Cushman electrical problem, HELP!

poppa

I think this is a rectifier , it sparks a lot when I shut off the cart. What's wrong???

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CharleyL

Yes, that is a rectifier and it should not spark. Is that yellow wire with the blue crimp connected to anything? It looks like it has broken off of the terminal just below the blue crimp.

Rectifiers are used to convert alternating current (AC) into direct current (DC) and it's frequently part of a battery charger where a transformer steps down the AC power from a household electric outlet, producing a lower voltage of usually 24 or 36 volts AC. When this lower voltage AC from the transformer is passed through this rectifier, It converts the AC voltage into DC to charge batteries.

Some carts with gas engines have alternators that produce AC power when the engine is running and this AC power is then passed through a rectifier to convert it into DC power to charge a battery. The rectifier shown in your picture is made from selenium. Newer rectifiers are made with diodes and are more reliable.

Charley

poppa

Charley , Thanks for the quick reply. No ,it is connected. The red one goes to the ignition switch ,the two yellow ones on either side of the red one go to the inside of the engine ,the last one on the very bottom right (connected to the "wire" that goes from front to back) is going to ground. This cart had an engine fire before I got it ,so I wired as best I could from schematic. Any suggestions? Does it make a difference on the two going into the engine? Thanks

poppa

With my multi meter ,it shows it is charging.

CharleyL

If it's the rectifier to convert the alternator output to DC and the battery is charging it is most likely wired correctly. The rectifier is called a "Bridge Rectifier" and it has 2 leads from the alternator for input and then 2 wires for the output, one is the positive lead and one is the negative lead. The negative lead should go to the chassis or - terminal on the battery and the plus or + lead should go to the plus terminal on the battery, but through the ignition switch. I can't think of any other reason why there would be another rectifier in a Cushman. Newer alternators have a diode rectifier built and a voltage regulator into the alternator so none of what you have is necessary. Something you might want to consider if you have any problems with your selenium rectifier or alternator.

Charley

CharleyL

So where are the sparks coming from? A selenium rectifier is not supposed to make sparks.

Charley

poppa

The sparks are around the "plates" mostly. You can actually see some burn marks from the sparking.They also appear to come from the "spacer" in between the "plates" ,in pic they are green.

So the wires coming from the altenator (in engine) can be reversed?

If this is not a problem with somerthing else , can I just get a new rectifier? Recommendation?

CharleyL

I would replace it, but I would replace it with a diode bridge rectifier, if it was mine. The trick is to find a diode bridge rectifier with an adequate rating. Do you have any information such as the specifications that lists the manufacturers part number (not Cushman #) or the voltage and ampere rating of that selenium rectifier? Yes, the wires coming from the motor are AC so they can be connected either way, if they are not grounded inside the motor. A quick ohmmeter check will determine this. The + and - wires must be connected correctly. You cannot interchange them.

Charley

poppa

No sir I do not. I had it off to look it over and saw no markings/specs. Now what ??

CharleyL

is there anything in the cart documentation that might indicate the charging amperes, or possibly a fuse size? What year and model is your Cushman? Maybe I can find something about it. Do you have a Cushman part number for it? Maybe we can find the specs for it that way.

Charley