Still have the electrical short issue

[marrt]

Why not install a (slightly smaller) fuse in front of each of the suspects. Fuse holders and fuses are cheap, compared to your time. Then, you'll see which one keeps blowing and go from there. Reconnect everything as you wish after the problem is solved.

 

[BobRip]

Why not install a (slightly smaller) fuse in front of each of the suspects. Fuse holders and fuses are cheap, compared to your time. Then, you'll see which one keeps blowing and go from there. Reconnect everything as you wish after the problem is solved.

A fuse sized for the actual load would be better. If you have three loads and all are on a short could still blow the common fuse. So make each fuse just a little larger than the actual load it powers. This is a good idea in general, just needs a little tweak. I think he has found the problem.

 

[woodlandfarms]

All interesting ideas but what is breaking is the Main circuit breaker, that turkey style popout (I would call it an aircraft breaker) that you can reset. I think they work / at different than a fuse but what do I know.

 

[marrt]

Correct, but something is creating a very abnormal load to cause this circuit breaker to pop. From what I know about Power Tracs, this breaker seems to be "the last line of defense" against catastrophic failure. Consequently, the actual culprit should easily pop a properly sized inline fuse before the breaker goes (assuming the breaker is not defective).

 

[BobRip]

All interesting ideas but what is breaking is the Main circuit breaker, that turkey style popout (I would call it an aircraft breaker) that you can reset. I think they work / at different than a fuse but what do I know.

By adding the other fuses (one for each device) you can isolate to that device.

 

[woodlandfarms]

Well, here is tonights results and I think we have the solution in hand.

I went and mowed for a while, with all switches on. Fuse pops at normal time. I then turn off the Draft Control, and continue mowing - no issue for half hour. I then turn it back on and pop. OK, so it is the draft but what part.

So I then disconnect the coil (the wire is around 5" long from the coil) and turn the switch back on, thus charging the wire on the circuit. No pops. So, I am feeling pretty sure at this point it is the Coil and only the coil.

New one en route.

 

[bumperm]

Sounds reasonable to me. The failure could be an internal intermittent short that is heat related, i.e. insulation breaking down or thermal expansion causing the short to occur within the solenoid's can.

This part should not cost >$200, and as others have said, should be easy to find a suitable replacement for less than $20. Continuous duty, 12 volt coil, and a higher amp rating on the contacts than the load required. This type of contactor or solenoid is in common use in golf carts etc. Napa Auto parts, McMaster-Carr on-line, or Amazon: Amazon.com: Cole Hersee (24059-BP) 12V Insulated SPST Continuous Duty Solenoid: Automotive

that's a 65 amp 4 terminal one, which means the coil has independent terminals. They come in a 3 terminal variety too, with one end of the coil being internally connected to either the input or output contact terminals (to make the 4 terminal version work as a 3 terminal, just add an external jumper from one of the coil terminals to a contact terminal.

It's common to add a diode across the coil terminals (reverse biased, banded end or cathode on the positive coil terminal), this "flyback" diode will suppress the "inductive kick" or reverse EMF when the voltage to the coil is switched off. Otherwise the high voltage spike, typically several thousand volts but low current, generated by the collapsing magnetic lines of flux can damage other components over time. A 1N4001 or similar works fine for this - Radio Trash "you have questions, we have blank stares" should have 'em.

Good idea to slather a little silicone grease, Dow DC-4 or similar, on electrical connections that are exposed to the elements, it'll prevent prevent corrosion and resistance build up in connections, keeping the gas tight. Cheap insurance.

bumper

 

[woodlandfarms]

WOW. now that is a bucket full of information bumperm. Thank you. I found the original sourced for around $40 with shipping (Part = $15, shipping = $25) if indeed I am overcharged by the factory.

Will look into this diode conversation. PT is sort of a simple brick in terms of construction. A few guages and switches. No fancy electonics for these guys. But your diode idea cannot hurt.

 

[cqaigy2]

I wonder if you could use a small ceramic capacitor across the coil, pretty cheap, tough and not too worried about high reverse voltages and i have some of those too. I never thought about being worried the EMF from the solenoid coils, good to know.

 

[ponytug]

Carl-

Amongst the many options for this solenoid are ones with an internal diode.

While it never hurts to have protective diodes, nothing on this machine is transistorized, so I'm not sure there is a huge upside. (Marginal improvement in switch lifetime due to a reduction in arc at the contacts?)

Great post by bumperm- I second the dielectric grease suggestion, especially on a power trac, where it seems there are lots of connections somewhat exposed to the elements. I use a copper containing version on the engine interconnect harness- it improves electrical conductivity while shielding the actual contacts from the elements.

Your post makes me want to be extra careful anytime I'm washing the tractor. I think I might do a pre-emptive disassembly of the coil and contacts. While we are currently in a drought, it will get washed again sometime. :laughing:

All the best,

Peter

WOW. now that is a bucket full of information bumperm. Thank you. I found the original sourced for around $40 with shipping (Part = $15, shipping = $25) if indeed I am overcharged by the factory.

Will look into this diode conversation. PT is sort of a simple brick in terms of construction. A few guages and switches. No fancy electonics for these guys. But your diode idea cannot hurt.

 

[Marks481]

This type of contactor or solenoid is in common use in golf carts etc. Napa Auto parts, McMaster-Carr on-line, or Amazon: Amazon.com: Cole Hersee (24059-BP) 12V Insulated SPST Continuous Duty Solenoid: Automotive

Bumper-
This is not a contactor. It is a solenoid-operated hydraulic valve. We are discussing replacing the coil, which can be easily replaced on the hydraulic valve;

The coil looks like this:


And goes on a solenoid valve...which IIRC looks considerably different than this:


That being said, the flyback diode might not be a bad idea, but probably isn't related to the fault that Woodland is troubleshooting.

 

[BobRip]

Put in the diode. It will protect the contacts, but in addition it will protect the coil. The high voltage generated without the diode can cause arcing in the coils which can breakdown the insulation and damage the coil. This can potentially damage the insulation on the internal wires. The coil might short or have an intermittent short, just like you had. A capacitor may work, but can cause resonance and some high voltages if chosen wrong, but it is better than nothing.