There is a local opportunity to buy a used, name brand tow behind generator that is not working as follows: the engine (4 cyl. White diesel) is running fine, the generator is not making any output.
I think that it will be a good way to spend some time in the fall messing with it. As with most dead electrical things, the hope is that there may be something simple with it.
My question is whether the above assessment is realistic. Has anyone tried fixing generators that would not make output?
i
if you haven't bought it yet, use the smell test. Stick your nose up near the armature. If it smells like majic smoke escaped, beware. otherwise, good chance it doesn't need a rewind and repair might not be bad.
Karl
Thanks... It is a little too far from me to just go and smell. I will try my luck with a low price. By the way, the drive I mentioned yesterday works fine.
iI had a bad armature and regulator on mine. $200 fix for a handful of parts. An afternoon. Replacement genheads are also available from harbor freight and other places.
I had a bad armature and regulator on mine. $200 fix for a handful of parts. An afternoon. Replacement genheads are also available from harbor freight and other places.
Ignoramus19946 fired this volley in news:fKmdnZjR4Ijjfk_bnZ2dnUVZ snipped-for-privacy@giganews.com:
Yup. I acquired an old Dayton 3.5KW genset (real 3.5... it'll start a 5K load). Very old iron. Updraft 8HP cast iron Briggs. Built in 1962.
Once the engine was running well, the output was zilch-point-nothin'. The thing had been sitting unused for 25 years, so we assumed the residual magnetism in the field pieces had drained, "rang" the field, and it started putting out.
It stopped working again about two years later, and I found that the slip ring brushes were frozen in their guides. Cleaned everything up, replaced the brushes with some larger ones filed down to fit, and it's been playing ever since (20 more years).
I later added some 8" casters to the base, hung a starting battery under the carriage, added some controls (key-start, charge/no-charge switch, taps for meters, etc.), and switched from magneto to automotive-style coil.
The starter is a "starterator" type setup. The starting coil becomes the battery charging coil during operation.
The old beast will even run at reduced output on kerosene if you start it on gas. (although at today's local price for #1 white kerosene, it would be dumb.... probably lots cheaper in 1962).
LLoyd
Very nice Lloyd. Most likely I will not win it, but if I do, it should be a fun thing to mess with. I had very good luck with everything diesel powered, so far.
iIgnoramus19946 fired this volley in news:fKmdnZjR4Ijjfk_bnZ2dnUVZ snipped-for-privacy@giganews.com:
I was gifted a nice but non-functional JD estate tractor. 32HP diesel with all hydrostatic stuff.
The engine runs fine, although I think it's going to need an injector pump rebuild... stumbles a bit at high speed.
BUT... although every hydraulic accessory on it works perfectly - lift, blade PTO, accessory PTO, everything - the traction drive will turn the wheels under no load, but won't move the tractor. You get a little minor "oommph!" out of it when you attempt to drive, but it won't move in either forward or reverse.
I noticed that someone had butchered the (very expensive) "neutral" valves because they were leaking. Thinking this was the problem, I removed both, replaced o-rings, etc, and _think_ I've made sure the valves are in the "closed" position (basically welded shut).
Anyone seen this problem? It seems like the pressure is being bypassed around the traction motor somehow... and the neutral valves still seem to me like they'd be at the heart of it.
LLoyd
Well I got away with it whwn I bought one a couple of years back. Engine fine, no o/p from the generator (this was a 100kva 150 HP 6 pot in line Ford twin axle trailer job). I proved to myself that the regulator was u/s as there was no drive to the field. Sent it back for re-work, to find some twit had tweaked to o/p voltage down to zero - the regulator was actually working fine and keeping that zero voltage constant !!!
AWEM
"Lloyd E. Sponenburgh" fired this volley in news:Xns9999712381160lloydspmindspringcom@216.168.3.70:
BTW... the tractor cannot be moved by hand with the neutral valves installed, further making me think they're "closed" correctly.
LLoyd
My backhoe used to seize up after I used it for a while; there was an overpressure / bypass valve on the pressure side of the pump (well, in that circuit, was a ways away). When it'd trip, all the flow would bypass anything useful and just shunt back to the low pressure side. Sounds like this is what you're seeing?
