Re: big lathe, big motors may have both armature and field windings

> From: Doug Fortune <pentam@...>

<s>

> There is a Reliance V*S SpindleDrive variable spindle
> speed control unit about 14"square x 4" thick that
> seems to convert the 480V AC into 240V DC, and it looks
> Ok.

The following is not intended to take anything away from the
awesome Geckodrive or it's equally helpful owner.

IMHO - Most anytime you can use the mating drive with a variable speed
motor you are miles ahead of a retrofit in that area. My reasoning here is
that you take advantage of the engineering that was done for the system
when it was designed and built.

The biggest problem that you will have with this vintage driver is that
some of the smaller capacitors will be changing values as they age. It
might pay to have a local "radio" guy check them out and replace the bad
ones. Then with a little tuning, you'll have a unit that will last many
years. My guy here has an in-circuit tester and the job takes a few
minutes and costs a few bucks.

<s> The two servo motors are a mystery: Kollmorgan Corp

> Inland Motor Division Model TTR-4030-102-A
> continuous 15V 20 Amps 10 lb*ft torque ie 1920oz*in
> peak 67V 90 Amps 45 lb*ft torque ie 8640oz*in
> max rpm 2000

Kollmorgan makes some very nice systems. The drivers for these should also
be in there somewhere. They are a mil spec company and make systems for
subs and ships so the stuff they make is solid.

I maintain one system here (1988 or so) and the drives are cards that plug
into a rack with power and signal jumpers across the front. The rack
includes the power supply. I keep a spare drive board around but haven't
had to replace one for a couple of years now. I've never had the power
supply go bad.

Kollmorgan has good service on these units but I suspect that what you
are finding with e-mail is that the web group is not the service or
help group. I think that I can get you a people number if you decide to
save the drives.

But if you decide to go the replacement route, Jon Elson recently posted
about using a simple constant voltage DC supply for field and the Gecko
servo driver. I suspect that you wouldn't get quite the same performance
but I'm thinking of doing the same thing here with an old, slow moving flame
table.

HTH

Ray