2004 PDS motor testing

1fatcat

Does anyone know what the motor field windings should ohm check at? I had very bad brushes in my motor so I had a local shop rebuild it with new brushes. The burnt brushes did a number on the commutator, so they machined it down too. The cart moves now (didn't move at all before rebuild) but it only goes about 5 mph.

I borrowed a service repair manual and get to the step of checking voltage across the field windings (should be 2.2~3.2v) and I get 1.3~1.4v. The flow chart in the manual says to replace the motor at this point. I ohm checked the field windings and get a reading of 1.0 ohms. The manual does not give a spec for this (that I could find anyways).

Some info on the cart and what was done: 2004 EZGO 36V PDS, batteries are 3 years old and read 37.7 after charge. Solenoid was replaced 1 year ago and passes the test in the manual. I've tripple checked all the wiring and have charged the batteries 3 times since the rebuilt motor was installed. I've only driven it about 1~2 miles since the motor was put back in, so the batteries haven't even had a chance to drain yet. Even right after a full charge, it will only go about 5 mph.

Please help! I can give more info on whatever is needed, just let me know and I will get the test results.

BGW

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Spawn

Speed sensor maybe, its in the back of the motor. Contact Plumquick tomorrow and maybe they can tell you what value you are looking for since they rebuild Cart motors for a living.

JohnnieB

What Spawn said about the motor.

On the other hand, I see a bright red flag waving in the 5MPH breeze generated by your cart.

For a 36V battery pack, 37.7V indicates the State of Charge is less than 90%, rather than being fully charged.

What are the individual battery voltages?
At 37.7 V they should be about 6.28V each and shouldn't vary more than 0.1V between batteries.
At a Full Charge (38.2V), they should be 6.37V each.

Also, what is your battery pack voltage while setting still vs moving at 5MPH?


You might have some motor issues, but I think you've might have some battery issues too. New batteries go bad also.

Let us know what you find out.

Added:
Have you tried running cart in Diagnostic Mode?
That might tell you why it is going so slow.

1fatcat

It was the controller. I took a $350 + tax gamble and I won! That was the first time I've ever won taking a gamble. Thanks for the advice everyone.

1fatcat

Sorry, I didn't have much time to type up the whole story yesterday. What lead me to believe the controller was faulty was that the solenoid would click as soon as the direction switch was placed in forward or reverse. It shouldn't click until the accelerator pedal is pressed, triggering the micro switch in the pedal box. I unplugged the pedal input connector at the controller, and it still clicked the solenoid with the direction switch input. So I figured that the controller was bad because it was activating the solenoid when it shouldn't be.

On a side note, the new controller no longer has regenerative braking? There is no plug installed, so it should be in "golf" mode? I thought there should be regenerative braking on a stock controller?

scottyb

What controller did you get?

JohnnieB

Only the Mild Hill and Steep Hill have Regen Braking, All Terrain (Golf or no plug) and Freedom do not.

Use the plug from your old controller or order a new one if you sent it in with the core.

1fatcat

I just got a stock remanufactured controller from the local ezgo dealer. The old controller had no plug at all, so I guess thats another sign that was slapping me in the face. I had no idea it should have free wheeled? It's actually a neighbors cart that I told him I'd work on. I'm normally an auto mechanic, so these are a little different to me.

JohnnieB

If you can work on the cars with computer controlled everything they are building these days, carts ought to be a piece of cake for you.

Except for the mechanical brakes, the cart's running gear is straight out a 1940's Automotive Engineer's handbook.
The motors are either series wound or shut wound designs that have been around since the 1900's or earlier.
The electronic speed controller is basically a light dimmer switch on steroids.

Yeah, they are a little different, but once the fog lifts, they are fairly straightforward machines.

Here's a link to the Operator's, Service and Parts manuals for the cart you're working on.
http://www.buggiesgonewild.com/elect...g-manuals.html

Attached is an illustration of the different plugs for the four different PDS modes. Same plug with different pins jumpered. You can get them for $5-$10 apiece.
The different modes are described in the Operator's manual and in the Service manual.

Attached Images

PDS J2 mode plugs.jpg (130.2 KB, 4 views)

yurtle

I don't have a PDS, but this thing appears be be aching for a rotary switch to change between modes. WAY cheaper too. Not sure if you can change on the fly, or have to power down (reboot) between changes.