120-277 volt ballast.

[J.P.]

I was reading a bit of the 208 wye, delta high leg post and saw the op wondering what single phase loads he could use the high leg for......

So, when a ballast is rated 120~277volts such as on those atlas T5 high bay lights. They run on single phase only.

Does that mean 120v OR 277v? Only those two voltages.

Or does that mean 120v through 277v? Basically every high leg voltage would be ok to run the lights?


Normally when I use these lights it's in a new shop and the power is a 120/208 wye. Not many high legs left except old shops and farms.

 

[junkhound]

120v through 277v?

Nearly all 'universal' electronic ballasts will operate on 100 thru 300 V. Internal electronics generally boosts the ac voltage to 400 or so volts dc in the power factor correction circuit; although at 300 V the PF correction circuit does not correct PF to near unity as well as at 277 or below.

Also, though not per code (due to wire colors, etc.) most electronic ballasts have both input wires totally isolated from ground and can be used phase to phase on 120/208 or on 240 single phase, though you need to know the internal circuitry to know if it would be safe. Most eb don't care (technically speaking as the electrons follow disregarding code) if the white or black wire is hot; but again, you would need to know the internal circuitry to tell for sure.

 

[iwire]

So, when a ballast is rated 120~277volts such as on those atlas T5 high bay lights. They run on single phase only.

I would say if it is marked 120 - 277, that it is 120 through 277. If it is marked 120 / 277 it is either one or the other.

That is how motors and other equipment is marked.

For instance a motor marked 200-230/460 can be run on 200 through 230 or be connected differently for 460 specifically.

 

[Sparky3141]

Interesting question as I do a lot of lighting but I never considered this. We still have a few old delta systems in and around Pearl Harbor ( as well as some ungrounded systems).

Pulled this off of a Phillips spec sheet:

http://www.usa.lighting.philips.com/pwc_li/us_en/connect/advance/assets/1-01_to_1-69_Atlas2012.pdf

Input Voltage (dedicated vs. multi). Most ballasts are designed to operate at specific voltages. Newer electronic ballasts, including Philips Advance models that use IntelliVolt technology, offer much greater flexibility and other advantages such as inventory reduction. Today?s increasing demands on electrical utilities can cause wide voltage variations during load demand changes which in turn cause light output from lamps operated on dedicated electronic and electromagnetic ballasts to vary with the input voltage changes.
With IntelliVolt technology, many Philips Advance ballasts maintain constant light output through nominal input voltage ranges of 120
to 277 volts, thereby compensating for any change in input voltage. Some ballasts operate from 277 to 480 volts or 347 to 480 volts


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