question about typical utility transformers

[danny burstein]

You may recall an earlier question I posted regarding
a garage structure in our complex. The key point was
that its load was almost entirely 24 hour HPS lighting
(about 50 kw).

That building, along with the residential structures
here, gets 3 phase feeds from transformers directly
in the street (i.e a couple of dozen feet) away.
I've measured the voltage as typically being in
the upper 120s, even in the top floors.

The lighting level in the garage is quite high, and
in a normal world we could turn off, say, 1/4 of the
luminaires and still have plenty of light. But... people
don't like seeing dark fixtures.

It struck me that reducing the voltage from the 128V
down to 120, or even 115 or 110 (all of which would
be well within specs) would (for want of a better term)
quietly reduce the light level a bit, and would save
us, perhaps, 10 percent of the power and money.

So my silly questions of today, and feel free to laugh
at me:

a: is the input/output voltage ratio on a typical underground
(in a vault with sidewalk grating) transformer reasonably
easily adjustable?

b: would the utility take us seriously if we asked them
to reduce the output level by ten percent? Or would we
be treating them to their joke of the day?

(I'm working on teh assumption the garage does, indeed,
have its own transformer.)

Thanks.

 

[danny burstein]

[ los snipped ]

It is very unlikely that your HPS lights are low power factor so
ignore that post in this thread. If they were then either you'd be
paying a low PF penalty or be required by the power company to correct
the PF at the meter in order to be serviced at all.

They're about ten years old. I was able to get one
and wire it through a KAW a year ago and saw a PF
of something like 65 percent

It seems to me that you're trying to use technology to solve a social
problem. Given the high cost of electricity in most places, the
proper approach is to turn off the appropriate number of lights and
let the tenants bitch a little. Tell 'em that reducing the lighting
load is helping put off a rent increase (or maintenance fee increase
in the case of a condo.)

I'd _love_ to do that. But it's almost impossible. I can't
even get them to agree to do a 1/2 shut off on the days
in mid summer when the utility begs for conservation...

If it really and truly is politically impossible to turn off some of
the lighting then you might want to investigate the "energy
conserving" (really slightly lower power and output) bulbs that most
of the major manufacturers make. These are designed to screw into
existing fixtures and slightly reduce both the light output and power
consumption.

Last time I looked, which was a couple of years ago, there
was no lower wattage retrofit/replacement for these (they're 90 watt
HPS lamps). I'll check again. If there si such an animal,
that would be the simplest solution.

Thanks

 

[[email protected]]

I know that this is wasted on you

Neon John, trying to win "prick of the month" again.

 

[samuel c]

You may recall an earlier question I posted regarding
a garage structure in our complex. The key point was
that its load was almost entirely 24 hour HPS lighting
(about 50 kw).

That building, along with the residential structures
here, gets 3 phase feeds from transformers directly
in the street (i.e a couple of dozen feet) away.
I've measured the voltage as typically being in
the upper 120s, even in the top floors.

The lighting level in the garage is quite high, and
in a normal world we could turn off, say, 1/4 of the
luminaires and still have plenty of light. But... people
don't like seeing dark fixtures.

It struck me that reducing the voltage from the 128V
down to 120, or even 115 or 110 (all of which would
be well within specs) would (for want of a better term)
quietly reduce the light level a bit, and would save
us, perhaps, 10 percent of the power and money.

So my silly questions of today, and feel free to laugh
at me:

a: is the input/output voltage ratio on a typical underground
(in a vault with sidewalk grating) transformer reasonably
easily adjustable?

b: would the utility take us seriously if we asked them
to reduce the output level by ten percent? Or would we
be treating them to their joke of the day?

(I'm working on teh assumption the garage does, indeed,
have its own transformer.)

Thanks.

just an idear , if people do not like seeing unlit fittings just remove
some of them and keep them as spares .
samuel c .