"J. Clarke" wrote:
If you have visions of becoming an electrical engineer, don't quit
your day
job.

For a resistive load P=E^2/R. If the lamp is rated for 100 watts at
130
volts then it will dissipate (120^2/130^2)*100 watts at 120v or
about 85
watts if its resistance remains constant.
---------------------------------------------
Review lamp data found in any lamp catalog.

The proof is left to the student.

Lew

Lew Hodgett wrote:
"J. Clarke" wrote:

And yet you don't know how to rerate an incandescent bulb. Just
goes to
show that he who has the best line of bull**** wins.

After you have had a chance to review a lamp catalog, get back to me.

And what do you believe that a lamp catalog will tell me? If you think that
it will tell me tht a lamp rated for 100 watts at 130 volts will draw 100
watts at 120 volts then you need to take remedial reading.

Lew Hodgett wrote:
"J. Clarke" wrote:
If you have visions of becoming an electrical engineer, don't quit
your day
job.

For a resistive load P=E^2/R. If the lamp is rated for 100 watts at
130
volts then it will dissipate (120^2/130^2)*100 watts at 120v or
about 85
watts if its resistance remains constant.
---------------------------------------------
Review lamp data found in any lamp catalog.

The proof is left to the student.

Proof? This is high school physics.

If you disagree please be kind enough to show us some support instead of
some vague "review a lamp catalog".

J. Clarke wrote:
Lew Hodgett wrote:
"J. Clarke" wrote:

If he's using 130v bulbs on 120v then he's using about 15% less KWH
than he
would be using 120v of the same nominal wattage.
-------------------------------------
NOT!

100 watts is 100 watts regardless the voltage rating of the lamp.

The current flowing thru the lamp is reduced which reduces lumen
output when the voltage rating of the lamp is increased.

(E = I*R for a resistance load.)

If you have visions of becoming an electrical engineer, don't quit your day
job.

For a resistive load P=E^2/R. If the lamp is rated for 100 watts at 130
volts then it will dissipate (120^2/130^2)*100 watts at 120v or about 85
watts if its resistance remains constant.

The assumption that the resistance will remain constant is a bad one. As has
already been pointed out elsewhere in this thread, the resistance of a light
bulb varies with the temperature of the filament. A colder filament will have
a lower resistance. A lower resistance will result in a higher current and
a higher power. The actual power at 120 volts will be somewhere between the
85 watts that you calculated and the 100 watts that it would dissipate at
130 volts.

J. Clarke wrote:
Lew Hodgett wrote:
"J. Clarke" wrote:

If he's using 130v bulbs on 120v then he's using about 15% less KWH
than he
would be using 120v of the same nominal wattage.
-------------------------------------
NOT!

100 watts is 100 watts regardless the voltage rating of the lamp.

The current flowing thru the lamp is reduced which reduces lumen
output when the voltage rating of the lamp is increased.

(E = I*R for a resistance load.)

If you have visions of becoming an electrical engineer, don't quit your day
job.

For a resistive load P=E^2/R. If the lamp is rated for 100 watts at 130
volts then it will dissipate (120^2/130^2)*100 watts at 120v or about 85
watts if its resistance remains constant.

The assumption that the resistance will remain constant is a bad one. As has
already been pointed out elsewhere in this thread, the resistance of a light
bulb varies with the temperature of the filament. A colder filament will have
a lower resistance. A lower resistance will result in a higher current and
a higher power. The actual power at 120 volts will be somewhere between the
85 watts that you calculated and the 100 watts that it would dissipate at
130 volts.

Dan Coby wrote:
J. Clarke wrote:
Lew Hodgett wrote:
"J. Clarke" wrote:

If he's using 130v bulbs on 120v then he's using about 15% less KWH
than he
would be using 120v of the same nominal wattage.
-------------------------------------
NOT!

100 watts is 100 watts regardless the voltage rating of the lamp.

The current flowing thru the lamp is reduced which reduces lumen
output when the voltage rating of the lamp is increased.

