Electrical Engineering Asked on December 15, 2021
I have a skid steer loader that in ISO eg driving straight forward with one joystick supplies on average 50 milliamps more power to the right forward solenoid coil than to the left coil causing the machine to steer to the left dramatically, the dealer has swapped out the computer and joystick control pods with no effect, I have hot wired the wiring loom to eliminate that as a problem and no luck, the dealer has abandoned the job, I have taken the machine to a rexroth specialist who tells me there is nothing wrong with the hydraulics and the problem is the electronics, so back to my original question is there such a thing that can be installed between the computer and the coil that can take input of say 500 milliamps and output 550 all the way up to 1.100 milliamps and output 1.140 or can the power to the other coil be reduced by 50 milliamps to achieve the same outcome? Bobcat Skid Steers have software to eliminate this problem however Case skid steers dont I would be grateful for any help or suggestions
The wheel motors start to turn at 560mA and as you push the joystick forward it increases the current gradually through to full speed at 1160mA.
The reason i have put this question up is that i am a skid steer operator who can wire up a light but i have no idea about electronics, so if I were to fit a resistor in series with the solenoid coil would that work through the range from 560-1160 so instead of 560mA it would be 510mA and at 850mA it would be 800mA?
Skid steer machines have one drive motor on each side of the machine, one drive motor is connected by chain to both wheels on the left of the machine and the other drive motor drives the wheels on the right side of the machine.
There are two operating standards
ISO uses one joystick to drive both wheel motors and
H Pattern uses the left Joystick to operate the left side wheels and the right joystick to operate the right side wheels,
the machine works perfectly in reverse and I have swapped the coils around to assess if the coil could be an issue but it does not appear to be,
A youtube video of what is happening is here
Despite other comments re the problem being mechanical I think it looks electrical.
Your video showing the two meters with different readings seems conclusive IF that happens while pushing the joystick 'up the centre'.
If your dealer sees that happen how do they explain it? - or rather how do they not see it as a clear electrical error?
There is something in the joystick control circuitry that produces an imbalance in current. Either the joystick pots are faulty or the electronics that convert pot value to current or the load (solenoid) and/or its power supply.
The dealer MUST be able to make the system produce balanced current or there are problems with their competence.
Answered by Russell McMahon on December 15, 2021
Measure both coil resistances. And the joystick voltage. With that known it may be possible to work out how to trim out the error.
Based on your current question it sounds like a 50mA constant current sink could be a quick and dirty solution. However i am left suspecting its a voltage driven joystick. And the resistance is lower on 1 coil
Having measured both coils if you find there is a difference. Then adding series resistance to match it back up may resolve your issue. Otherwise with that information it may be possible to design a solution.
Answered by Reroute on December 15, 2021
Get help from others!
Recent Questions
Recent Answers
© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP