# One compliation of Motor Curves

Is there one compilation of motor curves in existence yet, if so, wanna start one using this thread?

Post all motor curves you have for the 2009 motors.

Here are the motors from previous years… I am still missing one… the Mabuchi RS385SH-2270.

2009 Motors1.xls (95.5 KB)

2009 Motors1.xls (95.5 KB)

So I found a spec sheet on the RS-385SH. But the specs are rated at 20V.
Can I expect the performance at 12V to be approximately 12/20 or 3/5 the performance at 20V?
If so will this relationship hold for all specs that I am interested in such as free speed/current and stall torque/current?

Here is the spec sheet:
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_385sh

Yes, the 12V speed vs. torque performance will essentially be 3/5 of the value at 20V. You can just translate the speed curve (the “N”-line) downward parallel to the existing one on the graph.

The current response is a different story, since current is proportional to torque (speed being proportional to the input voltage). The current draw would follow the same curve (the “I”-line) as shown, but the maximum current (stall current) would be scaled back to the point where the speed curve crosses the x-axis (at zero speed).

This would make more sense if you extrapolated the curves shown on the graph to the 65.7 milli-Newton-meter stall torque and the 6.20 A stall current that the motor is rated for. Then, redraw the de-rated speed curve and a vertical line drawn at the stall point would provide the new expected stall current. In simpler terms, as long as the motor is still rotating, the current draw for a given torque would remain essentially the same regardless of speed.

Hope this helps, without being too confusing !