(E = I*R for a resistance load.)

If you have visions of becoming an electrical engineer, don't quit
your day job.

For a resistive load P=E^2/R. If the lamp is rated for 100 watts at
130 volts then it will dissipate (120^2/130^2)*100 watts at 120v or
about 85 watts if its resistance remains constant.

The assumption that the resistance will remain constant is a bad one.
As has already been pointed out elsewhere in this thread, the
resistance of a light bulb varies with the temperature of the
filament. A colder filament will have a lower resistance. A lower
resistance will result in a higher current and
a higher power. The actual power at 120 volts will be somewhere
between the 85 watts that you calculated and the 100 watts that it
would dissipate at 130 volts.

The standard number given is V^1.6. But the point is that a 100 watt bulb
only draws 100 watts at the design voltage, it's not 100 watts at all
voltages as Brainiac claims.

Lew Hodgett wrote:
"FrozenNorth" wrote:

Correct the bulbs resistance is fixed, increased voltage causes more
amperage, reduced voltage reduces the amperage. Light output and
bulb life will vary according to their ratings.
==============================================
NOT!!!

As the voltage rating of a specific wattage lamp rating increases, so
does the
resistance of the filament.

This increased filament resistance provides a mechanically heavier
wire which
then allows for a "rough service" or "traffic signal" lamp rating.

The increased filament resistance also reduces the current flowing
thru the filament
which in turn reduces the lumen output.

Basic data available in any lamp catalog.

Just some of the basic engineering trade offs the lamp designer faces.



Lew




Please explain *CLEARLY* how increasing the thickness of any uniform
substance can *increase* the resistance if everything else remains
unchanged.

Hint: imagine a square wire of a fixed length, double its thickness and
width, now explain to me the difference between that and four wires of
the original thickness in parallel for 1/4 the resistance!

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:

"dpb" wrote in message
...
Lew Hodgett wrote:
...

You are buying lumens, not hours of lamp life, so it becomes a trade off
of economy vs convenience.

No, I'm buying bulbs...or actually, not buying nearly as many bulbs as
would otherwise.

They output what they output (which if blown is nothing, nil, nada, until
replaced). _That's_ the tradeoff.

--



Yeahbut, you're not factoring in all of those extra lumens they provide at
the instant they burn out...

--

-Mike-

On Dec 10, 4:42*pm, "Lew Hodgett" wrote:
wrote:
In the US it's +/- 5%, ie. 114V to 126V.

Maybe that's in your utility area, but not the last two utilities
areas I've had.

No, that is the US standard.

On Dec 11, 1:12*am, IanM wrote:
Lew Hodgett wrote:
"FrozenNorth" wrote:

Correct the bulbs resistance is fixed, increased voltage causes more
amperage, reduced voltage reduces the amperage. *Light output and
bulb life will vary according to their ratings.
==============================================
NOT!!!

As the voltage rating of a specific wattage lamp rating increases, so
does the
resistance of the filament.

This increased filament resistance provides a mechanically heavier
wire which
then allows for a "rough service" or "traffic signal" lamp rating.

The increased filament resistance also reduces the current flowing
thru the filament
which in turn reduces the lumen output.

Basic data available in any lamp catalog.

Just some of the basic engineering trade offs the lamp designer faces.

Lew

Please explain *CLEARLY* how increasing the thickness of any uniform
substance can *increase* the resistance if everything else remains
unchanged.

Hint: imagine a square wire of a fixed length, double its thickness and
width, now explain to me the difference between that and four wires of
the original thickness in parallel for 1/4 the resistance!

Who said anything about a fixed length?

On Dec 10, 9:36*pm, "Martin H. Eastburn"
wrote:
We bought a new house once and the contractor put in 130v bulbs.
Not he 115v ones we buy in the store - and run them on 120 or 125v.

Anyway - when we sold the house 11 years later we still had some of
the original bulbs.

