Re: [CAD_CAM_EDM_DRO] Bridgeport Boss 6 Stepper Motors

vavaroutsos wrote:

> Does anyone know what the model number of the stepper motor that was
> used on the Series I Bridgeport with Boss 6 control? The ones from my
> machine are already gone. I know they were made by Superior Electric,
> but nobody at Bridgeport or Superior knows what was used.
>
> I would like to find the specs so I can get a better idea of the
> force that Bridgeport provided on each axis. This will help me in
> sizing some new servo motors.

Note that servo and stepper motors have such different performance, that
a direct comparison is not correct. Steppers have a severe falloff in
torque as the speed increases. Servos generally provide full torque
up to the maximum speed that can be achieved with a perticular power
supply voltage. Servos also have the capability to provide peak torque
that is above the continuous rated torque for some short time.

So, if 1600 In-Oz motors stepper were used, a 400 in-Oz continuous
rated servo motor would likely do. Also, if the steppers were direct drive,
you could use a 100 Oz (cont) servo with a 4:1 belt reduction ratio, as
the servo generally has no trouble spinning at several thousand RPM.

What you might want to do is define the highest feedrate and rapid traverse
speeds you will want to run at, and the leadscrew pitch, and do some
elementary calculations to determine the motor needed to reach that
performance. (I'm using 1/8 Hp (cont) servo motors on my Bridgeport,
and I can deliver 1000 Lbs linear force to the table, which seems to be
enough to bust things pretty good!) See http://206.19.206.56/motor.htm
for how I calculated this.

Jon