Weird electrical puzzler - breaker pops, the PT1850 runs better until it's shut off

[MikeOConnor]

So next time I tell you not to open the box and to not replace the alternator- what ya gonna do?:confused3:

LOL. Swap the alternator with the new one??

 

[Coyote machine]

Yep, sounds about right:shocked: Hey, it's your money, who am I to get in the way of you spending it?:laughing:
Let me send you my mailing address and a big box to ship some my way....

 

[Soundguy]

Wow! All those posts rolled in while I was typing that last one.

Yes -- the alternator and all the housings were *VERY* dirty. I've been cleaning it wrong for all these years, not realizing that I need to blow out the alternator in addition to the cooling fins. I had to take the housings outside so that I didn't choke to death when I blew them out.

I think I may have replaced an operational alternator, but that's OK. Now I've got a backup.

The weird voltage drop and popping breaker disappeared a few days ago -- so now we have the dreaded "intermittent failure" puzzler. I think I'll just whale on it for a while and see what happens.

Here's a demonstration of how much I love using this machine -- I just bought another one as a backup. Should be here in a week or so.

Actually my guess is that your old alternator is now rated at 2/3's of it's original output. So now you have 'somewhat' of a backup.

 

[Soundguy]

I hate to tell you this.. but that alt aint as different as you think.

the 'idiot' lamp scheme is an old tried and true design, even if implemented slightly differently.

The gm delco(tron) 10SI and 12SI used it. Even the new CS130's use a variation of it ( 15-45 ohm load )

As Mike mentioned, these alternators contain significant quantities of unicorn hair and diamonds.

Deutz is superb at making reliable, compact engines. The flip side to that is that this isn't a New Holland with an extra six inches of room to hang stuff. Also being air cooled, these Deutz engines have rather high air flow over the alternator as it is the primary air source for cooling the engine, and adding extra hardware is likely to cause some part of the engine to get hot because the cooling air is now being deflected. I've done my share of Bubba fixes, but these engines aren't the easiest engines to bubble gum and duct tape things, though I recall another Power-trac owner putting on an external alternator and hanging out the side of the tractor. Sometimes necessity is the mother of invention.

It is hard to find people to rebuild these alternators, but worth it because they are very high quality- look for Iskra/Letrika brand parts, if you can't find Deutz. The diode pack is about $60 on Amazon at the moment. There is a nice troubleshooting article about a similar design alternator here, just bear in mind it is for a car, not this tractor. These alternators function very differently from most US alternators and are therefore wired significantly different from the typical US engine. That makes troubleshooting them a bit different. They are wired to get their starting magnetism through a current draw on a defined source, usually the "Charge" light on the dash. This simplifies the design, and improves the reliability in harsh environments, but it does mean that they behave a little differently. That's why I suggested double checking the battery and ground cables- if they float, it can trash these alternators in nothing flat. If you haven't worked on one of these before, you are likely to find yourself in the swamp in short order. Trust me, I've been there.

For details see the above article. If it were me, I'd replace the brushes and bearings at the same time that I replaced the diode pack.

All the best,

Peter

 

[MikeOConnor]

I have a sneaking suspicion that I actually have two working alternators. One really clean, one really badly in need of cleaning. I hadn't connected all the dots, but I'm starting to suspect that what changed from Weird Behavior Version 1 (voltage drop, popped breaker leading to higher but not full voltage) and Weird Behavior Version 2 (really-high charging voltage, no breaker popping) is when I blew a little bit of the grime out of the alternator with the air hose. It was *really* dirty (because I've gone 13 years without ever blowing it out).

Note to self (and others who run this motor): when cleaning out the cooling fins, also do the alternator and the housings around it. I'll clean the old one up some more when I get a moment. If I find myself with unlimited time on my hands I might try swapping the old one back in once it's cleaned and see if it settles down even more.

But I'm also not through testing the "failed open" hypothesis. I've got a few days of non-tractor distractions in front of me, but then I'll button the tractor back up and go do a short mowing project to stress test it.

I love the PT, but I'm getting to the point where I rely on it too much to have it down for this long (especially with winter snow plowing season coming up). Back in the day, I used to think nothing of buying hot spares for critical pieces of our infrastructure. The second PT is the same thing, a spare that can carry me through the repair times. Two PTs is still cheaper than the skid steer I looked at back when I was weighing alternatives.

 

[Coyote machine]

I agree. When I first saw the pic of alt 1 I thought, WOW! Now there's most of the problem right there. In fact, if you don't end up swapping back to alt 1 I'd cover the new alt and do a through degreasing of the entire engine to allow it to run as cool as it can all the time.
I will bet alt 1 is 80-90% as good as the new one, once thoroughly cleaned, and inspected for burnt anything, including diodes or some other parts. Depending on how many hours on it, may make a difference, especially since it's been running in a dirt bath for 13 years. That does NOT bode well for the bearings and parts that touch internally when she spins. If it were me I'd keep the new one on and save your extra time for something else. Otherwise you risk having to replace alt1 with alt2 all over again.:thumbsdown:

 

[ponytug]

So, what exactly are you proposing as an SOP for cleaning the alternator?

Every time I clean the oil cooler, I use an extended nozzle air jet to clean any dust that can be blown out. I do this from the back (diode side) and the front. Do you have any insights on a better cleaning method?

All the best,

Peter

 

[woodlandfarms]

My same methodology. I put hinges on the engine cover (the cover that covers the jets and exposes the back of the alternator) so I can open the cover more easily. Blow out the radiator in reverse and make sure I hit both sides of the alternator.

 

[MikeOConnor]

Yep, that's what I was thinking I'd do too (now that I realize what's going on).

This takes me back to an ancient thread (that I'm too lazy to look up) where we discussed our homebrew air filters. I called Deutz about a filter for that air passage (which they have btw, but it's wildly expensive and doesn't fit in our enclosure). During that conversation I found out that this engine is not intended for agricultural use. It's a generator engine, intended to be mounted indoors. The tech/engineer I talked to was a little stunned when he heard that I was driving it in dusty fields and sometimes letting it get rained on.

 

[SpringHollow]

These engines are marketed quite heavily for use out in farm fields to run irrigation pumps. It would not surprise me to find that is their single biggest use. And that use is a totally exposed engine out in a dusty field and they rarely if ever get cleaned. So I find it hard to believe they expect them to only be used indoors. I suspect he was not very knowledgeable on how these engines are used or many are used "off label".

Ken