Re: [CAD_CAM_EDM_DRO] Re: Mariss' power supply circuit

mariss92705 wrote:

> Hi,
>
> My assumption has been this: A motor has a stall (locked armature)
> current and torque rating. The current is equal to the motor's rated
> voltage divided by its armature resisistance; the torque is equal to
> the motor's torque constant multiplied by that current.
>
> The motor will momentarily draw that rated stall current as it
> accelerates from rest when the rated voltage is abruptly applied.
> That is exactly identical to shorting a motor running at its rated no-
> load speed. Both currents will be identical and within ratings.

Absolutely not true for a servo motor! For instance, I have some
90 V motors with roughly 1 Ohm armature resistance. These motors
would draw roughly 90 Amps at full supply voltage. This would ruin
the field magnets, as the manufacturer's instantaneous peak current
rating is something like 17 Amps.

Jon