Controller power wiring.

[gadavis]

Okay people. This is my first plunge into the solid state controller world. I bought a 1990 model marathon with an AllTrax NPX 300 amp solid state 0-5k controller. Cart is in good shape for it's age except for a broken plastic nose piece and some rusty spots in the battery box. I put batteries in in temporarily and will fix battery boxes later. I have an 89 model cart junked out back with a set of stainless battery trays that will go in this one.

My question is this: should the controller be wired up with power to it at anytime the key switch is on and the S-2 switch on the F-N-R is closed, or like they have it now so that the controller comes on when the-S-3 micro switch closes. The cart always takes off with a lurch the way they have it connected now. I adjusted the clearance to the stop pin at the top of the pot box arm and then determined that they had the solenoid activation wire and the wire coming from the S-2 switch on the same post. This has the solenoid activated when ever the Forward or reverse is selected and the key switch is on. Does the controller need current when not being used? The green LED blinks one time when the throttle is moved to on and at WOT. the pot. shows 535 k. Will this little bit of extra ohms make any problems?

[JohnnieB]

Having maintained electronic stuff for 50+ years, I lean towards leaving it wired as is.
Failures typically occur at power-up, so I'm not fond of turning the controller on and off (Powering up and down) with the pedal switch (S-3)

The solenoid doesn't close and applied a high current source to the controller until S-3 closes, so the lurch is being caused by switch (S-3) being out of sync with the potentiometer.

When the switch closes (solenoid clicks) the throttle input to the controller should be zero ohms, or pretty close to it. (I don't know the recommended value is for a NPX, but whatever it is, you've got more than you ought to have.)

I suspect your Ohmmeter is on the Ohms x 10 scale and you actually have 5.35k rather than 535k.
Again, I'm not sure of the NPX specs, but I'm almost positive it would think the pot was bad and shut down if the throttle input went much above 7k.

The one blink of the green LED means the NPX is set for a 0-5k throttle input.
When the LED turns to yellow (it may look more orange than yellow), it means the controller is sensing a WOT and is not passing max amps.

[gadavis]

Thanks J.B. for this Information. I moved the controller on wire to the side of MS-3 that comes from MS-2 as per the diagram from Ez-Go service manual and it comes on when the F-N-R switch is in Forward or reverse mode and is on as long as S-2 is closed. I wasn't overly pleased with the setup as it came to me. You are right about the 535. I looked at it again and decided I overlooked the decimal point. I keep my Fluke 77 meter on auto range measuring the ohms and I did it several more times and tweaked the pot box adjustment a little so that now the solenoid clicks on at about 7-10 ohms and maxes out at about 5.05k so I just left it there. I adjusted the linkage from the accelerator to the pot box to give the reccomended clearance. Ez-Go reccomends a clearance equal to a dime. I measured a dime with my calipers and found it is around .050 of an inch just to satisfy my curosity. After adjusting the stop clearance at the throttle box linkage and changing the controller power on wire to match the Ea-go diagram the cart starts off much smoother and is not as jerky when being driven. The controller light does turn yellow at about 3/4 throttle and doesn't register any higher ohms for the last 1/4 of the pedal stroke as per the book. Does all this sound correct? I found some info on the Alltrax NPX on their website and downloaded it for future references when I can't find you guys to ask questions of. By the way, I did all this with the cart on jack stands and not running WOT for more than about 15 seconds so as to not have the motor disintergrate.

[JohnnieB]

Sounds like you are getting it straightened out.

One thing to remember is that adjustment procedures and tolerances are typically written for new components and when working with mechanical stuff that has been in use for a while, you sometimes have to go with intent rather than the exact wording of the book.

Basically, when you push the pedal, the solenoid should click before the pot starts to increase in ohmic value, so you may want to use a "thicker" dime as a gauge.

[gadavis]

[QUOTE=JohnnieB; you may want to use a "thicker" dime as a gauge.[/QUOTE]


Thanks again for taking time to answer questions and give advice.

One thing I have learned from years of OJT-- AKA work, is that you need to get all the slack out of it if possible before you try to do any adjusting on it.

The only other manual I ever saw make reference to using a dime for a thickness gauge was in a manual for a Waukshau engine in an old crane dating around the early 40's. They stated to use a well worn dime as a thickness gauge for setting the ignition points in the magneto.


I have been around junk most of my life. I started out following my father working on farm equipment and you haven't seen "jury rigging" until you see what some farmer can do to finish plowing a field or some other much needed task.