Bush65 Posted March 7, 2006 Share Posted March 7, 2006 There are numerous ways of controlling variable volume pumps. What Fridge described sounds to me like what is known as a compensator control. These work reasonably well. An good way to achieve excellent manual control over the compensator is to pilot operate the compensator with a sequence valve. Then use a manual valve to control the flow out of the the vent port of the sequence valve. On another matter, winches need some way to control the maximum rope load. Electric motors do this by letting the smoke escape. Some PTO winches have shear pins. These are the pits IMHO. Others may have clutches, but I have reservations about them. Hydraulics have pressure relief valves. IMHO, this is a big advantage. Quote Link to comment Share on other sites More sharing options...
Tobias Posted March 7, 2006 Share Posted March 7, 2006 I believ variable displacement pumps of he type discussed are prohibitively expensive. At least those I've found. e.g. a normal pump with magnetic coupling do be driven by belt from crank is about SEK4000 (£290-ish) A variable displacement is about SEK15-20000 (£1000-1300-ish) A two speed, like used for log splitters to get high no load speed for piston return and high power-low speed for splitting should work better in a drive-assist situation. They are almost twice as long as a normal and 50-70% mor expensive. A set of pressure val´ves switches automatically between highpressurelowvolume and lowpressurehighvolume pump stages. Tobias Quote Link to comment Share on other sites More sharing options...
dollythelw Posted March 7, 2006 Share Posted March 7, 2006 I dont know about you John but I find a pressure guage gives me all the feedback I need, if its banging into the PRV zone then I dont have to waste time hoping to pull out, just re-rig and get on with it, saves on rope stress too B) Simon - if memory serves an MR2 is 9cc/rev, if you want more then use a tipper truck power pack, ripped from the commercial breakers just outside of southampton Variable pumps and high pressures arent the best of friends, the system we run is set to pressure releive at 200bar, have a look at the pumps flowing 60+ litres at 1400rpm - they tail off at 100-150bar, also take into consideration the required torque to drive it - a landy diesel wont deliver that amount of torque without climbing the rev range and you loose the wheel matching you are looking for, if wheel match is your bag then a tandem pump pto mounted will do your job Sorry Andy - post wandering off subject Tobias - good to see you here!! Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted March 7, 2006 Share Posted March 7, 2006 I've got a tail lift pump off a 7.5 ton truck that i'm going to use as back up. Quote Link to comment Share on other sites More sharing options...
kkk2 Posted March 7, 2006 Share Posted March 7, 2006 We are using a Salami 2BP22.5-P28P1 Hydraulic pump, Cannot get the numbers from the motor, the electric clutch is a Collagere Clutch Pak, The Winch is a Ramsey 8000 hydro, Line speed is not known, but while not as fast as an 8274, it is faster than the Eastern electric winches, We need 11mm Plasma minimum on it, We run the relief valve at 2200psi and have only stalled the motor once. The set up will run all day every day, the oil tank holds approx 35 ltrs with a filter on the return, The set up is off an utility company truck, The air con pulley from landrover fitted to the crankshaft gives it power, we run a kevlar belt to drive the motor, whole kit cost 600.00 euro second hand. We have a hand trottle to vary the speed, and as it has an electric clutch we have fitted an emergency stop which makes operating it very safe. Two weeks ago we were breaking 9 to 12 inch diameter butts of trees, it could shear the trunks with no hassle. We also run a M8000 on the rear with an 6.5 hp warn motor just in case. I have some photos, I do not know how to put them up though Quote Link to comment Share on other sites More sharing options...
Hillbilly Raider Posted March 7, 2006 Share Posted March 7, 2006 We are using a Salami 2BP22.5-P28P1 Hydraulic pump, Cannot get the numbers from the motor, the electric clutch is a Collagere Clutch Pak, The Winch is a Ramsey 8000 hydro, Line speed is not known, but while not as fast as an 8274, it is faster than the Eastern electric winches, We need 11mm Plasma minimum on it, We run the relief valve at 2200psi and have only stalled the motor once. The set up will run all day every day, the oil tank holds approx 35 ltrs with a filter on the return, The set up is off an utility company truck, The air con pulley from landrover fitted to the crankshaft gives it power, we run a kevlar belt to drive the motor, whole kit cost 600.00 euro second hand. We have a hand trottle to vary the speed, and as it has an electric clutch we have fitted an emergency stop which makes operating it very safe. Two weeks ago we were breaking 9 to 12 inch diameter butts of trees, it could shear the trunks with no hassle.We also run a M8000 on the rear with an 6.5 hp warn motor just in case. I have some photos, I do not know how to put them up though Hey Kev less winches more HILLBILLIES! (private joke guys) MANDY. Quote Link to comment Share on other sites More sharing options...
nas90 Posted March 7, 2006 Share Posted March 7, 2006 Big Si said: The main problem with both hydraulic & PTO is getting a line speed at which you can assist with a bit of drive to the wheels. You may say that they are just so powerful that there is no need - but I beg to differ - you'll probably just snap the line. Imagine climbing a step - the winch pulls you in to the step, not over it. Apply a bit of drive and the wheels will climb the step. With the NAS being auto, with lockers both ends and using a Milemarker I can assist the winch when solo recovering with careful use of throttle and gear selection. I cannot think of a situation when I was overloading the cable or recovery was difficult. Maybe (before GB MUD gets there) my usually sedate pace of driving suits the Milemarker line speed and the NAS gearing? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 8, 2006 Share Posted March 8, 2006 An auto would be ideal for drive assist for me too, I just don't want an auto off road the rest of the time (don't like them off road) Quote Link to comment Share on other sites More sharing options...
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