Stick in the Fan

Charlie_Iliff · Jul 16, 2008

Periodically, I set a trap for myself, usually by a "temporary" solution to a problem, left for later fix. The one I fell into this time involves a 10 amp fuse that blew when I got a stick in the hydraulic fan a few years back. Since I didn't have a spare 10 amp handy, I stuck in my spare 50 amp. It was still in there yesterday when a stick took off a couple of fan blades and jammed the fan. So,with the motor cheerfully emulating a short circuit, and 50 amps to play with, the motor is toast, and the wires to it uninsulated. Worse, the whole system is now a bit erratic, with the voltage occasionally dropping to 0 and the engine quitting, and the panel 20 amp breaker popping frequently.
So, Terry's sending a fan and a breaker, and I'll spend some time with the schematics and a meter.
I think I'll also get a new 10 amp fuse for that fan circuit.

KentT · Jul 16, 2008

I've also had to replace my fan because of REPEATEDLY getting sticks caught in it... my PT is used in the woods more than anywhere else.

At least it's an easy thing to replace, though I could've saved a few $$ by shopping around and trying to find the equivalent fan on the after-market. Here's hoping your wiring harness isn't damaged...

cqaigy2 · Jul 16, 2008

I bet you could find a fan at auto wrecking for pretty cheap.

Sedgewood · Jul 17, 2008

Charlie_Iliff said:
So, Terry's sending a fan and a breaker, and I'll spend some time with the schematics and a meter.

Oh - oh, Charlie, wish I had said something sooner.... My fan died a while back and I went off to Advance Auto Parts and bought an Imperial #226116 reversible 16 inch fan to replace that cheapo 14 inch PT had on there. Other than Terry's replacement, whatever you get needs to be convertible to a "sucker" from the more typical "pusher" type. It took a little cobbling to get it mounted (but only a little) and it "fans" much better - so much so it even lowers the engine oil temp about 10 degrees and we all know what an issue that is

. If you change your mind and go this route you'll need a 20 amp fuse!

Sure glad to hear that dreaded four letter F...! word didn't end up in your story. Good luck with the rewiring.

Sedgewood

Charlie_Iliff · Jul 18, 2008

Thanks Sedgewood, but I've managed actually to schedule a vacation trip the end of next week, so I don't have any time to play with a modification. I haven't had insurmountable problems with the stck setup when working properly.
I, too, am glad that no dreaded F--- words have been involved .... yet.

Charlie_Iliff · Jul 20, 2008

Charlie_Iliff said:
So, Terry's sending a fan and a breaker, and I'll spend some time with the schematics and a meter.
I think I'll also get a new 10 amp fuse for that fan circuit.

I called Terry Wednesday. The fan and breaker came Friday. The schematic and meter time so far has been about 10 hours, and the temperature has been about 105 in the shade, I think.

It appears my regulator is fried. I don't know if directly caused by the fried fan motor, or by that combined with a bad ground. The ground from the harness to the engine was to a #8 bolt in the bottom of the junction box on the right side of the engine. The box itself had broken its mounts, so there was no ground at all. In fact, the ground side of another circuit was hooked to it, so it probably had at least intermittent positive voltage. I don't know if that ground actually goes to the regulator, but I do know that when the 12V "accessory" wire is attached properly to one end of one of the diode packs, the engine runs for a few seconds and blows the panel circuit breaker. If I disconnect the "accessory" wire from the front electrical junction block, the back one, or the alternator, the engine runs, but there isn't any charging.
Sounds a bit like Altavista lawn's problem a while back. A couple of posts have talked about an external regulator, but I don't see one. Sedgewood, have you had those bits apart?
When I can track down some torx sockets, I'll take the alternator off and get it to a test bench, unless someone has some better advice.

ponytug · Jul 20, 2008

Dear Charlie,

Alternators have this funny need of having a defined + & -, or they happily invert, and when they do, it tends to fry the regulator, since most alternators use a half wave rectifer instead of a full bridge.

I would definitely pull it and get it to a test bench to ensure nothing else fried.

I thought that you had installed multiple grounds. Did I miss something?

All the best,

Peter

Sedgewood · Jul 21, 2008

Charlie_Iliff said:
Sounds a bit like Altavista lawn's problem a while back. A couple of posts have talked about an external regulator, but I don't see one. Sedgewood, have you had those bits apart?

I'm beginning to see the value in sizing fuses properly :-(( No, I have not had any alternator bits apart - that's one system that hasn't failed me yet knock on wood. Whatever I did for grounds in rewiring after the fire seems to be working but I can't remember right now what I did. At least that ridiculous junction box is long gone.

Back at the time of the fire in my 1845 I made my own drawing of the wiring logic from Power-Trac's hard to read schematics and I see that the hydraulic fan and Alternator '+' terminal share a conductor in the cable through the tunnel. Did your cable survive the short? I wonder if you might have a short in the tunnel cable. I don't envy you having to replace it.

A link to my PT-1845 Wiring Diagrams

Sedgewood

ponytug · Jul 21, 2008

Dear Sedgewood,

I'd have to check myself, but I think that the (+)12v line that is shown shared in your original wiring diagram is used to set the polarity of the fields on the alternator.

It is critical that this terminal (The D+) have 12V on it at all times, or the alternator could switch polarity, which has disastrous consequences for the regulator and diodes.

I have retightened my terminals a few times, whenever I have been in the region. The stacking terminal blocks that the PT used on mine are easy to assemble, but temperature cycling seems to loosen them. I've considered soldering all the wires to improve the connection, but I haven't done it.

I got a little water in the ignition switch and promptly had troubles starting the PT. (Fixed by blowing it out, and applying anti-oxidant contact cleaner, and blowing it out again.)

Anyone have suggestions/recommendations on a more water resistant replacement? Sedgewick, do you know the ampere rating on the PT switch?

Any thoughts on this one?

All the best,

Peter

Sedgewood said:
I'm beginning to see the value in sizing fuses properly :-(( No, I have not had any alternator bits apart - that's one system that hasn't failed me yet knock on wood. Whatever I did for grounds in rewiring after the fire seems to be working but I can't remember right now what I did. At least that ridiculous junction box is long gone.

Back at the time of the fire in my 1845 I made my own drawing of the wiring logic from Power-Trac's hard to read schematics and I see that the hydraulic fan and Alternator '+' terminal share a conductor in the cable through the tunnel. Did your cable survive the short? I wonder if you might have a short in the tunnel cable. I don't envy you having to replace it.

A link to my PT-1845 Wiring Diagrams

Sedgewood

J_J · Jul 21, 2008

I have eliminated the ignition switch on my 1445 after some of the same problems some of you are having. I have an on/off switch for the main switch, and a momentary switch for the start switch. Your switching situation may be different , but you could so something similar, plus add an accessory switch if needed. These switches could be mounted under the dash, or mounted in a switch panel under the ROPS.