Efficacy of multi tap ballst VS single voltage ballasts

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Terry Shelton Sr

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I am researching installing 300+ 80watt Inductive fixtures in our parking structure. most that I have looked at have multitap ballast. one manufacturer is offering a single voltage 277 Volt modael that they claim has less ballast loss than multi tap. Is this valid or mis information to hype their product.
 
Terry, welcome to the forum! :)

A multi-tap ballast is merely one whose primary winding is one of the highest voltage (277), with taps at each of the other voltages. If you feed 120v into the 120v tap, the 277v tap will have 277v on it.

I could see their theoretical point in needlessly "creating" that unloaded 277v if you were using the 120v tap, but all you'll have is 277v on the 277v winding, with unused taps between. I see no difference.

No matter which tap you use, the same volts-per-turn will be created, resulting in one secondary voltage. Also, the same power is used from the primary, so the lower the voltage, the higher the current.
 
I never thought about that before but I believe you are correct in the taps having their assigned voltages.I guess that occurs from an induced voltage from the secondary winding,kinda like a boost xfmr.

dick
 
I think that the loss is so small it isn't a problem. You may think about the induc./cap. of the total load if putting some load on to an emergency gen. set.
 
dicklaxt said:
I never thought about that before but I believe you are correct in the taps having their assigned voltages.I guess that occurs from an induced voltage from the secondary winding,kinda like a boost xfmr.
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If any winding or winding segment is supplied with its design voltage, every winding or winding segment will develop its design voltage.

The energized windings determine the volts-per-turn ratio for the entire transformer. The same applies to standard or auto-transformers.
 
I see no reason to doubt the manufacturer right out of the starting gate. who is it ? can you post the information or a link ? How much of a difference are they claiming ?
 
Of all magnetic HID ballasts, simple series reactor type offers the worst regulation (ability to compensate for line voltage fluctuation), but the highest efficiency.

http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/mwmhl/ballastTypes.asp

http://www.venturelighting.com/Literature/BallastGuide.pdf

Dedicated voltage series reactor is the cheapest, and offers the best efficiency, although with as many fixtures you're installing, you shoud specify optional parallel capacitor to raise power factor, so that you can maximize the capacity of your circuit.

Multi-tap is great for maintenance stock so its not necessary to stock different ballasts for each voltage used at facility, but for a new install on same voltage, you can probably get a better pricing on dedicated voltage ballast.
 
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Electric-Light said:
Of all magnetic HID ballasts, simple series reactor type offers the worst regulation (ability to compensate for line voltage fluctuation), but the highest efficiency.

http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/mwmhl/ballastTypes.asp

http://www.venturelighting.com/Literature/BallastGuide.pdf

Dedicated voltage series reactor is the cheapest, and offers the best efficiency, although with as many fixtures you're installing, you shoud specify optional parallel capacitor to raise power factor, so that you can maximize the capacity of your circuit.

Multi-tap is great for maintenance stock so its not necessary to stock different ballasts for each voltage used at facility, but for a new install on same voltage, you can probably get a better pricing on dedicated voltage ballast.
Click to expand...

Thanks for the links Electric-Light.:grin:
 
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