Discussion:
Clark model ECL, large resistor smoking after a bit of use

I fixed (with the kind help of the gentlemen here) an issue with directional contactors not engaging, and got this truck working as expected.

Wiring diagram here: imgur.com/a/9ReVA (Copy and paste into browser address bar since I can't post a full URL link here)

However, after about 10 minutes of working it, I'm getting smoke from the large resistor that I'm presuming controls speed of the traction motor (?) and probably need to replace it. How can I determine the values I need for this resistor, as I'm fairly certain I can replace it with more standard modern resistors.

Also, should the hydraulic pump be working all the time? When I first got this, it seemed like it only came on as I used a control, then shut off a few seconds after demand. Not sure what the correct behaviour for this might be. From the diagram, it seems like it should be on 100% and perhaps the earlier behaviour was just a power issue.
  • Posted 20 Jun 2016 01:36
  • By ian_k
  • joined 16 Jun'16 - 6 messages
  • Ab, American Samoa
Showing items 1 - 3 of 3 results.
no pressure switches in this
very basic
switch at hyd control handle linkage
a contactor on the contactor panel

thats it
if it runs 100% of the time then one of those is shorted out
(slight possibility that a wire may be connected wrong but i'd bank on the shorted switch or contactor)
also check the switch adjustment, it may have an old style roller arm switch against a detent on the hyd spool, those will get out of adjustment or if they get dirty that can cause problems.
  • Posted 20 Jun 2016 21:41
  • By swoop223
  • joined 23 Mar'12 - 3,691 messages
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
Yes, it was washed recently, apparently I should not have done that because it creates problems :) So I'm guessing it needs to burn off then all will be good. The smoke was sending me for a loop but it seemed to be working properly. Didn't want to burn out the traction motor if the resistor was shorted.

I see on the diagram where the Pump SW should be NO, I'm guessing this is a pressure switch. No idea where it is, perhaps on the pump itself? Perhaps I'm low on hydraulic fluid, though it looked fine. I'm guessing with all cylinders closed I should have the fluid near the top, I don't see anything that suggests a fill level.
  • Posted 20 Jun 2016 10:40
  • By ian_k
  • joined 16 Jun'16 - 6 messages
  • Ab, American Samoa
It is normal for the resistor to get extremely hot when using the truck. If you washed the machine or got any grease on it, it is going to take a little while to burn off and then it should be alright. The switch must be stuck on for the lift pump or the big contactor is stuck and not releasing.
  • Posted 20 Jun 2016 08:45
  • By mrfixit
  • joined 11 Dec'08 - 1,434 messages
  • New York, United States

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