Re: RF-45 Mini Bed Mill

WAnliker@... wrote:

>
> How can you identify which tape drive motors are the desirable ones. There
> are several floating around here. But you have to be able to say yes or no
> by looking inside of the cabinet, and oftentimes you can't get a very good
> look. Are both of the motors the same?

Well, you want a tape drive that has fast acceleration, and uses the motors
to directly drive the tape hubs. A start/stop drive of 45 IPS would be marginal,
a streaming drive of 75 IPS would be a little better. A start/stop drive of
75 IPS would be good, 125 IPS would be ideal. Some drives that come
to mind are the Pertec T1000 drive, sold as the Digital TU77 and TU78.
The capstan motor out of these is also quite good. These drives are generally
in their own, floor-standing rack. A Pertec T9000 series, 75 IPS start/stop,
is also pretty good. A start/stop tape drive is identified because it has
some kind of buffer between the tape over the head and the reels, either
spring-arm (slow) or vacuum-column (faster). It will also have a capstan
roller to drive the tape across the head. These are usually extremely fine
low-inertia servo motors, but generally have pretty low torque. But, they
are good for other applications.

The reel hub motors may be the same, or similar. Some streaming drives
have optical encoders on only one motor. The capstan motors (in drives
that have them) will be much different than the reel hub motors.

Jon