NXT motor parameters

[hippicurean]

Hi all,

I came across Philippe Hurbain's excellent website sometime ago. On the Motor Internals page, there is a link that points to Ryo Watanabe's page containing information on NXT motor parameters. On that page, the torque constant (Kt) and back-EMF constant (Kb) have rather different values. In theory, they are supposed to be numerically identical when using SI units. Naturally, some level of empirical error is expected when data is obtained experimentally. However, the discrepancy between the two values is large enough for one to question the validity of the data used for deriving the motor constants.

http://www.philohome.com/nxtmotor/nxtmotor.htm
http://web.mac.com/ryo_watanabe/iWeb/Ry ... Motor.html

I've emailed Prof Watanabe a couple of times already without getting a reply. Could anyone shed some light on this, please? Thanks.

Cheers
Hippie