Consider : *P=E*I * If E drops - the power drops. *The bulb runs cooler.
* * * * * * *P=E^2/R *or R = E^2/P * 130*130/100 *= 13*13 = 269 ohms hot.
* * * * * * *(rule of thumb 1/10 of hot = cold resistance or 27 ohms for surges).
* * * * * * *I=P/E = 100/130 = .76 amps
* * Now - using the 130 bulb with 269 ohm filament and we run it at 120 :

* * * * * * * P (used) = 120*120/269 * *or 14400/269 = 53.53 watts.
* * * * * * * P=E*I * so I=P/E *I = 53/120 = .44 amps

You assume that the temparature, thus the resistance, of the filament
is the same at 130V as it is at 120V. This is certainly *not* true.
At 120V, the lower filament temperature not only will the bulb use
less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.

lower used wattage, longer life due to the derrating.

Much longer, yes. Bulb life is a function of something like the 16th
power of service voltage. It's still not saving money, unless there
is a cost associated with replacement in addition to the bulb cost.

On 2009-12-11, wrote:
On Dec 10, 9:36*pm, "Martin H. Eastburn"
wrote:
We bought a new house once and the contractor put in 130v bulbs.
Not he 115v ones we buy in the store - and run them on 120 or 125v.

Anyway - when we sold the house 11 years later we still had some of
the original bulbs.

Consider : *P=E*I * If E drops - the power drops. *The bulb runs cooler.
* * * * * * *P=E^2/R *or R = E^2/P * 130*130/100 *= 13*13 = 269 ohms hot.
* * * * * * *(rule of thumb 1/10 of hot = cold resistance or 27 ohms for surges).
* * * * * * *I=P/E = 100/130 = .76 amps
* * Now - using the 130 bulb with 269 ohm filament and we run it at 120 :

* * * * * * * P (used) = 120*120/269 * *or 14400/269 = 53.53 watts.
* * * * * * * P=E*I * so I=P/E *I = 53/120 = .44 amps

You assume that the temparature, thus the resistance, of the filament
is the same at 130V as it is at 120V. This is certainly *not* true.
At 120V, the lower filament temperature not only will the bulb use
less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.

lower used wattage, longer life due to the derrating.

Much longer, yes. Bulb life is a function of something like the 16th
power of service voltage. It's still not saving money, unless there
is a cost associated with replacement in addition to the bulb cost.



And the cost of replacement must be huge. 1000 hours of use of 100 W bulb is
going to use 100 kwh, I pay something like 11 eurocents per kwh so energy is
going to cost me something like 11 euros. Higher voltage filament bulbs
would easily cost several times more for same light output. I am moving to
led lights myself (not for energy efficiency, fluorecents are about same but
for longer life). Now testing this:
http://www.dealextreme.com/details.dx/sku.26514

seismo malm

wrote:
....

less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.
....

There's the same fallacy assumption that Lew made as well -- _ONLY_ if
one is requiring the same or more lumens will there be a higher energy
cost to obtain them--as told Lew, for household lighting, a 100W bulb is
a 100W bulb and one gets the light one gets (at least that's what I do).
It's good enough and bulbs last.

Sure it's not much for an ordinary 100W bulb so the convenience of not
having to replace them is a factor but there's no economic penalty
associated w/ gaining that (again, assuming one doesn't go from 75W _to_
100W per bulb).

--

On Dec 9, 1:36*pm, " wrote:
On Dec 9, 11:26*am, Hoosierpopi wrote:


Thank you. My sub-panel is in a barn 80 feet from the house panel. I
ran a solid copper (#8?) to the ground stake just outside where the
sub is mounted. The connection runs under ground (in HDPE pipe) along
with a 10Bast-T and a Coax.

On the suggestion (elsewhere): "Why not just take out the short 2 wire
cord and throw it away, and simply attach the long 3 wire to the saw?
"

I would say one needs to watch out that the longer "extension" cord is
of a suitable gauge as many tools come with a minimum gauge "pigtail"
which is "OK" if plugged directly into a suitable (amp-wise) outlet,
but not if run through one of those 16 gauge extension cords -
espeacially when they are twenty-five feet and more.

