life of the motor.
But if it stays on for several consecutive seconds it goes up in smoke? Maybe these caps should be fused. . .?

micromind 06-01-2009 07:59 PM

There are two kinds of motor capacitors. Starting and running.

Starting capacitors are designed to be in the circuit for only a few seconds. Usually, they have a rating of 1 start per minute, some more, some less. Most of them are rated for a maximum start time of 30 seconds or so.

Run capacitors are designed to be in the circuit indefinitely. These are the same capacitors that are used in HID light fixtures.

The main difference is in physical size and cost. A run capacitor of 10 ufd and 250 volts will have about the same physical dimensions as a start capacitor of 200 ufd and 250 volts. These two capacitors will cost about the same.

In a single phase motor that has proper overload protection, the overload will trip before the start capacitor is damaged. In the case of the start switch failing to break the start winding (and capacitor) circuit, the current will certainly be high, but not as high as locked rotor. The overload might not trip in time, and the capacitor will be destroyed.

Rob

Yoyizit 06-01-2009 08:34 PM

Quote:

Originally Posted by micromind (Post 281381)

A run capacitor of 10 ufd and 250 volts will have about the same physical dimensions as a start capacitor of 200 ufd and 250 volts.

Well, that's one clue. The surface area for dissipating internal heating for the start cap is not as much as for the run cap.
And if the start cap current is >>the run cap current the heating problem is worse.


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