Re: Servo Motor's I have 27 @400oz

Hi,

This is what you can do to figure out what you have if you don't have
the motor specs (stall torque, velocity constant, torque constant and
peak power)or want to verify them:

1) Accurately measure the motor armature resistance. Chuck the motor
up in a drill press. Measure the motor's open circuit voltage. Then
set your multimeter to DC amps and measure the motor short circuit
current. Divide the voltage by the current to get the armature
resistance R.

2) Use the following equation to calculate the motor's peak power in
Watts: W = V squared / 4 * R Where V is the motor's rated voltage,
(say 24VDC).

3) If you accurately know your drill press RPM, you can also
calculate the motor's velocity constant (Kv). Measure the motor
voltage as in (1). Divide the measured voltage by your drill press
RPM and multiply the result by 1,000. That is the motor's velocity
constant Kv (volts per thousand RPM).

4) Calculate the motor's no-load RPM. Multiply the drill press RPM by
the motor's rated voltage, then divide the result by the motor
voltage measured in (3).

5) Calculate stall torque (oz-in): Torque = Watts * 1351 / no-load RPM

6) Calculate Kt: (oz-in/amp) = T(stall) * R / V(rated)

Thats all there is to it!

Mariss

--- In CAD_CAM_EDM_DRO@y..., marble_h@y... wrote:
> hi group I just got a shipment of 27 servo motors rated at 400OZ
I
> will give more info on them on Monday I will be selling most of
them
> any takers contact me off group .Some have both tack's and
encoders
> and others have just one or the other . Not sure on the price
should
> be around $125.00 CDN