If you do re-wire with a longer cord, use at least 10 Gauge wire with
a ground (IMHO) to get the most power out of your tool. I use 20AMP
cords if "extending" to a Table Saw and the like. I've noticed severe
slowing down/loss of power when using lighter cords and the cord (esp
at plug end) get nice and toasty.





On Dec 8, 2:28*am, sibosop wrote:

I realize this isn't exactly a woodworking question, but when I asked
about 220 V wiring for my shed in an earlier thread a lot of
electricians came out of the 'woodwork'.

So. I now have 220 V in my shed for my Walker Turner table saw. I
noticed that the plug from the saw only has two wires. The ground is
not connected. *My shed has a ground stake.
Should I run the ground wire to the saw? It certainly has a whooping
iron chasis.
Should I not do this?

(For those of you who helped me the last time, I finally decided to
get an electrician to wire it. He took the 220V
line from my 30 amp circuit for the house drier (I have a gas drier,
so I don't use it), ran #10 wires out to a 30 amp
breaker panel in the shed, split out two 110V circuits and a 20 amp
220v and put in a ground stake. This took him
6 hours. It would have taken me about 2 months).

thanks,
b

My 220 consists of three leades, two "hot" and one "neutral" but the
newest setups (for household appliances 0 like a dryer) include a
separate equipment ground and use a four-conductor plug.

If you only have three leads, one is a ground not a neutral. *Often,
like older driers and range installations the ground is used as a
neutral, but as you note, this is no longer allowed. *Circuits like
air conditioners (and saws) that don't need a neutral can still use
three wire circuits but the third wire is a ground, not a neutral (it
carries no current). *Equipment grounds have been required for at
least fifty years.

As I understand it, a short in your saw could conceivably employ you
as the ground (wet shoes, damp floor and a short to the frame).

Which is why the equipment ground is a requirement. *There would be no
neutral current so a neutral conductor is not required.

I may be wrong, but I wire my 220VAC equipment with all four
conductors and do have a ground stake for the shop power distribution
box (about a 100 feet from the mains I ran it from at the house).

The *only* place neutral and ground may be (and must be) connected is
at the entrance panel. *Neutral and ground must be separated
everywhere else. *If your sub panel is separate from your entrance
panel it shouldn't have a separate ground stake, though perhaps it's
OK if a *large* enough ground wire connects the two. *I'm not sure
about this detail because it's easier to not have the ground stake at
the sub. *If there is a nearby lightning strike you want the house to
"ride the wave" (one ground point) not invite the current through your
house (two grounds).

On Fri, 11 Dec 2009 08:44:19 -0600, dpb wrote:

wrote:
...

less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.
...

There's the same fallacy assumption that Lew made as well -- _ONLY_ if
one is requiring the same or more lumens will there be a higher energy
cost to obtain them--as told Lew, for household lighting, a 100W bulb is
a 100W bulb and one gets the light one gets (at least that's what I do).
It's good enough and bulbs last.

Sure it's not much for an ordinary 100W bulb so the convenience of not
having to replace them is a factor but there's no economic penalty
associated w/ gaining that (again, assuming one doesn't go from 75W _to_
100W per bulb).


From GE 2006 large lamp catalog

100 A 130V 100 watts 750Hrs 1680 lumens
100A 130V@120V 89 watts 1950Hrs 1275 lumens GE shows rated watts as
89 at 120V.

Depends whether your more concerned about light level or life of the
lamp. Since there are so many better options these days it seems
pointles to even use them.

Mike M

On Dec 11, 8:44*am, dpb wrote:
wrote:

...

less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.

...

There's the same fallacy assumption that Lew made as well -- _ONLY_ if
one is requiring the same or more lumens will there be a higher energy
cost to obtain them--as told Lew, for household lighting, a 100W bulb is
a 100W bulb and one gets the light one gets (at least that's what I do).
* It's good enough and bulbs last.

No fallacy at all. Need less light? Use a lower wattage, or fewer
bulbs.

