Re: [CAD_CAM_EDM_DRO] How many kva for a control transformer...?

Lance Hopper wrote:

>Hello,
> I'm getting ready to wire up my control for my cnc lathe
>retrofit. I've got real 220 3ph which will be used for the spindle
>motor/VFD and coolant pump. I will be needing 120V 1ph for the PC,
>breakout boards, relay coils, 5/12/24VDC power supply and my large
>36VDC 10A servo power supply. I'm thinking it would be beneficial to
>use a transformer dedicated to supplying 120VAC to the servo power
>supply, and then use the other transformer to supply 120VAC to the PC
>and everything else.
>
> What size (va or kva) transformer would be needed to power a PC,
>2x breakout boards, a small 5/12/24VDC power supply and various relay
>coils.?
>
> What size would be needed to supply 120VAC to my 36VDC ~10A
>homebuilt power supply for my servos?
>
>

36 V 10 A is only 360 VA. You can get 1700 VA out of a 15 A 120 V
outlet.

> Wouldn't it be beneficial, electrical isolation-wise, to have
>separate transformers supplying the servo drives and for the PC and
>control components? Or, should I just go with one big transformer to
>power all the 120VAC components?
>
>
>

Possibly, but most computers, etc. are pretty tolerant of noisy power.
Actually, the VFD is the real culprit, the servo drives are going to be
much more benign.

Jon