Never had this happen

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ksanders
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Never had this happen

Post by ksanders »

I decided to change it up and pull the old 73 out to cut grass today so I welded the deck and did a bunch of reworking on it and got it hooked up. About 30 minutes in I start hearing a whine that had to be generator. I finished the pass I was on and already started to smell something so got to a spot away from the barn or anything and shut it down. The generator was smoking generously so I grabbed a fire extinguisher and wrenches and heat resistant gloves and took it off quick. The grass I threw it on smoked even. I took it apart expecting bearing and saw a partially melted armature. Never saw this. It was charging when I started today, was turned on and off many times adjusting the deck, and this was professionally rebuilt several years back for around $150 for the works on it. Anyone see this before?
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From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

Klapatta
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Re: Never had this happen

Post by Klapatta »

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Yes sir it happens. The field windings can catch fire too. With their closed cases you will not smell a thing until the external paint starts burning.

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ksanders
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Re: Never had this happen

Post by ksanders »

I got lucky and could smell this from the rear vent hole and got it all off quick enough. Ironically I recently sold my last good one to a kid on the cheap to help him so guess I get to rebuild one quick. Sadly the bearings and field coils still looked pretty new.

Would this be a short in the armature or field coils or no way to know without an ohm meter?
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

Klapatta
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Re: Never had this happen

Post by Klapatta »

An armature short can be one likely cause yes. The insulation is obviously compromised. Armatures can be problematic to test on the bench. Yours is stamped with OEM style markings so it has been around for a very long time. For testing purposes I prefer a 120 volt test lamp with a 25 watt bulb over an ohm meter. The more pressure pushed in the during the test the better the chance of finding a short. Be careful if you do this. While they may test Ok on the bench keep in mind that they rotate at around the 10,000 RPM band. I had one that drove me bonkers. It would start the engine perfectly then once the engine started coming up to speed power generation would cease. It would charge for only a second or two at the most and then cut out. Thought that I was dealing with a wire harness or voltage regulator issue since it started so well. As it turned out there was an open in the armature that showed up only at higher speed and reconnected itself after shut down. I discovered this only after taking a chance by doing an armature swap with a known charging unit. Replacement armature, problem gone.

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ksanders
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Re: Never had this happen

Post by ksanders »

Thanks for the help! Generators are one thing I never messed with too much besides basic rebuilds because we used to have an old man that rebuilt them dirt cheap when I was big into these.
Now only my 73 and 102 even have one anymore. Once you mentioned that I cleaned up my existing generator real good and the field coils looked okay (though they got plenty hot). Before going any further I had another generator that turned but fields were known bad on it. I took that armature, cleaned it on the lathe, and used the existing case and end cap. Tractor fired right up but ammeter jumped higher than I'm used to and never came back. Battery tester said it was charging over 16V and around 14v at low idle. Messed with regulator and didn't get ironed out so I stole the one from the 102 that's known good. Ammeter was more in the usual range and battery tester never got over 14v so I'm going to get a regulator and a couple new starter bearings since the ones on that armature are plenty loud, and repaint it. Still way better than I thought I'd come out. I was ready to buy every part before one of the whole China eBay units for this particular application.

Thanks again!
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

JMotuzick
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Re: Never had this happen

Post by JMotuzick »

I had a similar issue years ago, I put a used starter on my 70. Someone before me stole the starter, that had a hand wind rope pulley from another brand on the flywheel, you had to turn the engine over backwards to wind it! It started easily with 1 or 2 try’s. After installing a starter generator, It started and ran fine but the starter got hot and cooked. Same deal with a bad regulator, it was over charging. It cost me a rebuild on that starter and a new regulator, a weeks pay just out of High school!

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ksanders
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Re: Never had this happen

Post by ksanders »

I think when this was rebuilt I was in middle school and it cost $142 which was a lot of what I had period.

Just to follow up I installed two new bearings and new regulator. It charged right and seemed fine but after 20 minutes of light lawn sweeping burned again. This time I caught it sooner but looks like the armature was physically rubbing one of the two field coil metal hold downs. It wasn't loose, bearings new on armature so it wasn't flopping, and it charged right up to when I shut it down. All I can figure is something expanding when warming up. It's only one side, not both but I know what the problem was I guess.
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

Klapatta
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Re: Never had this happen

Post by Klapatta »

If $142. was spent back in the day then most likely the field windings were changed out. There does need to be some clearance between the winding retainer plates and armature. In this case I think that as things expand a bit an interference issue shows up. Normal operating temp for these units is about 140 degrees, that is the point where one can touch the unit for only a couple of seconds before having to pull ones hand away.With the bearings in good shape and the case ends aligning properly that would rule them out as the culprits. The field winding that is rubbing is most likely miss aligned or not fully compressed. If the winding is installed at somewhat of an angle that can cause an issue, it must be at 90 degrees relative to the case. Also they are manufactured with a radius that is slightly smaller than the inside of the case. This is to create a clamping affect not unlike of what a split lock washer does. Your winding may not be fully compressed. Just tightening the single bolt will not clamp and draw it down all the way. A field pole shoe install tool must be used to obtain full compression. It is installed, tightened, then the retainer bolt is torque in place.
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A couple of Kant Twist clamps can obtain the same result however they must be drawn up evenly.

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ksanders
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Re: Never had this happen

Post by ksanders »

Thanks for all the information. I'm confident it's the field coil. It's probably swelling a bit like you said when hot. I took it off and looked and could move it to where it ran and never smoked but did stop charging after 30 minutes. I'm just going to find an electric shop and have it rebuilt. I've called around and that seems surprisingly difficult. Both places I used to use are apparently gone. I'm not in a rush but if I don't find a place will buy the coils and just do it and if it goes well do a couple of the old generators I have sitting here.
Again, thanks for all the help!
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

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