Quote:
Originally Posted by pilleya
For teams wanting to do this or something similiar, make sure you only use the low-power RS775-125 that Andymark sells. If you try to hook up a 775pro or 775-18 it is not going to end well for you. Andymark says on their website that if the pg27 with a 9015 is stalled then the gearbox will break. So even a reduction as low as probably 10-15ish:1 with a decent 775 will cause failure of the gearbox. In comparison the Versa-Planetary is rated up to 210:1 for the 775pro. So the gearbox can only handle 1/20th of the torque.
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Check
that again:
Quote:
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Originally Posted by PG27 web page on AndyMark
Performance Specs:
- Gearbox Reduction: 26.9:1
- Voltage: 12 volt DC
- Dyno Tested No Load Free Speed: 512.4 rpm
- No Load Current: 1.2 amps
- Gearbox Output Power: XX Watts
- Dyno Tested Stall Torque: 3.55 ft-lbf
- Stall Current: 63 amps
- Minimum torque needed to back drive a non-powered PG27: 0.3ft-lbs
- Maximum torque applied at shaft which breaks gearbox: 39 ft-lbs (breakage point is shearing of shaft)
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There's another factor of ten in torque before breakage. Using the PG-188 with a higher torque motor is certainly subject to a sheared shaft, as stall torque with the 9015 motor is listed as 33 ft-lb, on the same output shaft.