Re: [CAD_CAM_EDM_DRO] Re: query - 2HP PM DC motor controller - pointers please

Jan Kok wrote

How does one get 90VDC from 110VAC? By using a switching power
supply, or
PWM? (In which case there is nothing magic about 90V, you could get any
amount of DC up to sqrt(2) * 110V minus a few volts for various losses.)

The peak volatge of a 120 V line is actually 167 Volts. The effective
heating voltage
a resistor would see is 120 V, that is called the RMS, or
Root-Mean-Square, voltage.
it would be a good safety feature to use an isolation or step-down
transformer, but you
don't have to. A number of spindle drives are direct coupled.

Jon