Hmmm... thought I put up a post yesterday (even got a response notice in my e-mail) but it is gone today... Anyway....

It is awesome to be able to talk with experts!!!!!

In my sketch of a new hydraulic system, I put in what I called an "unloader" valve. It would be a normally open valve just after the pump ( along with a relieve valve ), that would let the motor start with no load. After the pump runs for a few seconds, I would close it and energize the system. I did this because we design air compressors in the same way ( worked for a custom air/vacuum shop as head designer for 5 years).

I found it odd that I did not see such a circuit on the forklift. I did not imagine that having the switch make just before opening the spool valve would accomplish the same thing. Thanks for the insight!!!

As for speed control, I faced this problem when I worked for Westinghouse (about 10 or 15 years ago). We had a custom built lift to stand the "bundles" from horizontal to vertical. Then the ram reached the top of the lift and the solenoid valve shut, the "jerk" caused the bundle to move around a bit (lift unit was 20 ft long). This cause no problems but it was pointed out that our customers did not like to see there units being "bounded around".

To solve this I installed a proportional flow valve in line connected to PLC. At the beginning of the lift, I simply ramped up the valve from 4 to 20 mA over a few seconds. When I was nearing the top of the lift ( had a proximity switch sense this), I reversed the action, slowing the unit down till it gently came to a stop and "locked in".

I would like to do the same thing here. Automation Direct has some reasonable priced PLC's. My big expense I think will be the proportional flow valve.

I did think about three parallel solenoid valves each with a flow control valve. I could have all three open untill just at the top. I would then shut down one then a second. This would "step" the unit to a slower speed. I think though that by the time I buy three solenoid valves, three control valve and switches, I will be up to the same price as a proportional valve.

As I said the model # of my machine is 20R30TN

The serial # is 020-82-21354

Thanks so much !!!!!!!!!!!!!!!!!!!!

Mike