Do you have a schematic that shows, at least in general, where the various valves are? It sure does sound like an overpressure bypass that's stuck in bypass mode. Broken spring or somehing; any pressure in that circuit, it thinks is overpressure?
Dave
Dave Hinz fired this volley in news: snipped-for-privacy@mid.individual.net:
The parts drawings are available on-line... got them. But the service manual which shows the schematic is over $100. I'm stuck with the "brute force" method of trouble shooting, unless someone can feed me copies of the salient docs.
LLoyd
Have you given your local servicing dealer a buzz? Sometimes they're nice and will copy a diagram for you. Of course, given the value of the machine in question I don't think a $100 investment in the full service manual is unreasonable. Whenever I order a new vehicle I also order the factory service manual set. $100 or so for the manuals is a negligible cost to be able to properly service a $30k vehicle.
"Lloyd E. Sponenburgh" fired this volley in news:Xns999972ED79A12lloydspmindspringcom@216.168.3.70:
I should also add that this is not a "rationally designed" hydraulic system. EVERYTHING is contained in the transaxle housing. Durn!
LLoyd
My experience is with smaller (5000 watt) gasoline generators but I've had low or not output on two of them because of shorted or open diodes. I also had one that just needed needed to be re-magnetized (see How To Flash An AC Generator--8/12/07 this NG). I'm no expert but so far if it had bad diodes when I tested the resistance of the coils on the rotor and stator they were both about equal with an open diode and zero ohms with a shorted doide. The diodes need to be disconnected for an accurate reading. Zero ohms on a coil could also be a shorted coil. I had that happen once and it was pretty obvious from the molten copper.
Hey Iggy, Before you go to hauling that thing all the way home, you should at least do a Megger Test on the Sator and Field Windings, to make sure they aren't shorted to ground, and are not burnt open.
If that proves OK, then it would be worth the fuel for the haul Home, because if they need to be ReWound, the costs will be significant, for a Winter Project type adventure.
Bruce in alaska
Lloyd, you should post this question over on the SmokeStak.com board in the "Traction" and, or "Tractor" Forums.... I suspect you will find someone, who has either rebuilt or repaired a similar problem.
Bruce in alaska
Very Very common problem unfortunately. The newer John Deere hydrostats are bad this way. They don't have a oil filter and people don't change the oil often enough to prevent this.
First off a lesson in hydrostatic drives.
First step is that the oil from the axle is picked up and pumped to about 500 psi by the lift pump (a gearotor type pump on the older units). This pump provides the power for the accessories and provides oil to the main hydrostatic drive pump. (thus the reason you've got power).
Next step the oil is pumped by a variable displacement pump. This is likely where your problem is. The variable displacement pump looks kind of like a the cylinder in a revolver. The cylinder revolves against a valve plate on the front end. It has pistons that are lapped to fit it that free float in the cylinder (the reason for the charge pump is to push the pistons back). The back end of the pistons have feet kind of like what's on the end of the screw of a C-clamp. These feet ride on a "swash plate". The swash plate is controlled by the "gear shift" so the when you're in neutral it's flat and the pistons don't move. When you want to go forward you tilt the swash plate one way and for reverse you tilt it the other way.
The usual failure mode of these pumps is that the face of the cylinder and the valve plate get grooves cut in them from dirt in the fluid. Once this happens the oil leaks past and the pump can't build up any pressure.
From everything that I've heard there are no replacement parts available for the newer John Deere pumps. I was able to get a new valve plate and I lapped the face of the cylinder on my old (pre 1970) John Deere hydrostatic mower. But that was about 18 years ago when I did it. Since this is a metalworking group it's likely that you've got the skills and equipment to repair the valve plate and cylinder (I didn't have any machines except a drill press back when I repaired my old mower).
From what you're saying I think that you're hydraulic motor is still in good shape (common).
JD builds hydraulic systems without filters???!!! My opinion of JD just fell precipitously :(
A friend of mine had the same problem on his. It was somthing simple in the linkage or on the transmission itself. His was an older JD 350.
John
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