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Unread 02-01-2005, 14:21
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Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
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Re: White Paper Discuss: Nothing But Dewalts

Quote:
Originally Posted by Joe P
STU,
We just got a prototype chassis running with the CIM Dewalts. We haven't had time to think about this yet. Maybe someone on Team 47 has done some work on this, I don't know?
This is a thing easily done. The planetary gearboxes should be pretty close to the "published" efficiencies of 85-90% for each planetary stage (with these low ratios per stage -- higher ratios like 10:1 in one stage can be VERY inefficient).

This would mean that in 2nd & 3rd, the gearbox should be 70-80% effecient and in 1st, the gearbox should be 60-70% efficient.

Note well that effeciencies apply to TORQUE not speed. The speeds are simply divided by the ratio while the torques are multiplied by the (ratio X eff).

Given this data, it is a simple matter to go into DrJoesMotorCalc spreadsheet and get any speed-torque curve your heart desires.

Joe J.
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