!
186,000 miles per second.
It is not just a good idea, it is the law.
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rafael Skodlar
Sent: Tuesday, July 22, 2008 1:49 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] CNC design questions
Thanks
Rafael,
This is an idea on how to provide linear motion to a single axis:
http://www.oemdynamics.com/hld_animation/hld_intro.html
The Harmonic Linear Drive (HLD) article was posted in Machine Design on
6/16/08:
tool motion: 120 x 90 x 20 cm (X-Y-Z)
Posibly a little small. Remember it doesn't cost much more to go bigger.
It does depend raher on what you want to make.
frame material: T-slotted aluminum
Easy to work with though quite expensive if you can't get it second
hand. Remember
Numbers you quote here are better than what I'm hoping to achieve even
though I'll try to come as close as possible. .05 mm repeatability on
1m run is probably hard to achieve with stepper motors without
positional feedback. It woild be interesting to know what others were
able to do with
Regarding power supplies:
Computers use regulated power supplies because the electronics require a
voltage within a relatively narrow range. You don't need a regulated
supply to drive a stepper or servo (although you might for some of the
electronics connected to them). For that reason, the
Steppers do not consume more electrical power during rapid accel. The
biggest draw is when sitting still between the time you stop sending
pulses to the drive and the time it switches to reduced idle current, if
it has that ability.
Once you size the power supply to the full load demands of the
Sorry Ray but you are wrong. You have maximum current at low speed and
stationary but maximum power is at high speed (technically it peaks at
the corner frequency) and maximum acceleration. Like any motor, power
out = power in - losses. Look at fig.14 in the step motor basics and you
will see
I guess we must be looking at or thinking about different things.
Perhaps I did not say it well. The DRAW on the power supply is what I'm
saying is greatest at zero speed. After all the comment in the earlier
post was that the DRAW on the power supply would be greater during
acceleration. That
With a switching drive such as a Gecko the current through the motor is
regulated by adjusting the output voltage. Below the corner frequency
the current is fixed. Above the corner frequency the drive can no longer
supply enough voltage to overcome the inductance of the motor so the
current
Nice discourse on current between stepper drives and stepper motors and
some of the theory of switching drives. I'm still left with the
statement made earlier in this thread by Rafael Skodlar,
The reason I mentioned power supply is I'm not sure which way
to go, linear or
Well, you have lots more homework to do... For the gecko drives you only need a
breakout board like a C11 (I think) from CNC4PC. I prefer automationdirect
steppers as they are cost effective. Keep in mind the larger the steppers the
slower
they go. Looks like you have got a firm bite on the
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