I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts,
or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

ps56k wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts,
or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

They use 40W, they will be producing the light equivalent to ~150W of
incandescent lamps. Unfortunately, few people these days seem able to
understand what efficiency really means, or calculate the MPG their car
gets

wrote:

On Mon, 19 Nov 2012 12:23:22 -0600, "Pete C."
wrote:


ps56k wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts,
or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

They use 40W, they will be producing the light equivalent to ~150W of
incandescent lamps. Unfortunately, few people these days seem able to
understand what efficiency really means, or calculate the MPG their car
gets

Just a little gee whiz info
I put a clamp on the hot side of the line cord of a regular 2 tube
shop light and the whole thing, ballast and all is about 0.48-49 amps
and a line voltage of 123 VAC so the whole thing is about 60 watts.
I am not sure where the "40w" comes from.
Maybe that was based on the old style magnetic ballast.

True RMS meter? The missing 20W could be hiding in a distorted
electronic ballast waveform.

wrote in message
...
On Mon, 19 Nov 2012 12:23:22 -0600, "Pete C."
wrote:


ps56k wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually
using 40
watts,
or is that just and equiv and the real watt usage is much less, just
like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a
normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

They use 40W, they will be producing the light equivalent to ~150W of
incandescent lamps. Unfortunately, few people these days seem able to
understand what efficiency really means, or calculate the MPG their car
gets

Just a little gee whiz info
I put a clamp on the hot side of the line cord of a regular 2 tube
shop light and the whole thing, ballast and all is about 0.48-49 amps
and a line voltage of 123 VAC so the whole thing is about 60 watts.
I am not sure where the "40w" comes from.
Maybe that was based on the old style magnetic ballast.


ok - was curious enogh to break out my Kill-A-Watt meter...
as the twin tube shop light is plugged into a switched outlet.

SO - the lamps are - F40RES SP41 40w

The meter shows the fixture with both tubes running -
124v .86amp 67watt 105va ..... that's 67watts total for BOTH running

wrote:

On Mon, 19 Nov 2012 13:21:48 -0600, "Pete C."
wrote:


wrote:

On Mon, 19 Nov 2012 12:23:22 -0600, "Pete C."
wrote:


ps56k wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts,
or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

They use 40W, they will be producing the light equivalent to ~150W of
incandescent lamps. Unfortunately, few people these days seem able to
understand what efficiency really means, or calculate the MPG their car
gets

Just a little gee whiz info
I put a clamp on the hot side of the line cord of a regular 2 tube
shop light and the whole thing, ballast and all is about 0.48-49 amps
and a line voltage of 123 VAC so the whole thing is about 60 watts.
I am not sure where the "40w" comes from.
Maybe that was based on the old style magnetic ballast.

True RMS meter? The missing 20W could be hiding in a distorted
electronic ballast waveform.

That might be true, the DL250 manual says

"AC readings displayed on this meter are average responding, True-RMS
indicating. They are based on a true sinusoidal waveform."

The T8 tubes are 32W also, while the T12 are 40W. Not sure which you
have in the fixture you measured.

ps56k wrote:

wrote in message
...
On Mon, 19 Nov 2012 12:23:22 -0600, "Pete C."
wrote:


ps56k wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually
using 40
watts,
or is that just and equiv and the real watt usage is much less, just
like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a
normal
bulb.
--
/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/
No Good Deed -
Goes Unpunished

They use 40W, they will be producing the light equivalent to ~150W of
incandescent lamps. Unfortunately, few people these days seem able to
understand what efficiency really means, or calculate the MPG their car
gets

Just a little gee whiz info
I put a clamp on the hot side of the line cord of a regular 2 tube
shop light and the whole thing, ballast and all is about 0.48-49 amps
and a line voltage of 123 VAC so the whole thing is about 60 watts.
I am not sure where the "40w" comes from.
Maybe that was based on the old style magnetic ballast.


ok - was curious enogh to break out my Kill-A-Watt meter...
as the twin tube shop light is plugged into a switched outlet.

SO - the lamps are - F40RES SP41 40w

The meter shows the fixture with both tubes running -
124v .86amp 67watt 105va ..... that's 67watts total for BOTH running

Interesting. So I went out to my shop where I could conveniently measure
on four identical cheap shoplight fixtures all populated from the same
case of Sylvania Octron/Eco F032/T41/Eco 32W lamps. After a warmup
period I measured: 56W, 57W, 57W, 60W. So there is some variation and
all seem to be a bit below the 32W spec on the tube.

