If I was looking at doing this hydraulically, I would use the common practice of using one hydraulic 2-coil valve In-out function with centre off , this has two benefits of switching the hyd pump off between stroke operations and centre hyd lock of the solenoid cylinder.

 

If I was looking at doing this hydraulically, I would use the common practice of using one hydraulic 2-coil valve In-out function with centre off , this has two benefits of switching the hyd pump off between stroke operations and centre hyd lock of the solenoid cylinder.

MAX has repeated what I have said in posts #16, #18, and #20. He added a bit more explanation, so THANKS, MAX!! I have designed systems that have included a lot of hydraulic controls, but evidently my suggestion was too confusing.

 

This project has changed from electro-mechanical antenna slewing to hydraulics. I wonder why. Is the antenna too big and heavy for the screw jack? It was originally designed with a screw jack, and is that no longer sufficient? Has something failed?

[edit]
Don't know where I got the idea this was an antenna such as a dish. In post #8 you mentioned moving something North or South. I just assumed it was a dish and the north/south tracking had to do with satellite tracking. I'm probably wrong.
[end edit]

 

This project has changed from electro-mechanical antenna slewing to hydraulics. I wonder why. Is the antenna too big and heavy for the screw jack? It was originally designed with a screw jack, and is that no longer sufficient? Has something failed?

[edit]
Don't know where I got the idea this was an antenna such as a dish. In post #8 you mentioned moving something North or South. I just assumed it was a dish and the north/south tracking had to do with satellite tracking. I'm probably wrong.
[end edit]

In post #1 it clearly states "I have a solar tracker." and then adds that presently it is a motor drive. We have no hint about the reasoning for wanting the change. There may be a motor-starting-under-full-load problem, or possibly the motor is just undersized for the application. One consideration that has not been addressed is that hydraulic systems require a pump delivering pressure and flow capability before they can do anything, and that means that the pump must already be running prior to any move. But maybe the TS already has an operating hydraulic system with enough spare capacity to provide the motion.
The really bad news is that probably a hydraulic system for this application will be quite a bit less efficient.

 

Yeah, MisterBill2 I agree.

I assumed it was a dish, but it could be solar panels as well. Maybe - and it would be nice if Mikhail2023 would address clearly what it is he's working with. I'm also wondering if maybe - IF it's a solar panel, perhaps a heavy snow load could be the reason for wanting to upgrade to a more powerful system for tracking. But then if it is a solar panel covered with snow then tracking a sun it can't see would seem superfluous.

 

Post #1 was rather specific, except for not mentioning the size or weight of the array. While the less expensive motor driven linear actuators will tend to wear out, the common failure mode in double acting hydraulic cylinders is a loss of efficiency due to internal leakage. But the device will continue functioning. When a leadscrew reaches some advanced state of wear, the failure is total.
And the bad news is that normally a hydraulic motion system must have a hydraulic pump to make things move. So there is that pump efficiency getting into the picture. Hydraulics can be very powerful, but not more efficient, USUALLY.