Fisher Price Motors

[GramNegative]

I have a question about calculating the max power of the Fisher-price motor. I made a spreadsheet to redo the motor data from the "Tips, Guidelines and Good Practices" chart so that all of the units were consistent (Nm for torque and rad/s for speed).

I keep getting calculations that are not even close to the information provided and when I went to do it by hand I encounter the same problem. So, for example, I was fairly certain that the fisher price max power should be attained like this:

max power = (torque at stall divided by two) times (free speed divided by two)

Pmax = (T0/2)*(Wf/2)

T0 = 417.7 mNm * (.001) = .4177 Nm
Wf = (15636 RPM * 2 * pi)/60 = 1637 rad/s

Pmax = (.4177/2)*(1637/2) = 171W, as compared to 387W published

Which is so off that I've rechecked my work multiple times but cannot find any error.

Also, regarding the octagonal drive adapters for the FP gearboxes (mentioned by George), where are those available for purchase?