Still have the electrical short issue

[woodlandfarms]

Every cloud has a silver lining. In all the troubles I was trying to figure out how to unload the 1850 and go buy a brand new one. Getting it by the wife. It was an entertaining few weeks.

 

[SpringHollow]

That problem is easy - ship it to me!!! I would love to get one and modify the **** out of it.

Ken

 

[woodlandfarms]

Well, just put the meter on it (Cold) and I am at 7.2 ohms. Will try and mow today and see what the reading is.

 

[J_J]

How can you have an electrical short and not know it?

It is either shorted with voltage applied, and in that case, something would burn/heat up.

A short with no voltage will show continuity or a beep if you are using a beeper, or a light if using a battery and probe.

An OHM meter should find a short or open if you know which wire and what the condition should be.

I use a tracker that attaches to a wire and I can move the sensor along the wire and trace it.

 

[Marks481]

How can you have an electrical short and not know it?

I had an issue with a corroded wire going from my ignition switch to my starter in my car. Worked fine when the engine was cold, but when the engine heated up, the wire resistance would go up, and than the starter wouldn't turn. Difficult to diagnose because it was an intermittent fault, and usually only showed up when at the end of a long drive, when I was a long way from home, and it wasn't convenient to troubleshoot.

Sounds like woodland farms has an intermittent fault shorting out his draft control solenoid. So it isn't shorted all the time, making it hard to find.

Woodland: I would recommend you just bite the bullet, and just run a new wire from your draft control solenoid from the control switch. I bet the fault is occurring somewhere in the tunnel, and you won't find it until you pull out the old wire and find the insulation scraped off. I assume the draft control switch is wired to be powered off your ignition switch, so it doesn't have a wire going directly from the battery through the tunnel to the switch.

Yeah, it is a pain fishing through the tunnel but dollars-to-donuts says that is where the problem is.

Since your solenoid is reading good (at 7.2 ohms), that is likely not the problem area (still could be a temperature effect thing going on, but unlikely).

 

[SpringHollow]

Short is relative - it can be a high resistance short that pulls enough amps so that things do not work but not so much that it blows a breaker or burns up wire.

Ken

 

[J_J]

Intermittant is one thing and only works sometimes, but a short is a short. A short is an unwanted situation. Continuity is a good thing unless it is unwanted situation.

Either you have continuity or you don't.

Even if you have a high resistance, you still have continuity, and things might heat up. If that short or high resistance is in the tunnel with some hyd fluid, it just might start a fire. Do you have a fire extinguisher handy?

Woodlandfarms has mentioned several things. If you are talking about solenoids, some are rated for continuous operation and others intermittent operation. External heat can also add to the temp of the energized coil.

Are they on the same fuse?

 

[ponytug]

Dear Bob,

You are the electrical engineer in the room; I have to admit I was thinking of the breaker pop as a function of an in-rush current. I agree with you about inductance lowering the current. So, I don't know what to say other than to say observationally poor grounds have popped fuses and breakers for me. I'm trying to think if any of my problem circuits had active loads on them (e.g. an alternator) that could have pushed the voltage/current profiles. It isn't coming to me at the moment.

All the best,

Peter

Peter thanks for addressing my comment. I have seen what you are talking about with AC solenoid a, but don't see how it applies to DC solenoids. Unless the DC solenoid has a resistor that kicks in after the solenoid is engage, I can't see how this happens. DC solenoids putt lower current initially due to the inductance and the current then rises.

Anyway, the shorting after getting hot seems like a likely and reasonable failure and I am very glad the problem has been found. Intermittent problems are the worst problems and will drive you crazy.

 

[woodlandfarms]

So just to review my situation

It seems that the break only happens when the engine is hot, and when I am mowing. I have not had a break when just doing road grading (which does not activate PTO or Draft).

When Draft is off, I did not pop a breaker (One 3 hour mowing session).

Have not run with Draft on and PTO off yet.

I don't think it is a wire issue. I have checked for grounding in the wire. (Ohm Meter Red wire on positive side of wire from switch, ohm meter black lead on ground)

The coil, cold reads 7.2 ohms as per a note here that is what its load should be.

I did remove the coil, it had lots of rust between the actuator and itself. I also cleaned all the connectons, with the positive feed side connector corroded.

As the parts are a few days away, I will continue to test.

 

[J_J]

12v and 7.2 ohms = 1.666 amps, so what size is the fuse.

Watts - volts - amps - ohms conversion calculator

Measure the coil hot of put a heat gun on it and see what happens. Then spray it down with freon and see what happens.

If you have wires in the tunnel, you have no idea of the condition of the wire. Especially if someone has dragged hoses through the tunnel.

An intermittent/momentary short will blow a fuse.