Gear speed multiplier for pump
Gear speed multiplier for pump
(OP)
I have an unusual situation where I am trying to run a pump manually with a mechanical device that is very slow (40 RPM max) but high torque (1500 in-lbs), while the pump should be run closer to 1500 RPM and 100 in-lbs torque.
Most gearheads seem to be made to reduce high speed motors, while I'm looking for the opposite (convert manual crank to motor speeds). Is this as simple as turning a gear speed reducer around the other way? Any advice where I can find what I'm looking for?
Most gearheads seem to be made to reduce high speed motors, while I'm looking for the opposite (convert manual crank to motor speeds). Is this as simple as turning a gear speed reducer around the other way? Any advice where I can find what I'm looking for?





RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
My crank input power, P = 125 (ft-lbs) * 40 (RPM) / 5252 = 0.95 HP
0.95 HP >> 1/3 HP
What am I missing?
RE: Gear speed multiplier for pump
Kyle
RE: Gear speed multiplier for pump
first info [1500 rpm * 100 in.lb (output)] > [ 40 RPM * 1500 in.lb (input)] which is not possible
1500 / 40 is a 37.5x speed increase, which seems a lot to me. A quick internet search didn't turn up anything higher than about 7x speed increaser, and those are way too big for your application.
Perhaps you would have better luck using a small DC generator and DC motor to accomplish the speed change? You could also look at a generator + battery + PWM controller if you need variable output speed/power.
RE: Gear speed multiplier for pump
The next problem is the 22.5:1 Output to input ratio. That's a pretty large jump in ratio; maybe 3 stage spur gear or two stage planetary. It might be cheaper to get a motor that is matched to the load; likely to be more reliable.
RE: Gear speed multiplier for pump
What does this mean??
ivymike - you typed faster than I did.
RE: Gear speed multiplier for pump
For the given pressure and flow, your pump needs 0.333HP
You want more flow, so the pump has to turn faster. Increasing the speed leads to a lower torque, but the extra flow generates extra pressure and pressure x flow means more power...which needs more torque.
You need to work out how much power you need, as a function of the required pressure and flow.
Add in the efficiency losses.
That will tell you the total power you need.
HPost CEng MIMechE
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
"A trained cyclist can produce about 400 watts of mechanical power for an hour or more, but adults of good average fitness average between 50 and 150 watts for an hour of vigorous exercise. A healthy well-fed laborer over the course of an 8-hour day can sustain an average output of about 75 watts.[1] The yield of electric power is decreased by the efficiency of the human-powered generator." Wikipedia: Human Power
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
What?
So you intend:
Power source --> Motor of robot --> Mechanical, hydraulic, pneumatic or whatever linkage --> Robot "arm" --> Crank handle --> Speed increasing gear train --> Pump
Don't you think that it would be more efficient to do:
Power source --> Jumper cables from the auto part store --> Motor --> Pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
Did I mention I think it's a bad idea?
Have you considered hydraulic quick-connects?
Have you considered multi-jaw couplings with a guided/compliant shaft, starting at ~zero speed while coupling and at pump speed while coupled?
Have you considered an eddy-current or other magnetic coupling?
Have you considered a flat plate friction coupling?
Mike Halloran
Pembroke Pines, FL, USA
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
http://www.winsmith.com/documents/D90-TYPE_SE_Cata...
RE: Gear speed multiplier for pump
http://www.icrepq.com/icrepq-08/398-jaliu.pdf
or try the baldor catalog
http://www.baldor.com/support/Literature/Load.ashx...
RE: Gear speed multiplier for pump
RE: Gear speed multiplier for pump
Use a larger pump that will deliver the flow you need at 40rpm speed.
Ted