gearbox calculator

[Ether]

Originally Posted by apalrd

For example, say we have a motor (Motor A) which produces 4 units of torque at 5 units speed. Another motor (Motor B) produces 1 unit of torque at 10 units speed. We gear motor B 2:1 relative to motor A such that they are spinning at the same speed when mixed, and the torque output at the mixed point will force motor A to produce 2x the power and torque of motor B, while consuming 2x the current.

That last part -- "while consuming 2x the current" -- is generally not true for different motors.

Generally speaking, if you gear Motor B to produce half as much mechanical power as Motor A at some operating point, it will not be drawing half as much current at that operating point.

Likewise, if you gear Motor B to draw half as much current at some operating point, it will not be producing half as much mechanical power at that operating point.

[apalrd]

Originally Posted by Ether

That last part -- "while consuming 2x the current" -- is generally not true for different motors.

Yes and no.

Assuming the motors were both perfectly efficient (or identical efficiencies), then what I said would be true.

For the CIM and MiniCIM, this is roughly true (the miniCIM will contribute it's share relative to it's power potential), as they are nearly identical motor designs.

[Ether]

Originally Posted by Ether

That last part -- "while consuming 2x the current" -- is generally not true for different motors.

Originally Posted by apalrd

Yes and no.

Assuming the motors were both perfectly efficient (or identical efficiencies), then what I said would be true.

For the CIM and MiniCIM, this is roughly true (the miniCIM will contribute it's share relative to it's power potential), as they are nearly identical motor designs.

For the sake of students who may be reading I need to make a couple observations:

When I wrote "generally not true for different motors" it was not intended to include "nearly identical motor designs". I assumed that would be inferred but perhaps it should have been stated explicitly.

If two different motors have identical efficiencies at the chosen operating point, that would be a special case... not general. In general, the efficiencies of different motors will not be identical for an operating point selected based on current or power.

Your posts are usually very practical. I'm sure you did not expect your readers to infer you were discussing perfectly efficient motors.