Torque or horsepower needed for 3 phase gearmotor, brake, VFD
Iíve built a light weight frame for a hoist which only needs to lift around 500 lbs. The cable spool needs to hold 250í of 3/16 cable that can lift a submersible pump from that depth. The hoist will also be used to develop the well and without going into great detail about this, Iíll just say I need the spool to be variable speed with a holding brake with the RPMS from 0-100. I could do all this with hydraulics which I know more about but I would like to explore the idea of a 3 phase gear motor with a constant brake, reduction to 20:1 gear box and a variable frequency drive. I need help in knowing what minimal horsepower motor Iím looking for and what type of brake would be sufficient to hold the load. Also, I need an adequate VFD converter from 1 phase 115 v to 3 phase 208-230 with some kind speed control by a foot pedal if possible to keep my hands free. Some VFDís canít be used above 3,000í altitude and Iíll be using this at 7,200í ( a Nema 4 enclosure maybe appropriate because Iíll be using it outside). And to top all this off, I need the motor, gearbox and VFD combined to weigh 40 lbs. or less. Now if there is a simpler way to do this, like a brushless motor with speed control or something, let me know. It needs to be 115 volt system with constant torque with the ability to hold the cable.