# Problem with Nordskog 36v 'controller'



## major (Apr 4, 2008)

RockHillWill said:


> I am new at this forum, this is my first post. I am seeking help with an issue that I am having with a very old Nordskog 36v 'service' cart. I know VERY little about battery powered carts, and am mechanically inclined' but know next to nothing regarding electronics.
> 
> The cart has new (expensive) batteries, the motor has been rebuilt/serviced and load tested to be in good condition. My wife and I have taken every? wire connection loose and cleaned them. The charger works and I am able to monitor that the voltage is above 36v. I have a manual, and the troubleshooting area indicates a possible problem with #1, #2 or #3 diode.
> 
> ...


Hi Rock,

Some pictures would help. I suspect you (the cart) have resistor speed control. The coils of which you speak are likely the resistors which are switched in via a sliding contact moved by the throttle. Slowest speed will have current going thru all 3 resistors (coils). Top speed should bypass all resistors. 

When those resistors (coils) are in the circuit being used to run slower than top speed, they will heat up. When they get hot, the resistance goes up and the speed goes down. It sounds like that happens and when you wait a few minutes, the resistor coil cools and cart speed is higher. 

The types of controls work best when used at top speed. If perhaps the throttle slider is out of wack (alignment) and not switching out all the resistor coils, symptoms would be as described. 

Post some photos. Also jack up drive wheel and check out operation of the throttle. Be careful. Resistors can be hot enough to burn.

Regards,

major


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## RockHillWill (Jun 17, 2017)

Thank you for your reply, Major.

Here are four pics of the 'electricals'. We disassembled the foot pedal control box shown and cleaned all the contacts and replaced the rivets/moving contacts. We can feel and hear as they go from one connection to another.

This afternoon we removed the diodes, but I do not know how to determine what the 'value' is. All three have the wide gray stripe, but I am unable to read the numbers. I think I can figure out how to test them.

Thanks again for your help.



































Will


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## major (Apr 4, 2008)

Hi Will,

From the photos (thank you very much) it is resistor speed control. It uses solenoids (aka. Contactors or power relays) instead of the sliding power contacts which I was describing. The throttle then pushes some type of contacts or switching device to energize the solenoids which do the power circuit switching. You can search for diagram or schematic (I used google image search). http://www.vintagegolfcartparts.com...?func=show&file=200339&Category=100020&Page=1 

I suggest you get a multimeter. Just saw one at Sears for $10. Using it you can determine functionality of the solenoids and even test the diodes. Diodes are flyback or freewheeling to reduce arcing on the contacts or switches; not critical to circuit or responsible for your problem. Here again a google search for flyback diode will help you understand. 

If you are just interested getting the cart running and not an historical restoration, I recommend wholesaling out the resistor control and installing a modern speed controller like Curtis 1204 or Alltrax. Actually such a project is a good starting point for EV DIY. Or a golf cart shop may be hired to do it for you.

Regards,

major


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## RockHillWill (Jun 17, 2017)

Thanks again, Major, for your time.

I am an experienced restorer of vintage autos, etc, but this project was undertaken at the 'request' of my wife. LOL! And she is adamant that it is done as original. We live on some acreage and she raises goats. I got it for her as a present, and this 'problem' is preventing me from turning it over to her.

I do have a multi meter. We pulled the diodes and tested them at the dial setting as shown. But no matter which way I held the wire leads I got 00.0 and no 'beep'. I tested the multi meter batteries as good and when I touched both leads together I got the 'beep'. I do not understand why all three of the diodes tested the same (good or bad?). We reinstalled the three diodes.

When we take it out for a test, it looses power in about one minute of use, and the lowest and largest diameter wire resistor would get real hot. We discovered that the lower mounting bolt might have been grounded and repaired that issue. We jacked up the back wheels as you suggested and it took about three minutes (not under load) to stop running, but that lower resistor did not get hot at all.

Reading the trouble section of the manual, this issue seems to indicate a bad diode, but I do not understand how all three 'tested' the same.

I have located a parts source for this cart and I have ordered three new diodes.









Thanks again for your time.


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## major (Apr 4, 2008)

If this screen shot is how you tested diodes I think you missed using the select button to scroll. A diode icon needs to appear on screen.


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## major (Apr 4, 2008)

Other things which come to mind:

High resistance connection like due to corrosion or otherwise poor contact.

Solenoid malfunction. Are they 36V rated control coil or 12V? Possibly welded contacts (internal)? Properly closing (turning on)?

Reversing switch problem....

When testing with wheels spinning (jacked up), verify 36V at battery. In top speed you should get nearly 36V across the motor. The motor measurement will likely need to include reversing switch. Measure voltage across other components. As it slows or shuts off, and battery is still 36V, motor will be 0 or very low voltage. There will be anothe place in the power circuir showing a high voltage drop. Like a break (called an open) will read 36V same as battery. You should be able to track down the fault.

If you have difficulty following me, try to find an on-line tutorial on resistor motor speed control.

major


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## RockHillWill (Jun 17, 2017)

Major , I/we REALLY appreciate your help. I feel that am able to follow you. (so far anyway, LOL)

I do understand corrosion vs contact ability. We feel like we have disassembled and cleaned EVERY wire connection. It took all day!

We have removed and scraped clean the entire reversing switch assembly.

I will pursue the multi meter suggestion.

I have tested no solenoids. Will pursue that matter.

Regards, Will


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