Re: Xylotex / RapidSyn/ Power Supply help?

Message: 6
Date: Sat, 14 Dec 2002 02:41:58 -0000
From: "turbulatordude <davemucha@...>" <davemucha@...>
Subject: Re: Xylotex / RapidSyn/ Power Supply help?

Hi Volitan,

Just a little off.

The stepper is current limited in as much as the coils can only take
so many amps.

the power is injected into the coil to inject amps. the higher the
voltage the faster the coils are energized.

higher voltage = faster response.

you do not limit the current. the driver monitors the current and
chops it when the current is reached. you do set that limit in the
driver when you set it up. not sure how in the Xylex, but in the
Gecko, you do it with a set resistor. Check your manual.

I would bet that we will find our soon enough how to set that range.

The stepper nameplate is NOT the running voltage, but the voltage
with which you do your calculation. it is just a set of base values
for calculations. I am not sure how the industry picked the low
voltage ranges, but typically you drive the stepper from between 5
and 25 times the nameplate voltage. you never over amp.

Check the motor manufacturers site. I would bet that they show
performance data on 24 volts and nothing near as low as the nameplate
voltage.

Dave

[What about servos? The servo motors I've been looking at list voltages
which range between 12 and 60 VDC. (See
http://www.polysci.com/Documents/moc23series.PDF ) I'd been assuming that
this referred to the running voltage range, the motors going faster as the
voltage increased. Is it really a nominal voltage, as with steppers, or was
I correct? Will these motors run fine on the lower end of the range
(assuming I'm driving them with Gecko 320s), or will they lack "pep"? There
seems to be a tradeoff between volts and amps- there are motors calling for
fewer volts, but they want more amps. The ones running on higher voltage
seem to draw fewer amps. Do the former go slower but with more torque, while
the latter go faster with less? Is there a simple way to swap amps for volts
in a power supply, so one has control over this? For instance, if I have a
12v 10 amp (120 watt) supply, can I put some kind of a voltage booster into
the circuit and get 24v at 5 amps? I'm pretty sure this works in reverse- a
voltage regulator can limit the voltage, but is there a way to jack it up?]


Andrew Werby
www.computersculpture.com


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "volitan712003
<volitan@o...>" <volitan@o...> wrote:

> Thanks for all the excellent responses!
>
> If I understand correctly, stepper motors are "current" driven,
> rather then "voltage" driven. However more voltage will give you

more

> RPM's. But if I'm going to limit the voltage on the driver down to
> 2.58 volts anyway, couldn't I use a 12v power supply? I have one

here

> thats 12v and 8amps. I'm asking before I hook it up, because I'm

not

> sure I understand completely yet.
>
> If I'm using 2.58 volts and 1.79 amps, then even if all three

motors

> turn at once then the most they will draw is 7.74 volts and 5.37
> amps, pretty well below the limits of the power supply I have here.
>
> Am I thinking about this the right way?
>
> Thanks!