I grew several kinds of orchids under lights some years ago. I had a 2-layer
stand that had two shop lights for each level.. Each shop light had two
40-watt tubes.

Mostly cats and a few phals, but they bloomed faithfully. Aside for watering
and feeding, etc. I had the lights on a timer that was changed so that they
were on about the same length time time as the sun shone. (The plants never
got any direct sun.)

I changed the timer when I noticed a difference between the timer ON and the
length of time that the sun was 'shining'.

Good growing.....
Chris