It means that there is one obvious terminal and that one goes to the positive side of the battery. The case connects to the negative side of the battery. In other words, it is designed for a negative (side of the battery connected to) ground system.
I am wiring a car windshield wiper motor directly to a car battery. The wiring diagram says +12v Terminal1 -12v case grounded Does that mean to connect positive lead to terminal one and the negative lead from the battery is made to contact the case, probably at the mounting bolt? I realized that is probably as basic a question as it gets, but if you don't know?
Thanks Pat
Thanks. Works like a charm. Now I'm curious why you don't toast yourself, or at least get a thrill when you grab the engine block.
A1: You don't complete the circuit. In order for any current to flow you need to touch both terminals of the battery, and when you touch the engine block you are only connected to one of them.
A2: 12V is too little to feel anyways, unless you stick it on your tongue. Though you could do some arc welding if you put a screwdriver across the terminals (because a very high current is available).
Jonathan
You need to be touching two different potentials with the difference large enough to drive at least a milliamp or more through you before you feel a shock. Dry skin resistance is normally in the 10s of thoudsands of ohms. 12 volts can't push enough current through that to be above the threshold of sensation. Most people start to feel a tingle somewhere between 40 and 70 volts across dry skin. Your tongue requires much less. If you puncture the skin (or it is wet, especially with salt water), much less is needed for a shock.
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