As mentioned previously, the electric actuator wasn't up to the task of moving the array. The neccessary parts for a small hydraulic system can be had from surpluscenter for not much more than a larger electric actuator would have cost. And since there's very little slop in a hydraulic system and it's certainly plenty strong, we decided to go that route. The white cylinder is actually a large oil filter. The original intention was to use the filter as a tank (hence the large size), as recommended by a local hydraulic guy.
Here it is with the cover removed. Using the filter as a tank didn't seem to work out very well... I could never get all the air out of it. When used as a tank, the oil level needs to rise up and down as the cylinder expands and contracts. It turns out need a bit of pressure to pull the oil through the filter element - gravity just won't do the trick, so the center of the filter was constantly being sucked too low and the outside overflowing. I ended up welding a small tank and screwing it to the top of the filter to keep it always full of oil. The pump is a small volume gear pump, and the pressure regulator is set to around 1000 psi. The blue rectangle in the righthand side is the double-acting solenoid. It's driven by two 115 VAC solenoids. Powering one drives the ram in while powering the other drives it out. On the outlet of the solenoid is a needlevalve to adjust the speed of the ram. The goal here is slow movement, so it's tightened down a lot. As a side note, some of these have one way valves allowing free flow in one direction, so they work much better installed the right way. :-)
This is the ram installed. It's a 20" stroke x 2" bore. The wires tied to it there are running to the limit switches. This allows the controller to determine when the array has reached the extent of it's travel.
Another shot of they hydraulic system. The two junction boxes sitting there house relays to control the motor and solenoids. The white wire runs down to the controller and is connected to the coils of these relays.
Here's the controller mounted at the base of the mast. Just a modified Square-D disconnect box. That's enough for here, so more about that on the next page...