Re: reality check...

Eire,

Your Kt is 37.51 in-oz. Kv is always Kt/1.351 so your Kv is 27.76V /
1,000 RPM. The max continuous current is 8.9A and the terminal
resistance about 1 Ohm. The max voltage is 60VDC; the effective motor
voltage is 60V - (8.9A times 1 Ohm) or 51.1V

1) This gives you (51.1 / 27.76) times 1,000 RPM or 1,841 RPM.
2) 8.9A times 37.51 in-oz / A gives 334 in-oz of continuous torque.

From (1) and (2), The power output is 1841 * 334 / 1351 or 455W

Another identity is Watts = IPM * Lbs / 531. Solving for Lbs gives:

Lbs = Watts * 531 / IPM. Plugging your numbers in gives:

455 Watts * 531 / 500 IPM = 483 Lbs of Push.

Your pinion circumference is 3.926", at 500 IPM its RPM is 127 RPM.
Meanwhile the motor is turning 1,841 RPM. That means a motor to
pinion reduction ratio of 1841 / 127, or 14.5:1 to get what you want.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Erie Patsellis"
<signworks@c...> wrote:

> OK, given the following:
> Application: Rack & Pinion Gantry router, work area is 8' x 13'
>
> Motor Specs:
>
> 37.51 oz-in/A (Kt)
> 25.0 - 30.5 V/kRPM (Kv)
> Terminal resistance 0.75 - 1.02 Ohms @ 4A
> Max terminal voltage 60V
> Max continuous speed 2100RPM
> Max peak torque 1500 oz-in
> Max peak current 44.5A (unsure)
> Max continuous stall torque at maximum motor temp 300oz-in
> Max continuous current 8.9A
>
> Reduction Calulations:
>
> a 40:1 drive reduction with 24 d.p. rack, 30t 24 d.p. pinion

(effective

> circumfrence of 3.926 inches)
>
> desired rapid of 400-500 ipm (approx 100-125 rpm pinion speed)
>
> I calculate I would need a 2.38:1 ratio from motor to reduction

unit, does

> this ((125*40)/2100=2.380)
> will give me a torque at 20 amps(gecko 340 max current) of
> (37.51*20)/2.38*40=12,608 in oz)or 788 in lbs of force.
> >anybody remember how to calculate force at the tool with a rack &

pinion

> drive?
>
> 1024 count quadrature encoders * 4= 4096 counts per rev, 2100

rpm=35 rps,

> 35*4096=143,360 pulse frequency, in excess of
> mach 2's limit of 45 Khz, I'll have to use a pulse multiplier of

either

> x5(28672 khz) or x10(14336 khz).
>
> If I go with x5, I end up with about 3500 steps per inch, x 10 is

around

> 1750 steps per inch.
>
> any problems with my math???? suggestions as to which way to go

(x5, x10)

>
>
>
> Erie Patsellis
> Shelbyville Design & signworks
> 217-774-4444
> signworks@c... <mailto:signworks@c...>
>
> <mailto:signworks@cond>
>
> Visit our website at: http://www.shelbyvilledesign.com