March 809 Motor Capacitor/Disassembly

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ImMrAwsome

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I have a March 809-PL-HS. It seems to have lost most of it's power. When I plug it in, it just buzzes and heats up. I took off the pump part to take the load off of the motor. When I plug in the motor, and spin it by hand, it takes off like normal. When I hook the plug up to my multimeter, the resistance jumps all over the place.

Looking around the internet, this seems to be the symptoms of a bad capacitor. So...
A.) Does this motor even have a capacitor?
B.) Has anyone successfully gotten the motor out of the enclosure?

Thanks
 
The capacitor is usually located under a metal cover that is on top of the motor. It's easy to spot. Caps are dangerous , and you need to discharge it before removing it.
 
My pump doesn't have a metal cover, or one of those boxes attached to the side. Does that mean I don't have a capacitor?

Looking inside the motor, I see a silver box-shaped thing.

Pump Guts1.jpg
 
I'm not sure what the arrow is pointing at, but if that is a capacitor, it's for noise, not starting.

I looked at a March 815 assembly diagram and if there is a start capacitor it has to be inside the cylindrical housing itself. And it would be big enough to easily notice - that arrow isn't pointing to anything that fits that bill.

It wouldn't surprise me that there is no start capacitor in these motors...

Cheers!
 
I have an 809 HS and it has quite a bit of momentum/power when starting up. From the outside I can't see a capacitor inside the housing, or even the room for one.

Measure the resistance of the coils. I measure around 9.0 ohms across the plug (analog meter).

Once you start it with a hand spin, does it have power? If not, there maybe excessive friction on the bearings or a burned out coil/loose wire.
 
The resistance across the plug jumps all over the place, which is why I thought it would be a bad capacitor.

The only way I can hand spin the motor to start it, is with the pump off. So, I hand spin it (it then works fine), and then I place the pump housing over the spinning magnet, and it works fine.
 
I doubt this motor has a starting capacitor, given its size. Curious, does this motor have replaceable brushes?
 
That silver box-shaped thing might be a thermal sensor/safety switch.

You need to make good contact when measuring resistance. Clean the plug spades and measuring probes well. Digital meters tend to "jump" because they have to latch the readings in intervals, it's not a "real time" read-out.

When you plug it into the mains, do you feel the shaft vibrate? Like a small but rapid back and forth motion.
 
I cleaned the plug and leads off with alcohol.

When I plug it in, it hums. I don't feel an actual back and forth as much as an overall vibration.
 
A quick refresher on the workings of induction (asynchronous) motors:
http://en.wikipedia.org/wiki/Induction_motor#Starting

Here's the significant passage, which may apply here:
"In certain smaller single-phase motors, starting is done by mean of a shaded pole with a copper wire turn around part of the pole..."

It is hard to tell from that picture, but it looks like there is fat copper wire in the hole next to that "silver box-shaped thing." That could be the starter wire and should be checked for continuity.
 
I don't see this separate wire anywhere (but it's pretty hard to see much of anything in there). But regardless, I don't think it would change my resistance so much. If this starting wire was in series and it was broken, the resistance would be infinite. If the wire was parallel and broken, it wouldn't have an effect on the resistance.

Any ideas of how to get the motor out of the housing? From what I can tell, the housing has little notches punched into it, holding the coil assembly in place. But, there's something else holding it in, or else I would be able to rotate the assembly and pull it out.
 
It's hard to tell, but I THINK that black thing is where the power connects to the coils.

I wish I could pull the whole thing out.
 
The starter wire is usually only one fat winding by itself, and is not connected to the power supply. Induction from the main coil creates a current in the starting wire which creates a secondary (lagged) field that rotates the anchor in that direction. That's how it starts. That one winding gets very hot, a lot of induction current passed through. That silver box thingy may have something to do with it all. Modern technology at play, and without a schematic it is ever so hard to guess.

It may be possible to remove the stator (coil), but it may be even more difficult to secure it later. Looks like the front plate is pressed in.

Any update on the coil resistance yet? Do you have an (old) analog meter you could use instead?
 
I only have a digital meter, and the resistance just goes nuts. And, I can't see well enough into it to see exactly what's going on in there.

Maybe I'll take it to a motor repair place tomorrow.

And GO RAVENS by the way.
 
No. It's an induction "Squirrel-Cage" motor. It has no brushes.

Alright, it's probably an issue with one of the windings, or the bearings. Not much to go wrong with an induction motor. I'd check the resistance on the start winding or see if its shorted to the motor frame.
 
Maybe I'll take it to a motor repair place tomorrow.
Yeah, that maybe the best thing, just keep the diagnosis and repair cost vs replacement in mind. I never thought these motors could burn out before the pump mechanism failed. They look very rugged.

Those Chugger pumps look like a decent alternative. I'd go for the stainless head, looks a lot sturdier. I'm always afraid those plastic housings will crack by sideways forces, NPT fittings, and so on.

I have the feeling the starter winding is at fault, hence it won't start spinning. I measured across the plug both ways, and there is no difference in resistance, pointing to no extra electronics (Semi conductors or capacitors) in the coil circuitry. But that starter winding may be more complicated. The silver box thingy. Did you Google for a schematic or troubleshooting on those kind of motors. They are so simple, really. Is there still some warranty on it?

There is an interesting thread on testing applications of cheap ($22-$38) 12V DC solar pumps:
https://www.homebrewtalk.com/f11/cheap-compact-wort-pump-375904-new/

And GO RAVENS by the way.
:mug: Not much into sports in general, but that was one weird and exciting game. First I so badly wanted the Niners to catch up to make it more interesting ;), then when they did, we were really sweating.
 
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