re:acceleration, was:Re: Another router video..

Mariss,
It would be interesting to know how much power the stepper motor can supply.
Given your numbers below, if more weight were added to the stage to slow
down the acceleration and the same values measured, the motor power should
be easily determined. This would be assuming that the motor is producing
the same amount of power with each of the two load masses. Maybe it would
be better to measure the times with more than two different loads.

High speed video is expensive, maybe an LED on the stage could be made to
flash at 1 kHz or so and a single image with a still camera. If you pan the
camera perpendicularly to the stage motion for several cycles of motion, it
might make a really pretty picture.

The "parallemic triaglide" type stages
http://www.parallemic.org/Reviews/Review002.html have been claimed to have
up to 50 g acceleration. If this could be maintained for 17 seconds, it
could be used to hurl something into orbit.

17 seconds * 50 g * 32 ft/s^2 *3600/5280 (seconds/hr)/(ft/mile) = 18545
miles/hour.

regards-
Elliot



Date: Fri Jun 2, 2006 1:57 pm (PDT)
From: "Mariss Freimanis" mariss92705@...
Subject: acceleration, was:Re: Another router video..


Well, I jacked it up a little:

Velocity: 65.535" per second or 1.664 meters per second
Motor speed: 3,932 RPM
Accel time: 0.0853 seconds
Accel rate: 2 G
Distance moved: 20.000" or 0.508 meters
Move time: 0.392 seconds
Avg velocity: 51.02" per second or 1.296 meters per second
Avg motor speed: 3,061 RPM
Out and back time: 0.784 seconds

This will be a very short video.:-)

Mariss


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Elliot Burke" <elliot@...>
wrote:

>
> Marliss,
> Just for fun I ran these numbers on your motor:
> top speed 50 inches/second
> travel 24 inches
> time 0.5 second
> Assuming constant acceleration up to 50 inches/second, then

constant speed

> after that, two equations can be written:
> 1/2 a t^2 + 50(1/2-t) = 24 and a t = 50.
>
> Solving these simultaneously gives a = 1250 inches/second^2 and t

= .04

> second.
> 1250 inches/second^2 is about 3 g. So the motor accelerates for 40

ms at 3

> g and then coasts at constant speed for the remaining 460 ms.
>
> If the size of the screw and the mass of the stage it was moving

were known,

> it would be easy to calculate how much power was being applied by

the motor.

> This would say something about the efficiency of the drive if the

input

> power were known.
>
> If you kept the acceleration constant at 1250 inches/second^2, the

stage

> would travel the 24" in 200 ms, reaching a velocity of 245

inches/second or

> 14700 inches/minute.
>
> regards-
> Elliot
>

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