getting ready to start 27 t and looked down to see no cut out switch on generator. Put in a 5055 from Lang's. went to hook up neg bat terminal and got a spark. Key is off, headlights or horm not wired yet. Engine not running for fear of frying generator. Tested cutout by grounding case and putting 5 volts to commutator connection get 5 volts on other side of cutout terminal. switched leads sending current in opposite direction and still get 5 volts. Is cutout defective??
The 5055 is listed as the diode version. The claimed 5A rating seems a bit odd.
The ground connection has no function with the diode cutout.
To test this cutout, connect a test lamp in series with it to a battery. The lamp should light up with the cutout only one way round. If it lights up with the cutout both ways round, the diode is shorted.
Maybe I misstated what I did. I applied 5 volts to one side of diode and measured 5 volt on other side of diode. applied 5 volts to other side of diode and read 5 volts again. I switched power lead from one side to other and got voltage in both directions.
Sorry for my ignorance. I did what you suggested and the cut out lights up only in the proper direction. Thanks.
Sounds like the cut out is ok then.
Just one thing, make sure it's the negative battery terminal that's grounded. Unlike the original mechanical cut out, battery polarity is important.
These diode cut outs are also made for Model A's using a positive ground system which has sometimes caused confusion. I note that the Lang's part is negative ground however.