24 volt to ground? Am I reading this right?

Sharecropper

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While pondering all things CUCV, it occurred to me that the starters in our trucks, which are the only 24 volt appliances under the hood, are indeed grounded because they are bolted to the engine. Does this mean it’s OK if 24 volts are returned to the electrical system through a vehicle ground?
 

richingalveston

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That is why the ground straps to the motor are so important. Without the large ground straps, The voltage to the starter has to run through the small ones and when those fry, It can even run through the coolant.
Electricity will take the path of least resistance and make the shortest path possible back to ground.
DC can run the opposite direction. The correct terms for DC voltage are actually Supply and Return. You can have a negative supply and a positive return. Most telecom systems run using -48Volts not +48volts. ( I spent 10 years building telecom facilities)
The entire truck body and frame are a ground. There is not any harm done
 

Guyfang

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Long ago, in a far, far off land, Germany, 1973, I learned this. We were using a 52300, 45KW generator to power the Basic HAWK missile system. One fine day, we got the NEW, 60 KW, MEP-115A generator, to power the NEW HAWK Improved system. The first time we had a dead set of batterys, in a 60 KW, well we jumped it off from a 45 KW we still had on hand. Sadly, we never noticed that the 45 KW was Positive frame ground. And the 60 KW was Negative frame ground. Like magice, a bunch of wire on the 60 KW smoke tested. Burnt to a crisp. Sadly, we hooked the 45 KW up to a SECOND 60 KW, because we did not understand what had happened. But we began to get the idea after the second 60 KW burnt up the wire harnes between the special relay box and the batteries. Oh yeah.
 

Sharecropper

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Thanks for that story. Glad the American taxpayers took care of things.

I understand that our CUCVs are 12-volt negatively-grounded to the frame, I get that. I was just wondering if there was any issue with returning 24 volts back to the frame through the starter. Evidently not, as it has been doing exactly this in thousands of CUCVs for 35 years or more.
 

MarcusOReallyus

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I understand that our CUCVs are 12-volt negatively-grounded to the frame, I get that. I was just wondering if there was any issue with returning 24 volts back to the frame through the starter.
No reason you couldn't add a 48 volt and a 96 volt system on the beast, in the same way. You could even run some kind of AC generator on it and use the frame as your neutral. No problem. Multiple voltages on a circuit is done all the time.
 
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