"Pete C." wrote in message
. com...
SO - the lamps are - F40RES SP41 40w

The meter shows the fixture with both tubes running -
124v .86amp 67watt 105va ..... that's 67watts total for BOTH running

Interesting. So I went out to my shop where I could conveniently measure
on four identical cheap shoplight fixtures all populated from the same
case of Sylvania Octron/Eco F032/T41/Eco 32W lamps. After a warmup
period I measured: 56W, 57W, 57W, 60W. So there is some variation and
all seem to be a bit below the 32W spec on the tube.

I'm guessing that is for the fixture - with two bulbs lit up -

BTW - looked up that various flavors of my F40's - looking for "lumens"
and they appear to supply.... 2600 - 3150 lumens -
so a lot of light for wattage used -

hmmm -
single F40 straight bulb
2600 lumens / 34 watts = 76 lumens per watt

a stanard 60watt CFL
900 lumens / 14 watts = 64 lumens per watt

"ps56k" wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts, or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.

Watts are a measure of power consumption, not light produced. What you need to
be looking at are lumens. Those old 40w 48" tubes lumen output varied, but 3200
lumens is a reasonable average. A 14w CFL produces about 800 lumens, which means
you'd need 4 of them to produce the same light as an old tube.

BTW - the current 48" tubes are 32 watts for a similar lumen output.

Ps56k:

A 40 watt fluorescent tube produces about the same amount of light that three 13 watt CFL's would, or about the same as three 60 watt incandescent lights would. Incandescent bulbs use a lot of electric power because most of the electric power they use is converted into heat, not light.

Gfretwell:

I'm with Pete C. on this one. The formula Watts= volts X amps only applies to a pure resistive load, like a toaster or incandescent light bulb. Once you stray from a purely resistive load, you have to account for the "impedance" of the load, and the formula becomes Watts = volts X amps X power factor. The power factor is the ratio of watts that you pay for versus the VA consumed, and is always a number less than one. Typically, utilities don't charge residential or commercial customers for the VA consumed, only the watts used. But, when it comes to factories (that typically have a lot of electric motors) then electric utilities will charge for the VA consumed, not just the watts. That's why you often see large capacitors on the grounds of factories. The purpose of those capacitors is to raise the power factor of the factory closer to 1.0 to save on their electricity bill.

In a fluorescent light, you have a large transformer that converts the 120 volts supplied to the light fixture to about 25,000 volts AC for the fluorescent tube. It's the impedance of that transformer that accounts for the difference between the actual 40 watts used and the "about 60" volt amps consumed.

Ps56k:

A 40 watt fluorescent tube produces about the same amount of light that three 13 watt CFL's would, or about the same as three 60 watt incandescent lights would. Incandescent bulbs use a lot of electric power because most of the electric power they use is converted into heat, not light.

Gfretwell:

I'm with Pete C. on this one. The formula Watts = volts X amps only applies to a pure resistive load, like a toaster or incandescent light bulb. Once you get away from a purely resistive load, you have to account for the "impedance" of the load, and the formula becomes Watts = volts X amps X power factor. The power factor is the ratio of watts that you pay for versus the VA your appliance consumed, and is always a number less than 1.0. Typically, utilities don't charge residential or commercial customers for the VA consumed, only the watts they used. But, when it comes to factories (that typically have a lot of electric motors) then electric utilities will charge for the VA consumed, not just the watts used. That's why you often see large capacitors somewhere on the grounds of factories. The purpose of those capacitors is to offset the impedance of all the electric motors in the factory, thereby raising the power factor of the factory closer to 1.0 to save on their monthly electric bill.

In a fluorescent light fixture, you have a large transformer that converts the 120 volts supplied to the light fixture to about 25,000 volts AC for the fluorescent tube. It's the impedance of that transformer that accounts for the difference between the actual 40 watts used and the "about 60" volt amps that your calculations shows were being consumed.

On Mon, 19 Nov 2012 11:57:16 -0600, "ps56k"
wrote:

I had to replace the burned out FL long straight tube in my shop light,
and noticed the marking indicated "40 watt".

I was thinking - our twist CFLs that replaced the our 60 watt bulbs
are only running about 14 real watts.

SO - are the traditional long straight tube FL shop lights actually using 40
watts,
or is that just and equiv and the real watt usage is much less, just like
the CFL ?

If not - then that means the long tube FL are as in-efficient as a normal
bulb.


As you can see from other replies, they may not be a true 40W, but
they will use more power than the CFL. What you want to com pare
though, is the light output to see if it is the same.

At work we replaced some 1000W light with brighter 128W fluorescent.