🚀 go-pugleaf

elelyc@nuscc.nus.sg (Y.C. Liang) writes:

> In article <17gjq9INNi66@venture.ksu.ksu.edu> misra@venture.ksu.ksu.edu (Boo!
> >
> >	Help me out a bit here, what is the main difference between 
> >adjustable and variable speed drives. The books i have refered to tend
> >to use them as though they are the same. Perhaps they are. From what I 
> >gather, varible speed drives change speed depending on the load and adjustab
> >speed drives run at 'adjusted' speed regardless of what the load is. 
> >I am sure I am missing some basic concept here. Thanks for any help you
> >can give me. 
> >
> >						misra@matt.ksu.ksu.edu 
> >
> I think they are the same thing.  Sometimes, people prefer to use
> different names.  Regards.
> 
> 

If you want accurate speed control, then you choose a SERVO controlled 
design that has speed feedback thru a tach circuit of some sort, OPEN 
LOOP speed controls aand CLOSED loop speed controls are the 2 categories 
of adjustable speed control drives.  Disk drives used CLOSED loop motors 
for spindles and rotary voice coil motors.  Steppers motors are open 
loop, but because the steps are quantized and measureable, they can be 
made into accurate speed controls. Some have slew up/down acceleration, 
control circuits.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607