Lucky to be ALIVE!!!

[ecbaatz]

The starter motor is grounded to the block, and the block through the frame, and the frame through the tires to actual earth ground.

Coyote Machine, I agree with the above statement until you state that it is grounded thru the tires to the ground. The tires are rubber, rubber is an insulator.

At least that is what I was taught in my 20 years in the Navy as an electrician on submarines.

 

[aczlan]

You call it shorting across the solenoid, I call it a short to ground. We're both right because without the ground one has not completed a circuit.

Not by the terminology that is commonly used or by what happens. Until this thread, I had never heard of shorting across a solenoid referred to as shorting to ground.
By your logic, I should call hooking up a motor the same as connecting the wires directly to each other. There is a difference, there is resistance in the motor windings, so it isn't a dead short like shorting to ground would be.

Here is an article describing what a short to ground is: Automotive Technology Studies - Short to Ground - Session 10 - 1
They say in part: A short to ground occurs when current flow reaches ground before it is intended
Note the bolded part. That is what makes it a short to ground, that the current is reaching the ground before it was intended to.

Aaron Z

 

[RaydaKub]

The starter motor is grounded to the block, and the block through the frame, and the frame through the tires to actual earth ground.

Coyote Machine, I agree with the above statement until you state that it is grounded thru the tires to the ground. The tires are rubber, rubber is an insulator.

At least that is what I was taught in my 20 years in the Navy as an electrician on submarines.

Exactly. If you put a cable directly from the negative terminal to a ground rod driven into the ground it still won't start. It has to be a complete circuit back to the source of the energy, which is the battery. That's why they call it a "circuit" as in the electrons travel in a circle.

The reason an AC line is dangerous after a storm is because the generator is really grounded, even though it may be hundreds of miles away. The electrons want to return home. Earth ground has no relevance when it comes to a tractor's starter.

 

[TomSeller]

I think the reason the tractor did not start was the fuel cut off knob was still in stop position from the last time Gary stopped the tractor. I do not recall Gary saying he ever moved the fuel cut off back to run position. Gary, did you?

This is like a mystery novel.

 

[Coyote machine]

The starter motor is grounded to the block, and the block through the frame, and the frame through the tires to actual earth ground.

Coyote Machine, I agree with the above statement until you state that it is grounded thru the tires to the ground. The tires are rubber, rubber is an insulator.

At least that is what I was taught in my 20 years in the Navy as an electrician on submarines.

OK. We could get into a whole other discussion about what constitutes a ground, an insulator, and an isolator, etc. RE: NEC code, UL and CSA, but that isn't pertinent here. Here's an interesting twist on grounding. A state police cruiser rooftop antenna was struck by lightening and the resultant charge blew out one of his rear tires, literally as a result of the strike. The strike found it's ground in the ground, though those who know lightening technically in detail know that little 'tracers' IIRC, are sent up from the earth/ground that meet the lightening strike instead of the commonly thought to be lightening coming from the sky.
Ok, I'll concede that as far as the tractor or auto finding earth ground, it is not necessary to pass directly to the earth, as would be the case in house wiring, but that is not to say that a ground is not ever found on things like an auto through rubber. Remember when cars had rubber straps going to the ground to prevent shocks from going to the toll booth operators and possibly for other reasons, I'm unaware of?
And being a sub guy I'm sure you know of stray voltage issues in salt water and between boats that can cause problems like the submerged outboard engine parts getting 'eaten' by the electrolysis?
Do subs encounter this, or do you have other methods of eliminating the problem?

Not by the terminology that is commonly used or by what happens. Until this thread, I had never heard of shorting across a solenoid referred to as shorting to ground.
By your logic, I should call hooking up a motor the same as connecting the wires directly to each other. There is a difference, there is resistance in the motor windings, so it isn't a dead short like shorting to ground would be.

Here is an article describing what a short to ground is: Automotive Technology Studies - Short to Ground - Session 10 - 1
They say in part: A short to ground occurs when current flow reaches ground before it is intended
Note the bolded part. That is what makes it a short to ground, that the current is reaching the ground before it was intended to.

Aaron Z

So because the wrench shorted the path to ground it was not reached before it was intended to? I suspect Gary would argue different. He didn't 'intend' for the wrench to find a ground at all, but it did, and not through the ignition switch, not through a starter remote switch, but directly through shorting out two posts that allowed a short path to ground at the block via the solenoid/starter circuit. The wrench shortened the path to ground; in other words the wrench was NOT intended to FIND a path, or PROVIDE a path to ground, but it did and the path was shorter than going through the ignition wires, etc, etc.
And just because you haven't heard a particular terminology used doesn't make it invalid. Your example of hooking up a motor or attaching two wires being the same thing is ludicrous. You stick by your terminology, and I'll use mine and we'll just have to disagree. I have no desire to debate this further.

 

[Coyote machine]

I think the reason the tractor did not start was the fuel cut off knob was still in stop position from the last time Gary stopped the tractor. I do not recall Gary saying he ever moved the fuel cut off back to run position. Gary, did you?

This is like a mystery novel.

That could well explain why he did not get a running motor from the starter's circuit trying to make it run.

 

[Garycw]

I think the reason the tractor did not start was the fuel cut off knob was still in stop position from the last time Gary stopped the tractor. I do not recall Gary saying he ever moved the fuel cut off back to run position. Gary, did you?

This is like a mystery novel.

