The Ford Barn - View Single Post

Tom Wesenberg · 10-01-2012, 05:29 AM

First DON'T use a digital meter for your tests. ONLY use a good analog meter.
As mentioned the stock cutout, or diode cutout is a simple OFF-ON switch (relay) that closes the contacts when about 6 volts from the generator is reached. It has no regulation and doesn't care what the battery voltage is. A good generator should be able to charge the battery as long as the engine is running about 475 RPM's or more. Even is the engine was running at 100 RPM there should be some voltage showing at the output stud, but it might only be a volt or two.

Since your generator had output, but now doesn't after the shop motored it, either he messed up something, or you may have left the insulator off the cutout for the angle bracket that is fastened to the generator output stud. Without the insulator on the cutout terminal the generator output stud will always show 0 volts, since the output would now be grounded. The thin insulator goes on the input (generator stud) side, and the thick insulator goes on the output side of the cutout. Be sure you don't use screws that are too long on the cutout terminals, or they may screw into the cutout windings and short them out.

Vince is saying that 0 volts should show ACROSS the cutout terminals. In other words the voltage drop across the cutout terminal should be 0 volts. In reality there is a very small voltage drop such as .1 volt or less with about 5 amps current flow. A cheaper repro cutout may have .2 or more volts dropped across the poor quality contacts in the cutout.

10-01-2012, 05:29 AM	#130
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Is There An Electrician In The House? First DON'T use a digital meter for your tests. ONLY use a good analog meter. As mentioned the stock cutout, or diode cutout is a simple OFF-ON switch (relay) that closes the contacts when about 6 volts from the generator is reached. It has no regulation and doesn't care what the battery voltage is. A good generator should be able to charge the battery as long as the engine is running about 475 RPM's or more. Even is the engine was running at 100 RPM there should be some voltage showing at the output stud, but it might only be a volt or two. Since your generator had output, but now doesn't after the shop motored it, either he messed up something, or you may have left the insulator off the cutout for the angle bracket that is fastened to the generator output stud. Without the insulator on the cutout terminal the generator output stud will always show 0 volts, since the output would now be grounded. The thin insulator goes on the input (generator stud) side, and the thick insulator goes on the output side of the cutout. Be sure you don't use screws that are too long on the cutout terminals, or they may screw into the cutout windings and short them out. Vince is saying that 0 volts should show ACROSS the cutout terminals. In other words the voltage drop across the cutout terminal should be 0 volts. In reality there is a very small voltage drop such as .1 volt or less with about 5 amps current flow. A cheaper repro cutout may have .2 or more volts dropped across the poor quality contacts in the cutout.