Inverter use Emergency Lights

[Mark]

I am thinking of using a ups/inverter to power emergency lighting.
Is there any problem powering T8 Fluorescent lamps from an inverter?

 

[Victor Roberts]

I am thinking of using a ups/inverter to power emergency lighting.
Is there any problem powering T8 Fluorescent lamps from an inverter?

We just went though this discussion for CFLs. In most cases you will
not have any problem. I assume you are using electronic ballasts.
There may be some unusual electronic ballasts that are not happy with
the waveform supplied by the inverter, but they should be rare, as
long as the inverter generates a pseudo-sine wave instead of a square
wave.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

 

[Clive Mitchell]

I am thinking of using a ups/inverter to power emergency lighting.
Is there any problem powering T8 Fluorescent lamps from an inverter?

My experience of running compact fluorescent lamps from a UPS suggests
it's fine, but be aware that the manufacturers get extremely creative
with their load running times. When they say something like 800VA UPS
runs load for up to 60 minutes, they don't mention that the full 800VA
load will probably just run for five minutes. On a Trust 800VA unit I
could run 20 5W CFL's for a max of 25 minutes but would say that 20
minutes is a safer figure.

Keep in mind that depending on where you live, the regulations for
proper emergency lighting may require a 3 hour run time with quick
recovery when power is restored.

 

[Victor Roberts]

the normal input to any tronic balalst is a bridge rec + reservoir, so
i doubt wave shape would be a problem, with one proviso: a mod-sq
invertor would need to have surge curretn rating of several times the
lighting run current.

I don't understand what you mean by "bridge rec + reservoir" but the
input circuits of some electronic ballasts provide DC voltage equal to
the peak of the input sine wave. For the same RMS voltage, a square
wave has only 70% the peak voltage of a sine wave, so electronic
ballasts that provide a DC link voltage equal to the peak of the input
waveform will not operate correctly with square wave input.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

 

[Victor Roberts]

MSW invertors, also loosely known as square wave invertors, do not
produce square waves. They produce a modified square, with the same
Vpeak and Vrms. Thus Vpeak is not an issue.

Enough with the word games. When I said "square wave" I meant "square
wave." If you or other people want to use the term "square wave" as
shorthand for "modified square wave", the confusion that is created by
the use of this shorthand is your problem

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

 

[Victor Roberts]

There is no such thing as a square wave UPS, theyre all MSW or sine.

That may be true.

MSW are often called square wave,

I do not believe it is possible to have a meaningful technical
discussion if people are going to misuse standard terminology just
because it is convenient for them to do so.

just as triphosphor are often called
full spectrum.

There is no standard definition of "full spectrum" so in this case we
are each free to make up our own, However, tri-phosphor lamps are the
opposite of most definitions of "full spectrum" that I have seen.

About as accurate.

Yes, just about ...

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

 

[Victor Roberts]

Accept it, you just werent aware of the standard terminologies, and the
fact that theyre easily misinterpreted. No good claiming it was my
fault

You may want to take a look at the following four sites:

http://www.solaralaska.com/primer/inverter.htm

http://www.energyalternatives.ca/SystemDesign/inverters1.html

http://www.solarelectricsupply.com/Inverters/inverters.html

http://www.q3wholesale.com/Resources-sinewave-guide.htm

They each discuss three different and distinct waveforms produced by
inverters: square wave, modified sine wave (also called modified
square wave in the third reference) and sine wave. The fourth site
even has waveforms.

There seems to be no question that the inverter industry does not use
"square wave" when they mean " modified sine wave" or "modified square
wave".

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.