Came up with the simple wiring diagram to test start an engine on a test stand. I want it simple...Just start and run to check engine condition.Am I missing something or should it do the job. Please see my rough design attached.
You might find moving the wire from "I" on your solenoid to the coil side of the ballast resistor will help it start easier though.
You can also run a wire from the "exit" or "load" side of the starter button directly to the coil to bypass the ballast resistor. What this will do (I think??) is give full "power" to the coil during the time that the engine is being turned over by the starter. The drag the starter motor puts on the battery could reduce the voltage available to the coil for the best spark. I had to do this with my old 9N Ford Tractor to insure a quick start, especially when it is cold. As soon as you take your finger off the starter button it drops that wire out of the circuit and allows the ballast resistor to do it's job. I probably didn't use all the correct terminology but it worked for me. SIDE NOTE: Not trying to hijack the thread but if anyone sees anything wrong with this approach/method please chime in. I would hate to mislead anyone, but as I said, it appears to be working for me.
Fan Attic has the same idea as I do it seems.....just a different way to approach it. Not sure mine is the best.....but the principle is the same. He just typed it quicker than me.
Fan Attic caught the only error in your diagram. It bypasses the ballast resistor when cranking the starter for full 12 volts to coil, only when starting. On run power then goes through the ballast resistor to save the points from burning. I need to type faster!
Just to confirm...I should REMOVE the wire that I had going to the "I" side of the solenoid and run it directly to the coil side of the ballast resister? Then NO wire is needed from the on of switch to the "I" post of the solenoid.Correct?
Run the wire from the I terminal on the solenoid directly to the + terminal on the coil, or run it to the terminal on the ballast resistor "outlet" side. When the solenoid is energized, there should be battery voltage present on the I terminal. I hope that makes sense.
The Ballast Resistor will be in the wire that is marked "From Ignition Switch "Hot" in the Run Position.
Yes sir that should do it! Now get to wiring and show us a video of your test stand and the engine running. Coincidentally, I am working on mine today as well.
The test stand doesn't care. Visualize it like it is just a section of the chassis of the car that the engine is going in, and wire everything accordingly.
Not for a simple test stand; just hook up the wires properly and go. I can't think of any component on the stand itself that is polarity sensitive. However, a dual voltage/dual polarity test stand like I need, is a whole different ball game. The only change I would make on the O/P's second diagram is to have a separate SPDT switch to cut in and eliminate the ballast resistor when running. It can sometimes be helpful.
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