Resistor cart wiper arcing - symptom or cause?

[rlw]

Coosa - I sent you a PM.

[scottyb]

Just a bit of humor. Not every cart needs an upgrade. People prefer what they are familiar with until they become familiar with the new thing than they won't give it up for the next thing. Look at the toilet for example. Many people weren't going to do their business in the house - for cryin out loud! Those same people preferred hay and leaves to that new paper on a roll But I digress.
I do miss the old rotary phone we had when I was growing up. It had a certain pattern it would click when I called my sweetheart... but it never remembered her # or told me the news or weather.
Sure new technology has new problems - but it's a lot more versatile & easier to get parts for if and when you need em.

Enjoy the ride

[rlw]

ScottyB,

Humor appreciated. I've got a fancy smartphone AND that new-fangled paper stuff on a roll, but I still like my '84 Marathon as-is!

;^) <====== AND I still use old-school emoticons!

[yurtle]

Originally Posted by scottyb

Just a bit of humor. Not every cart needs an upgrade. People prefer what they are familiar with until they become familiar with the new thing than they won't give it up for the next thing. Look at the toilet for example. Many people weren't going to do their business in the house - for cryin out loud! Those same people preferred hay and leaves to that new paper on a roll But I digress.
I do miss the old rotary phone we had when I was growing up. It had a certain pattern it would click when I called my sweetheart... but it never remembered her # or told me the news or weather.
Sure new technology has new problems - but it's a lot more versatile & easier to get parts for if and when you need em.

Enjoy the ride

Corn cobs and the best was the new Sears catalog, so the old one could be used.

[rlw]

Well....

I took the wiper board assembly out to my buddy's machine shop and he had one of his guys mill down the fixed contacts and the wiper contact. They're probably in better shape now than they were when I first rebuilt the thing a couple of years ago. He only took off about a tenth of a millimeter.

I haven't installed it yet, but my guess is that it'll run better than it ever did, since I didn't originally get the contacts milled the first time. Did it all with a bench grinder and some 300 grit sandpaper by hand. It's important that the tops of the fixed contacts are flat and in the same plane, as well as the wiper contact being perfectly flat. The milling machine did all that this time.

I'll report back after I put it all together.

Before and after pix below...

RLW

[tjequip]

That looks a whole lot better. Hope it works as good as it looks.

[rlw]

So.....

I put everything back together and NUTHIN'!!!! Not even a reverse beep. After some head scratching - turns out I forgot to connect the S1 cable from the motor back up to the battery pack negative post -- it was hanging under the battery tray where I couldn't see it. Did a cranial-rectalectomy (Latin for "removed head from butt"), hooked up the S1 cable and gave it a try.

Still have MAJOR arcing and no movement until I hit either the third or fourth contact on the wiper board.

I had the buggly in the garage, FNR switch set to "R", beeper-a-beepin' and hit the pedal. Arced like hell when the pedal was about 3/4 down, lurched backward and smacked into my old dead Mazda B2200. Lucky it's an old, dead Mazda (IT might be a candidate for "Bugglies Gone Wild!")

After I changed my pants, I did a visual inspection of the resistor (again). Looks fine, but it could be that there's a break I can't see without yanking the dang thing outta the cart.

I'll do that tomorrow. I've had enough fun being a cart-whisperer for one day.

RIB's suggestion up above about checking the resistor makes sense now, as it would arc like that if the first or second (or even third) low-speed resistors had a break in 'em.

Normally, you depress the pedal, 3/4 of the current gets dumped into the whole resistor, and the motor starts up slowly. Push the pedal a little further, now half the current is in the resistor and the other half is coursing its way through the motor. Push more, 3/4 is in the motor and 1/4 in the last resistor coil. Floor it, and all of it goes through the motor.

If the first one or two chunks of the resistor are out of the loop, then ALL (or ALMOST ALL) of the current goes through the motor from a dead stop when you get to the third contact, and that would cause the arcing. It didn't look like I burnt up my new shiny contacts, though.

I'll know this weekend if RIB's suggestion and this theory pans out.

RLW

[coosa]

Do you have a short cable running from the first contact that carries current to the solenoid? The cart will run without it, but it greatly reduces the arcing. All the wiring diagrams I had seen didn't have it; didn't know about it until I saw a diagram on here.

It does sound like you have another issue. Hey, I offered a solution. Just say the word. :)

[rlw]

Coosa,

Yeah, I do have that cable. Gonna pull the resistor today and take a look. It could also be a cable going back to the resistor - they ride alongside the motor. I'm going to ohm each of those out, too.

RLW

PS: I appreciate your offer, but still want to wait a bit. Thanks again.

[coosa]

Originally Posted by rlw

Coosa,

Yeah, I do have that cable. Gonna pull the resistor today and take a look. It could also be a cable going back to the resistor - they ride alongside the motor. I'm going to ohm each of those out, too.

RLW

PS: I appreciate your offer, but still want to wait a bit. Thanks again.

If you have that cable and it still arcs on the first 2 contacts and the wiper works fine on high speed, then I think its likely to be an issue associated with the coil; either the coil itself or a cable going to it. Or it could still be in those first contacts; they can look good and still not work.

I have a brand new coil in my box of resistor cart goodies; never even been installed. I think I also have all the cables that run to it. I'm tired of looking at all this stuff in my shed when somebody could be using it. If you will pm me your address, I'll drop it at the post office Monday - no charge. I''ll pay the shipping as a way to thank the forum for all the help I've gotten here. It was sure worth a lot more than a flat rate shipping fee.

You ain't gonna beat that deal.