Re: [CAD_CAM_EDM_DRO] Servo motor HP for Bridgeport

info.host@... wrote:

> > All stepper systems need a power supply that is higher than the motor's
> > rated voltage to overcome the inductance (think of it like inertia of the
> > current) in the windings.
>
> I understand now, I hope. Why is it that servos don't also need the high
> voltage? As the frequency of the steps going out to the stepper increases
> what happens to the voltage needed to supply to correct current? Does it get
> higher because the higher frequency passes through the coils worse?

Yes. If you didn't have the chopping of the input voltage, the current would
rise
to excessive values. When current reaches the setpoint, the chopper turns
the voltage off.

With a brush-type servo motor, the inductance of the individual armature
coils is very small. Only two coils (not the whole armature winding) change
polarity every time a set of commutator slugs pass the brushes. the entire
armature winding flips polarity only twice per full revolution of the motor.
A typical stepper requires this FIFTY times per revolution! That is why it is
much more of a problem with a stepper.

> I'm only
> remember that with N2 lasers the laser uses a wire to connect two plates of
> a capacitor together so they can charge and start the gas lasing in the
> cavity. But then when the spark gap breaks down the frequency rockets and
> the wire connecting the plates becomes 'invisible'. Am I talking nonsense?

Sounds something like exploding wire technology. I'm more familiar with
plain spark gaps being used to start lasers. There was a pretty famous
transmission-line spark gap N2 laser from Scientific American.

Jon