Re: Stepper motor from Sherline?

Randy,

As Dan has told me, the 18v is not really a limitation, there is an
onboard regulator for the 5v, it will run too hot if higher voltages are
used. Put a series dropping resistor in it's supply lead, to "eat up"
some of the voltage drop. Then I think he said it should be good to
about 30+ volts or so (Dan, correct me if I'm wrong!).

I didn't convert 9.7kg-cm to get 110 oz/in. I convert 9.7kg-cm to
134.43 oz/in. I got 110 oz/in from Bryan Mumford's website:

http://www.bmumford.com/rotary/index.html

"The motor has a holding torque of 110 oz/in and speeds as fast as 50
degrees per second can be acheived."

In an email to me he stated:

> " The stepper motor is 135 oz/in (the Sherline spec says 100 oz/in ...
> they are overly conservative) and draws 2 amps. I forget the voltage,
> because we drive it with a current chopper supply that feeds it 24
> volts and limits the current. "
>

So there you have it. I'd seen the price for the motors too, real
tempting! Now if I could get some code written for a PIC micro!

Alan


Randy Gordon-Gilmore wrote:

>
> Mike, Tim and Alan,
>
> Thank you for your encouraging replies. I will order 3 of the motors later
> this week. Did I convert the 9.7kg-cm holding torque wrong, Alan, or is
> there some derating?
>
> I do have one Eastern Air Devices LA23DGK-2 motor rated at 4.8V, 2.00A,
> 210oz-in holding torque when connected bipolar, which I could use for the Z
> axis. But with my spring counterbalance, I might not bother. Is there
> such a thing as using *too* powerful a motor?
>
> It looks like Dan Mauch's chopper driver would work for these, except for
> the 18V limitation... Dan, if you're reading this, what would I need to do
> to use 24V with your driver? Would it be a heat dissipation issue or are
> there other component limits?
>
> Best regards,
>
> Randy
>
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