98’ Club Car 48v, sudden power loss.

[Captkonradb@aol.com]

First off, thank you all for your great guidance over the past few years, I’ve never had to actually ask a question, you’ve help me fix a multitude of problems with just a search!! But I I’m going to have to ask this time....

I have the above mentioned cart, newly rebuilt, running perfect. I Hit a bump today and cart shut off, no forward or reverse movement.
I Have 51 vdc, on the “IN” and “OUT” side of solenoid, to negative terminal on battery pack (this is after over an hour of driving).
Power to, and through solenoid. Solenoid has good continuity when energized and none when not (tested out of system). Resistor on high current side shows 240 ohms of resistance and the diode on the coil side checks good one way and not the opposite. (Typical diode)
Can you tell me what I should be reading, (voltage-wise) at the four motor terminals, while in either F+R switch configuration?
I’m sorry if I don’t explain this very well and I appreciate your help.

[NoleFan4Ever]

I would inspect ALL the cables first and foremost. Check the ones going to the FNR switch, the controller and especially at the motor.

If all them visually check good, then please verify the solenoid is closing (clicking loud) when you have the key On, in Fwd, and Go Pedal depressed.....

Operating off the cart does not mean you are getting the Pos and Neg permissives to allow it to operate (close) the field coil while on the cart.

And the voltage check on the solenoid should be 1 to 1.5 volts less between the battery and controller side of your large posts and then come up to full (even) pack voltage after it closes in. Your Pre-Charge Resistor in place and allowing a small charge to the capacitors in your controller.

[Captkonradb@aol.com]

NoleFan4ever, thanks. I had wondered about the reason for the resistor between the the two high current post on the solenoid.
I did notice that the connections at the FNR seem not to be as robust as I remember from other carts. I’ll do some continuity checks there this morning, but the motor connections are tight and solid.
One thing I will mention is during deceleration I can hear something from the motor\axle area that sounds like a rubbing or maybe a bearing, but only on deceleration, does this sound like anything that could assisted with this sudden power loss?

[Roxyflash]

I would jack the cart up release brakes turn each wheel by hand both directions check for drag possible brakes are dragging on rear axle

[NoleFan4Ever]

As Roxy mentioned, that sounds more like your brake drums then anything, but it ~could be motor brushes or the motor bearing being a little noisy as they are more prevalent when off throttle and coasting as there is no power being applied to the motor.

[Captkonradb@aol.com]

I will definitely check that....if I ever get this thing rolling again.
So I have determined that the connections are all tight at the FNR and the motor, I have good continuity across the FNR as well.
I took some voltage readings and I really don’t understand why I have full (50.3vdc) at all four motor terminals when the FNR switch is in the nuteral, forward and reverse position. The only voltage change is when the key is on and FNR switch is in F or R and I depress the go pedal, then I have a one volt (49.5vdc) drop on each of the terminals.
Does this sound right? I would have thought that one or more of the terminals would have zero voltage until the GO pedal was depressed?
Again, thanks for you time!

[Sergio]

Originally Posted by Captkonradb@aol.com

I will definitely check that....if I ever get this thing rolling again.
So I have determined that the connections are all tight at the FNR and the motor, I have good continuity across the FNR as well.
I took some voltage readings and I really don’t understand why I have full (50.3vdc) at all four motor terminals when the FNR switch is in the nuteral, forward and reverse position. The only voltage change is when the key is on and FNR switch is in F or R and I depress the go pedal, then I have a one volt (49.5vdc) drop on each of the terminals.
Does this sound right? I would have thought that one or more of the terminals would have zero voltage until the GO pedal was depressed?
Again, thanks for you time!

That is not possible on a properly wired Series Club Car unless either the Motor has an internal short or the FNR is broken and the contacts are welded.

The 2 cables on the swivel posts of the FNR should go to Motor S1 and S2, so when the FNR is in Neutral, there can be no voltage on those terminals.

You will always have power on A1 and A2 if the Armature is good since A1 is directly connected to Controller B+.

The noise during deceleration can also mean You need a new "Motor bump bushing", sometimes referred to as a motor "centering kit" as well.

[Captkonradb@aol.com]

Sergio,
Thanks so much. This didn’t seem correct to me and you’ve confirmed it now.
I wonder if when I hit the bump yesterday, i didn’t break a connection internally in the motor. I’m going to ring out the FNR one more time but there doesn’t appear to be anything welded or fused together.
Thank you very much for the run down on where I should be seeing voltage, that’s a huge help in pointing me in the right direction.

[Captkonradb@aol.com]

Well Sergio, I was mistaken when I thought the FNR switch was in the neutral position, it wasn’t and hence the voltage at the motor terminals. The FNR is a little tough to find the neutral exactly.
One more thing I wanted to ask about, that seems strange, is that with my negative lead from my meter, on the negative terminal on the battery pack, I can read 50vdc on the frame of the cart. Do you think this could indicate a short in the motor?

[Sergio]

That is one possibility if is a low resistance path, but most of the times what your meter is reading is due to a high resistance path caused by dried electrolyte around the batteries or caked up brush carbon dust around the commutator.

If You use a low impedance meter or place a small load in parallel with the meter probes you will not get any voltage if it is a ghost voltage.

If you have not cleaned and neutralized the area around the batteries it is a good idea to do so.

Since the motor is 20 years old You could also blow the inside clean and inspect for damage.

Did You do the test that NoleFan4Ever suggested, measuring the voltage across the pre-charge resistor after the Solenoid clicks?