[Atlas_Too]

Hi,

I have a couple of brushed DC motors I'm interested in using but I'm having problems finding what kind of current they will handle. They have the following ratings:

Voltage: 90
RPM: 1400
in-oz: 400

Knowing the torque is it possible to estimate or calculate the current draw?
If I can't calculate this what would be the best way to measure the current with out damaging the motor?

Thanks for any advice,
Dan

[Al_The_Man]

Attach an arm or fit a large dia pulley to the shaft.
Wind or attach a cord to arm/pulley and using an accurate as possible spring scale, attached to the cord, gradually apply a DC voltage into the armature using an ammeter in series, or clamp on type.
The idea is for the spring scale to be applied to resist the turning effort of the shaft, the direct reading of torque constant can be obtained (Kt=Torque/amp).
IOW, the radius of the arm/pulley and scale reading will give you the oz-in/amp.
You can then extrapolate what current will give you 400oz-in.
Al.
,