RE: Testing Step Motors

> -----Original Message-----
> From: Harrison, Doug
> Sent: Thursday, November 18, 1999 4:19 PM
> To: 'PTENGIN@...'
> Subject: RE: [CAD_CAM_EDM_DRO] Testing Step Motors
>
> Hello Peter;
>
> I suspected that others out there were having problems with Microkinetics
> equipment. I will be happy to share my experiences for the benefit of
> those interested.
>
> Last year I bought a Driverack system with the DR8010 amps, Optistep card
> and Millmaster software. This was to replace the aging BOSS 5 controller
> on the Bridgeport at the tech school where I teach. The BOSS-5 must have
> sensed its pending termination and immediately mended its ways. So we
> never did change the controller. We opted to use the Driverack system as
> a simulator for G-code training. It serves this purpose well.
>
> This year I ordered an identical system for a machine of my own. It
> arrived two months later with one bad motor. I borrowed a motor and got
> it running on my machine, only to find that vibration was so bad at some
> frequencies it would occasionally just sit and growl without moving. Sent
> it back (along with the motor) and had microstepping drives put in. Got
> it back six weeks later with badly damaged case and handles. Hooked it up
> and it worked great until the smoke came out an hour later. The soft
> start resistor was blown and arcing had occurred near the line power
> terminal block. Sent it back again. Got it back in only a week (we are
> one day from Kennesaw, GA). Case and handles were bent again. X and Y
> worked but Z had been disconnected. Rewired it myself. The resistor had
> been replaced but the terminal block, which was cracked, had not been.
> Nor had the wires been re-routed to prevent arcing as was discussed.
>
> The system is now working. Line filtering is inadequate, as is evident in
> the behavior of the monitor. Jogging is slow. Wiring in the cabinet
> looks like a rat's nest. Motor cables are undersized. A hardware lock
> for such low end software seems silly, particularly when it only works
> with their board. The promised free software updates are of little value
> if they don't update it.
>
> The biggest problem is that I have lost several months work due to
> downtime for what was supposed to be a bolt on and go system. After
> getting the unit back damaged for the third time I attempted to invoke
> Microkinetics' money back guarantee. I was told that the 30 days had run
> out. They apparently ran out before it arrived the first time.
>
> I have $3,700 (with much shipping) in this equipment and have lost twice
> that much in contracts because the machine was down. In all fairness I
> must admit that the folks at Microkinetics have been friendly, cooperative
> (except for not honoring their guarantee) and helpful. However, I would
> not recommend their products based on the experience I've had.
>
> Doug Harrison
>
>
> -----Original Message-----
> From: PTENGIN@... [SMTP:PTENGIN@...]
> Sent: Thursday, November 18, 1999 1:37 PM
> To: dharrison@...
> Subject: Re: [CAD_CAM_EDM_DRO] Testing Step Motors
>
> In a message dated 11/18/1999 3:01:49 AM Hawaiian Standard Time,
> dharrison@... writes:
>
> << I recently purchased a Microkinetics Driverack system. Not too
> happy with
> it, but that's another story. >>
>
> Doug,
> How and why were you not happy? I got my driverack with the
> DM4050
> drivers. What a mistake. MicroKinetics doesn't even filter in coming
> power in
> their design. I had my father go over the electronics and he also
> said the
> filtering on the pwr 3610 power supply was inadequate. I put in
> parallel some
> 58,000uf at 50 volt power caps and smoothed it a little but I need
> larger
> supplies. The lines from the input connector to the driver cards are
> not
> shielded on mine. I was getting all kinds of crosstalk. Lost steps,
> additional steps, all around instability. We also found that opto
> isolator
> power to the optistep card from the driverack was dirty. We put some
>
> filtering on the optistep card's external power line. We put a 20
> amp inline
> filter unit on the 120 VAC input power. We also replaced the power
> leads to
> the motors with shielded cable. The DM-4050's were prone to
> overheating so we
> got AMP 7080 driver cards instead. These are 7 amp 80 volt cards
> from Applied
> Motion Products.
> Once I had all these changes, I realize I could have boxed up
> the unit,
> made believe I never bought it and built my own. I did in the end
> anyway in a
> round about way. I will go to 48 volt 50 amps supplies from a
> scrapped
> telephone system soon. I need to fuse the inputs to the drivers so a
> short
> don't explode anything!!
> My machine now (FB-2) now runs at over 60 inches a minute. And
> yes, I can't
> jog very fast. They (Microkinetics) are so close to a workable
> product. It's
> amazing they don't go under. I guess many systems do work.
> I'd really like to hear your story, on the group or direct to me.
>
> Thanks very much.
> Peter Tsukamoto
> THRD, Inc.
> <A HREF="www.hipertee.com">Hi-Per-Tees</A>