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- My system consists of a Power Pack (Motor, Pump, and reservoir as one
unit)
- Two 40 inch hydraulic (two way) cylinders
- One control valve assembly
- Pressure switch
- Accumulator
- Two flow control valves, adjustable flow in one direction, full flow the
other
- Pressure gauge
- External check valve (Power pack has internal one, but for maintenance)
- Return flow filter
- Contactor to run the motor
- This system can also be used to drive a hydraulic motor for azimuth
control
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4
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5
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- The complete hydraulic assembly is on a steel plate which bolts to the
rotating part of
- the dish mount. This is 25’ in the air and has 3 “eye” bolts attached to
allow for lowering
- it for major maintenance if needed.
- I piped the high pressure side of my system with ½” stainless steel pipe
because it was
- available. You will need various adapters, reducers, plugs etc. I advise
using swivel
- connectors wherever you can for ease of assembly and future service.
- All the hoses are locally made to length and are ¼” 5000 PSI rated.
There is no need
- for anything larger as we are more interested in smooth slow operation.
The cost is
- not much more than if ordered pre-made and makes for a much neater
assembly.
- The accumulator is the key item that allows for slow smooth movement.
This also
- minimizes the run time of the pump. During normal tracking of the moon,
I have noted
- that it may be 10 minutes or more between run times for the pump.
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- The accumulator works just like a water tank on a well system. It is
pre-charged to a
- certain pressure with nitrogen (I chose 750 PSI) to operate the
cylinders without
- calling for the pump to energize at every movement request. Your data
may vary due
- to piston size and weight of your antenna system.
- I run the pressure at 1250 PSI max and it drops to about 1000 PSI before
the pump
- starts and charges the accumulator back to 1250 PSI.
- I use two flow control valves metered in one direction and full flow in
the other for two
- reasons. One is the volume of fluid required to extend the cylinder is
more than you need
- to retract it, and secondly, you can control for uneven weight
distribution.
- To my knowledge, I am the only EME station using this particular method
and so far, it
- has been trouble free and works excellent. I do leave power to the pump
on 24/7.
- I do this to maintain constant pressure and assure no air gets into the
loop.
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- The accumulator listed here is NOT the same one I have. Mine is no
- longer available. There are many variations on the web page, and I
- urge you to be sure that the one you order has the right capacity to
- handle your project. Mine is approximately 2 quarts. I do not have
- a good working knowledge, but I have been advised that one does
- not need a large volume accumulator to be functional. The main
- function is to maintain a relatively constant pressure and to absorb
- abrupt changes when the valves are actuated.
- Also, you do not need to purchase a “Power Pack”. You can assemble
- your own pump, motor, and reservoir to suit your needs. The one I
- have is set to bypass at 2000 PSI.
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- The following parts can be found at www.SurplusCenter.com
- Main control valve with 24 VDC solenoids 9-5679
- Two plugs needed 9-6408-12
- Flow control valves 2 ea
9-5300-25
- Check valve is your choice 9-1019-50
- Pressure gauge 21-1246-J
- Filter is your choice (I use a fuel flow filter)
- Hydraulic cylinder of your choice (I bought mine new to avoid leaks)
- These parts can be found at MSC www1.MSCDirect.com
- Pressure switch 56491152
- Accumulator 76133990 or similar.
(See things to consider)
- This can be ordered at www.northerntool.com
- Power Pack 1530036
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Notes
