Re: What makes a motor a servo? calculating power

>
> OK, so my question is about power in the calculation. at what point
> do you select power for either type of motor ?

Don't. I don't agree with Mariss that power is the bottom line.
You need to select a torque and RPM curve that fits your
application. Power is just the result of these 2 factors, but
not something to be directly chosen. The Power number in Mariss'
calculations is what made the servo appear to be performing worse
than the stepper. The example he posted is completely deceptive
since he is assuming that the servo is putting out maximum power
when it is rapiding. That is not the case. At slow cutting speeds,
the servo is actually using less power than the stepper, yet this was
not pointed out. Where do you spend your time, cutting material or
doing rapids?

>
> Is my NEMA42 800oz in motor just as good as a NEM34 800oz-in motor? I
> thought there were reasons the NEMA42 were not as good.

NEMA is just a frame size and has no bearing on the motors performance.

> As for servo's. how do you calculate for a 230 volt motor that is
> rated for 1-1/2 hp and 5,600 rpm when you are going to use a Gecko on
> it with a 66 volt power supply ?

Sounds like trial and error to me.


Scott