half-speed forward suddenly?

[little1406]

year 2000 EXGO Workhorse (series motor) suddenly will only go half speed forward. Reverse seems normal, which is usually half of full forward speed. Found ITS test procedure here on BGW forum, tested mine, bad results: 1.5v initial voltage increasing to 2.5v at full throttle. Ordered new ITS. New one gives precisely the same readings. Tried a new motor, same behavior. Controller is Curtis 1205-117 with 4 small wires (1, 2, 3, and an unlabelled 4th one). Forward-reverse switch is OK, at least the high-current part. Not sure about the two microswitches, except that forward and reverse still work, just half speed in forward.

Any ideas what might be wrong here?

[JohnnieB]

The fourth small wire on the controller is for 1/2 speed reverse, but it will put controller into 1/2 speed whenever voltage is applied to it.

Disconnect the wire on the fourth terminal (Orange) and see if cart runs at full speed.
If it does, you may have a bad microswitch on the F/R assembly, or a wiring issue.

If it doesn't, let us know and we will troubleshoot further.

[JohnnieB]

Originally Posted by little1406

year 2000 EXGO Workhorse (series motor) suddenly will only go half speed forward. Reverse seems normal, which is usually half of full forward speed. Found ITS test procedure here on BGW forum, tested mine, bad results: 1.5v initial voltage increasing to 2.5v at full throttle. Ordered new ITS. New one gives precisely the same readings. Tried a new motor, same behavior. Controller is Curtis 1205-117 with 4 small wires (1, 2, 3, and an unlabelled 4th one). Forward-reverse switch is OK, at least the high-current part. Not sure about the two microswitches, except that forward and reverse still work, just half speed in forward.

Any ideas what might be wrong here?

The controller determines the ITS voltages, so you must have been looking at the ITS voltages for something other than a Curtis 1205-117 controller.

Pedal up for a 1205 is 1.4-1.5 Volts and pedal down is 2.4-2.8 volts.

[little1406]

Thanks, Johnnie!

You certainly nailed it. Disconnecting the 4th wire on my 1205 restored full speed forward and, of course, now I have full speed reverse which could be very useful around here since we have to back up hills from time to time.

I found a 1204/1205 manual online but I could not find any reference to the 4th wire in it, nor to the correct ITS voltages. Now I have two good ITS.....

It's surely the microswitch on the F/R switch. That thing looks like it's been around the block a few times.

Thanks again.

Scott

[JohnnieB]

Originally Posted by little1406

1. I found a 1204/1205 manual online but I could not find any reference to the 4th wire in it,
2. nor to the correct ITS voltages.
3. Now I have two good ITS.....

4. It's surely the microswitch on the F/R switch. That thing looks like it's been around the block a few times.

1. It depends on the suffix. I think the ones with 1/2 speed reverse (4th control wire) were specially built for EZGO, but I might be wrong.

2. I don't have any Workhorse manuals in my stash, but several carts used that type controller and the drive systems were all wired about the same. Do you have a 36V or a 48V system? (I'll post a schematic for it)

3. Hold onto it, it may come in handy. Or you could sell it, all the EZGO carts the have an ITS throttle system use the same sensor.

4. I think you are right. The microswitches are pretty fragile.

[little1406]

It's a Curtis 1205-117. It makes sense that it was made special for EZGO.

Mine is a 36v system.

I'd love a correct schematic. I've got lots of sorta correct ones.....they're not as much help as you might think.

Scott

[JohnnieB]

Sorry, this may fall into the sorta correct category also.

I don't know how a Workhorse is wired, but EZGO used the same basic design over and over with little change.