Shopsmith Forums

wa2crk wrote:dlbristol
FYI Teknatool has a good basic tutorial on the DVR motor on their website Teknatool.com
Bill V

Are all DVR motors the same?

Are the DVR motors in the Lathe and the PowerPro the same?

Are there algorithms applicable to the DVR that are NOT applicable to the PowerPro and vice verse.

JPG40504 wrote:When I learned Fortran, the version number needs not only a hand less a thumb, but two less fingers also!

As I understand it, an electronic module interfaces with a speed detector and the control panel(and the power source). I contains a processor(mini-computer). The motor coils are controlled by this module.

In addition to the power train, the various SPTs exhibit widely varying load characteristics not only singly, but also in combination if simultaneously 'mounted'.

The load variations are much more complex than a relatively simple lathe load(cutting action etc.). They also will have a different period(1/frequency) than the motor(not like a direct drive lathe spindle).

In short, be patient. This is not a trivial undertaking(IMHO).

So is the speed sensor inside the motor? If so then I can understand why the settings are hard to get right. The micro-pulses are trying to maintain a constant speed setting with various loads that have different inertia and drag.
My Fortran was on punch cards. I don't remember a version number.

dusty wrote:Are all DVR motors the same?

Are the DVR motors in the Lathe and the PowerPro the same?

Are there algorithms applicable to the DVR that are NOT applicable to the PowerPro and vice verse.

Thanks to riot_nrrd on another post, the Teknatool original is seen to offer operator choices for feedback parameters. See the page 31 citation he found:
http://www.teknatool.com/products/Lathe ... uly_09.pdf

The Power Pro to date offers no customer choice for these parameters, although they can be accessed in some fashion by calling "Wes." I suspect in a future design this may change.

JPG40504 wrote:....In short, be patient. This is not a trivial undertaking(IMHO).

This is me - being patient!:) In my pea sized brain, I suppose not only load characteristics of SPTs, but also the variability of the tightness of the two drive belts could cause different loads.

If the motor mounts had to be loosened in order to fit the long belt, how could a person duplicate the desired tightness? All that was said on the DVD was tighten (or loosen) the adjusting screws equally. Also said the bottom belt had to be tight! After this, was the adjustment of the eccentric to get lowest noise.

The bottom line for me is - The machine works beautifully for all purposes!:D I have to be careful when bandsawing tight curves. The PowerPro is fun!!!! It would be even more fun after we get the issues resolved.

MikeG wrote:So is the speed sensor inside the motor? If so then I can understand why the settings are hard to get right. The micro-pulses are trying to maintain a constant speed setting with various loads that have different inertia and drag.
My Fortran was on punch cards. I don't remember a version number.

Ditto! So was a lot of other stuff(almost all) way back then. When you had trays of input/program cards, you appreciated the sequence number. This was b4 'TSO'. Cards were the only input medium!!!! Cards and printer the only output!! Good old days!?

MikeG wrote:So is the speed sensor inside the motor?

It's a circuit board on the motor and it reads a plate attached to the motor spindle - under the black plastic cover. If you look at the troubleshooting, there is a section that talks about realigning the plate to the sensor. The sensor is an infrared pickup that is looking for some binary indictor (not sure if it's paint, finish, scratches, or what) on the rotating disc. So it is effectively counting RPMs.

The motor has two connectors - a thin 5-wire set for the sensor, and a heavier gauge set that drives the motor.

Those connect to what ShopSmith calls the "Power Supply," but I'm about 99.9% sure has all the brains as well. That conencts by another thin wire to the control panel/display. Power is conected via another set of cables.

MikeG wrote:My Fortran was on punch cards. I don't remember a version number.

Nice! I played with used punch cards when I was a kid, but by the time I was old enough to get my hands on a computer, they were gone. It's hard to beleive that we now have gigabytes of storage on cell phones, gigabytes of memory on PCs, and terabytes of storage on home NAS devices. What hapended to terse code that exectured in 8 kilobytes of working memory? Now everything sucks up all the room it can.

JPG40504 wrote:Ditto! So was a lot of other stuff(almost all) way back then. When you had trays of input/program cards, you appreciated the sequence number. This was b4 'TSO'. Cards were the only input medium!!!! Cards and printer the only output!! Good old days!?

I also did punch cards and the danged compiler that handed you back all of the cards telling you there was some problem some where and you needed to fix it! I developed a real appreciation for the folks who could do that well and I buy their programs with even greater appreciation. same applies to something like PP, I could never do that,but I sure appreciate the brains it takes to make stuff work. And thanks for the site with the info on the motor.