On 10/15/22 16:15, John Dammeyer wrote:
On 10/15/22 14:17, andy pugh wrote:
On Sat, 15 Oct 2022 at 18:02, John Dammeyer <jo...@autoartisans.com> wrote:
What would a working STMBL go for nowadays? One can buy servo motor/drive
combinations as cheap as
$200 from China although shipping is a bear.
The STMBL really shines as a retrofit drive, as it can be persuaded to
work with almost anything. It's also rather nice having digital
position control via smart-serial.
But given that they don't really exist at the moment, it's difficult
to recommend them.
If you've the time Andy,, some of us would like a history of STMBL, and
why they don't exist today?
Cheers, Gene Heskett.
Might be past Andy's bedtime now so I'll add my two cents. First check out
this web link.
https://github.com/rene-dev/stmbl
Then read the getting started guide which fills in a lot of the blanks.
Now. Why is it not available? Two reasons. The key thing about the STMBL for
3 phase AC servos was that it used single driver for all three windings.
Probably originally designed for washing machines. It was discontinued. A
different one with slightly lower power was available. There are others but
different pinout so board change.
It uses two processors. One for the high voltage side and communication with
the other one is done optically for full isolation. The main processor does
all the interaction with the outside world. The smaller driver processor
apparently is currently sitting with a more than 1 year delivery date. That
may have changed.
Not only is the schematic open source but so is the software. Truly one of the
great projects released over the last few years. I have it connected to my
harmonic drive which is AC servo based.
I never did get it working with the brushed DC motors. Only the STMBL designer
appears to have used it with a DC motor and otherwise seems no one else has so
support was essentially non-existent. I went back to using the HP_UHU drives
until I swapped them out for Bergerda AC Servos.
John
Brushed PMDC motors are Pico Systems PWM-Servo driver territory, up to 2
or 3 horse. I'm running two of them, good control,
and bullet-proof. With 1hp motors, rated 90 volts, 9.7 amps FLA, I'm
banging two of them at 125+ volts and have the current
limiters set for around 18 amps. If I hang the cut, stopping the motors,
I can hear the iron chirp as the current limits kick in,
and at least once I was out refilling my coffee cup, to come back and
find it sitting there complaining. I twisted the shaft off
an identical rated treadmill motor once, but that driver has survived
everything I've thrown it at, one of them for 7 or 8 years now.
That servo amp is a full 4 quad amp, and a quick reversal will push the
psu to around 175 volts, which it then uses to accel
in the other direction. No shop light blink from a 400 millisecond
reverse from wide open to wide open in the other direction.
However, I had to get creative in hal, intercepting the reverse,
generating a stop instead, wait for it to stop by watching the
encoder, then let the reverse thru to the controller and bring it back
up to speed.
Jon Elson makes good stuff.
Take care and stay well John D.
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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