The fuel cut off knob is spring loaded. You pull it out and hold till engine dies. If you release before completely stopped it springs back and engine continues to run. It's Always in run position until you pull it and hold it. When released. It automatically goes back to run.
SS far as the shirting terminology debate, when trying to carefully tighten large soleniod terminal nut, it may have actually shorted to " positive" either way the wrench momentarily completed the circuit , engauged starter, and stayed engauged even though wrench fell clear to the floor if barn. Once in neutral, starter Disengauged, but soleniod did not, until I hit it again. I'll be checking all the connections someday. ( including the clutch switch) and I can assure the battery will be disconnected( both terminals) or removed. I experienced the blown fuse issues after adjusting clutch. The back of that terminal could have something to do with it latching in. If it had not latched in I would have possably had time to have gotten into neutral and rolled back off my foot & ankle before lurching again to the point of no return.

 

[Garycw]

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I think the reason the tractor did not start was the fuel cut off knob was still in stop position from the last time Gary stopped the tractor. I do not recall Gary saying he ever moved the fuel cut off back to run position. Gary, did you?

This is like a mystery novel.

The fuel cut off knob is spring loaded. You pull it out and hold till engine dies. If you release before completely stopped it springs back and engine continues to run. It's Always in run position until you pull it and hold it. When released. It automatically goes back to run. I thinks the gate actually kept it from starting. Like trying to start in gear with front of tractor against a wall. The gate did a good job holding it back, but was loosing gradually.
As far as the shorting terminology debate, when trying to carefully tighten large soleniod terminal nut, it may have actually shorted to " positive" either way the wrench momentarily completed the circuit , engauged starter, and stayed engauged even though wrench fell clear to the floor if barn. Once in neutral, starter Disengauged, but soleniod did not, until I hit it again. I'll be checking all the connections someday. ( including the clutch switch) and I can assure the battery will be disconnected( both terminals) or removed. I experienced the blown fuse issues after adjusting clutch. The back of that terminal could have something to do with it latching in. If it had not latched in I would have possably had time to have gotten into neutral and rolled back off my foot & ankle before lurching again to the point of no return.
Ps.. Please excuse some of my spelling, this is all being done from my trusty life saving phone

 

[aczlan]

So because the wrench shorted the path to ground it was not reached before it was intended to? I suspect Gary would argue different. He didn't 'intend' for the wrench to find a ground at all, but it did, and not through the ignition switch, not through a starter remote switch, but directly through shorting out two posts that allowed a short path to ground at the block via the solenoid/starter circuit. The wrench shortened the path to ground; in other words the wrench was NOT intended to FIND a path, or PROVIDE a path to ground, but it did and the path was shorter than going through the ignition wires, etc, etc.

But the wrench did not provide a path directly from positive to ground, it provided a path from positive to positive and the motor provided the path to ground (after it got some work out of the electrons).

And just because you haven't heard a particular terminology used doesn't make it invalid.

True, but when the terminology is not the standard terminology and it is likely to confuse people, I am very comfortable saying that it is invalid.
Can you provide some examples of "short to ground" being used to describe shorting across the terminals of a starter (or otherwise bypassing an electrical switch)?
Pretty much anytime you find the term short to ground used, it is describing a connection directly from positive to ground (such as a wrench or wire between the + and - terminals on a battery or from + to the frame of a vehicle).

Your example of hooking up a motor or attaching two wires being the same thing is ludicrous.

Why? Lets say that I am working on a well pump (like the one pictured here: http://inspectapedia.com/water/PressureSwitch004DJFs.jpg ). It has what appears to have a flakey pressure switch, so I short across the terminals with a pair of screwdrivers to bypass the switch and turn the pump on (to verify that its the switch and not the pump before I go by a new switch).
Using your terminology, shorting across the terminals is referred to the same way as connecting the hot wire to neutral or ground because the screwdriver "was NOT intended to FIND a path, or PROVIDE a path to ground, but it did and the path was shorter than going through the" normal run down the well and through the pump motor.
Will shorting across the terminals (positive to positive) be likely to trip the breaker if the pressure switch is the only bad component? No.
Will shorting to ground (positive to neutral or ground) be likely to trip the breaker if the pressure switch is the only bad component? Yes.

You stick by your terminology, and I'll use mine and we'll just have to disagree. I have no desire to debate this further.

How do you propose to differentiate between shorting across the positive terminals (bypassing a switch, solenoid, etc) and doing what everyone else refers to as shorting to ground (positive to ground)? There is a significant difference which is why most people only refer to shorting from positive DIRECTLY to ground as shorting to ground.
Next time you see a mechanic or an electrician, ask them if your car/tractor would start if you short to ground at the starter terminal (with no other explication) and see what they interpret it as. I can pretty much guarantee that they will interpret it as shorting positive directly to ground.


Aaron Z

 

[skyhook]

I understand what CM is trying to say,
Current needs a "return" path to ground, but to safely do so, it also needs a ( without getting to technical ) "load" in it's path.
Without this load ( light, starter, radio etc, etc ) it is considered a short to ground,
depending on the amperage, this short to grnd can cause considerable damage.
Again, my take on this is the solenoid "shorted" closed, this is probably why the starter still spined,
when it was put in neutral, when Gary hit the solenoid again, it dislodged the internal short and opened the solenoid.



Good morning Gary,
how ya feeling this morning, whats the weather like down that way.