Dear,

I'm in Mauritania. I try to repear an forklift hyster electric J2..oxnt. up and down the boom of the forklift without problem. But no traction in forward or reverse. All time i see in the screen sybole of parking brack.

Please if you have any information for this anomaly give me a help.

If you you have a document for this forklift can you send it to me.

Best regards.

Dear,

I'm in Mauritania. I try to repear an forklift hyster electric J2..oxnt. up and down the boom of the forklift without problem. But no traction in forward or reverse. All time i see in the screen sybole of parking brack.

Please if you have any information for this anomaly give me a help.

If you you have a document for this forklift can you send it to me.

Best regards.

Ok final conclusion from crown is the motor is bad, but is unclear whether controller is bad also. Just thought i'd let you know.

Thats ok I think it was more my inexperience at troubleshooting. We've had two different crown mechanics that could diagnoss the problem and haven't been able to get them back to continue working on it. If we ever figure it out i'll let you know what the problem was.

Sorry i wasn't able to walk you through this one.

I tried...

I don't feel so bad now, even the crown mechanics are having trouble figuring this one out.

My supervisor finally decided to call in crown to troubleshoot this pallet jack, so i just wanted to say a big thanks for all your help.

I appriciate all the advice you given, it is truly appriciated. I am not an electrician nor a trained forklift machanic. I apply what little electrical knowlegde taught to me when i workded for an A/C company. This unit if the first one to really stump me. I figure i've been able to diagnose or repair at least 95% of problems encountered with our 17 forklifts. Major repairs i leave for crown. Now i will go apply what you wrote and see what i find, thanks again.

in my last post, i was having you go through the traction circuit looking for something open.
Measuring from the battery positve, ideally you should see <.5 volts to the first post (the one directly hooked to the batt pos.)
Going to the a2 post on the motor, you should see upwards of 6-10 volts, IF everything was working properly.(if the motor was working, then a magnetic field builds up, and creates resistance which will show as a voltage drop accross the load)

Since we've established that the motor does not work, even when shorting across the pmc, we are searching for an open circuit somewhere in the traction motor cct.

When you go across the open you should see battery voltage. Basically one side will be battery pos. and the other will be the neg, they just don't connect together.

So you were following the battery positive from the battery, all the way back to the m- post on the pmc controller.

If you saw roughly zero volts all the way there, then the problem must be on the negative side. The only negative side that could cause this, is the neg cable from the pmc to the standoff (my logic being that lift still works, so the battery is at least sort of ok, and the battery neg gets to the stand-off, because that's where they join together with the pmc cable and the lift motor neg cable)

When I say measure from the battery pos, I mean litterally from the positive cable where it enters the jack.

To check the negative, do the same, start at the negative cable.
Work backwards to the pmc, to the m- to the contactors, back through the fields, back to the contactor, back through the armature and to the battery positive.
Whereever you find 0 volts on one test, then battery volts on the next test in line, the problem lies between the 2 test points.

If you are not closing the direction contacts when loading (ie. shorting the batt neg to the m-) the you'll see the 12volt drop across the contacts.

If the problem is the traction fuse, then you'll see 12 volts across the fuse when you try to load the motor.

You really have to go step by step.

Most electric guys could find your problem in 2-3 minutes (not a cut or anything), and all they would do is start at one end, and go through the circuit till they find the problem.

Sometimes you are lucky and start at the right end, but most of the time you work our way through the whole **** thing before you find the problem.

So what my whole rant is saying, is that when you finally see battery volts, you've just passed the problem.

This might be a dumb question to ask, what type of voltage should i be looking at from the battery Pos. to each of the points you asked me to check? I only 2.591 vdc.

checking this points with only showing the 2.591 vdc as soon as i pull the handle down it drops to 0vdc before loading it and stays at 0vdc after loading it.

I'd bet you have a burnt cable where it wraps around the mdu.

Start with one meter lead at the battery pos (keep that one there), then check voltage to the pos. side of the armature, load it and watch for a voltage drop. Should be around 0 volts DC.
Move to the next armature motor post, try again. If you see a big voltage, then the motor brushes are to blame.
If ~0vdc, then move to then direction contacts, in particular, the bar the joins the 2 top posts.
Load it, ~0vdc= cable ok.
Then move to the bar that angles over the side of the contactor, on the side that you close with the the dir. switch.
Load it, ~0vdc= conator ok on that side.
Then follow the cable to the field post on the drive motor.
Load it, ~0vdc = cable ok.
Go to the other filed post on the motor.
Load it, ~0vdc = fields ok.
Then back to the dir. contactors, on the opposite angled buss bar.
Load it, ~ovdc = cable ok
Then to the 1 cable left on the direction contactor.
Then bottom one with the cable only.
Load it ~0vdc = contact ok.
Then move to the m- post on the pmc.
Load it, ~0vdc = cable ok

** when I say load it, try to drive the unit... close a direction contact and either trust the pmc, or short the batt neg to the m- terminal (with the wheel off the ground of course)

If you can pass all these tests & the motor doesn't drive when you close a direction contact while shorting batt neg to m-, then you screwed up somewhere and need to start again.

I was wrong, there is voltage at the contacts, tried again shorting the Neg. with M and it did not jump. I do have power at the contacts and motor. The motor armature is clean and brushes are fairly new. How can i isolate whether its the motor or contacts? I much appriciate the help you given me, Thanx.

If you close the direction contacts, short batt neg to m- and nothing happens, then it's a fuse, cable, contact, motor or battery.

You said lift was ok, so we can rule out battery.

When you say 'no voltage' at the contacts, how are you measuring it?

There should be a batt-pos there...
Basically, one side of the armature gets a pos, it goes out teh other side to the normally open side of the contacts (should be the bar that conects the top 2 posts)
When the contact closes, it puts that batt. positive onto one sid of the field, then back out to the other field contac, which will be normally closed to the m- post on the pmc.
The pmc chops that to batt neg to control current.
The A2 post of the pmc conects to the top bar of the contacts, to allow plugging current to pass throught the plugging diodes inside the pmc.

If all the wires are hooked up and powered properly and the unit jumps when shorting the m- to batt neg (with direction contacts closed) then it's likley a pmc.
If it doesn't jump, then it's in the cables, contacts or motor 100% for sure.

If it's pulling in both directions at the same time, you open up the motor circuit at the fields.
If the contacts are cabled incorrectly, then you'll have anthing from no travel, to 1 direction only, to both directions go the same way...

So long as the battery has ok voltage, don't worry about the charger thing.
If the battery is too weak, the contacts will chatter as load picks up, since lift is ok, this can't be the problem

Just follow that batter positive from the armature all the way to the pmc.
You might have a problem in the motor circuit that onl shows up under load, so look for a voltage drop while having the batt neg shorted to m- (with a direction contact closed of course)
Generally, contactor problems will manifest themselves with a problem in 1 direction oly, so you're probably ok there.
Armature and cable problems will be in both directions...

answers to your suggestions 1-7

1. ok
2. ok
3. ok new pot
4. with leads connected voltage reads 9.29 volts, pulling down handle it reads 11.84 and releasing handle it returns to 9.29.
5. I get no voltage at the field or amature
6. no voltage at contacts
7. shorting the two connection no results it didn't jump.

thanks for the respose, I will try what you suggested. It does have a curtis controller. Something else i was told today was that becuase it wouldn't move they connected it to a 24 volt charger rather than its assigned 12 volt charger.