Sure it's not much for an ordinary 100W bulb so the convenience of not
having to replace them is a factor but there's no economic penalty
associated w/ gaining that (again, assuming one doesn't go from 75W _to_
100W per bulb).

That's a big assumption. The fact is that we use light to see.

On Dec 11, 9:49*am, Hoosierpopi wrote:
On Dec 9, 1:36*pm, " wrote:

On Dec 9, 11:26*am, Hoosierpopi wrote:

Thank you. My sub-panel is in a barn 80 feet from the house panel. I
ran a solid copper (#8?) to the ground stake just outside where the
sub is mounted. The connection runs under ground (in HDPE pipe) along
with a 10Bast-T and a Coax.

That's a different situation. It's not just a sub panel.

On the suggestion (elsewhere): "Why not just take out the short 2 wire
cord and throw it away, and simply attach the long 3 wire to the saw?
"

I would say one needs to watch out that the longer "extension" cord is
of a suitable gauge as many tools come with a minimum gauge "pigtail"
which is "OK" if plugged directly into a suitable (amp-wise) outlet,
but not if run through one of those 16 gauge extension cords -
espeacially when they are twenty-five feet and more.

Well, ya. Cords must be rated for the current drawn. 16ga is good
for 13A, IIRC. I think the only 16GA extension cords I own are used
only for lights. For (hand) saws I use only 12GA, even only 25'.

If you do re-wire with a longer cord, use at least 10 Gauge wire with
a ground (IMHO) to get the most power out of your tool. I use 20AMP
cords if "extending" to a Table Saw and the like. I've noticed severe
slowing down/loss of power when using lighter cords and the cord (esp
at plug end) get nice and toasty.

12GA is fine. It's no different than the wiring in the house. A foot
of 12GA in the wall is the same as a foot of extension. Yes, if the
total run is too long, half of it in 10GA will help. I replaced the
cord on my Unisaw with 15' of 12-3 SJ. There's probably 50' of 12-2 w/
G going back to the sub-panel from the wall. Changing the 15' from
12ga to 10ga isn't going to change anything. The saw starts with
authority now. ;-)

wrote:
....

That's a big assumption. The fact is that we use light to see.

Well, I can assert that in my case (the only one that actually matters
to me ) it's not an assumption at all. I see fine using the same
wattage-rated bulb in 130V version as the 120V and as long as that is so
it's a win if they last longer...

If you or another finds that isn't the case, you'll/they'll have to
handle it however you/they choose but that wouldn't negate my usage
patterns nor increase my cost (which was the erroneous claim being made).

--

IanM writes:

Please explain *CLEARLY* how increasing the thickness of any uniform
substance can *increase* the resistance if everything else remains
unchanged.


The resistance varies inversely to the cross-section of the conductor.

AWG 12 wire resistance/foot = 1.619Ohms.
AWG 10 wire resistance/foot = 1.018ohms.
AWG 8 0.6405

http://www.interfacebus.com/Copper_Wire_AWG_SIze.html

Ergo, heavier wire, less resistance.

So assume that a 100watt blub rated at 130V filament consumes
0.769231 amperes of current. From ohms law, one can then derive
the resistance of the conductor as (R=V/I) 156 ohms.

Now run that same bulb at 120volts, the current in the filament
(per again ohms law) will be (I=V/R) 0.769231 (i.e. the same current).

However, the power consumed (P=IV) will only be 92.3 watts, thus
reducing the lumen output of the bulb.

On Dec 11, 12:01*pm, dpb wrote:
wrote:

...

That's a big assumption. *The fact is that we use light to see.

Well, I can assert that in my case (the only one that actually matters
to me ) it's not an assumption at all. *I see fine using the same
wattage-rated bulb in 130V version as the 120V and as long as that is so
it's a win if they last longer...

Then why don't you use a 60W in stead of a 100W, for example?

If you or another finds that isn't the case, you'll/they'll have to
handle it however you/they choose but that wouldn't negate my usage
patterns nor increase my cost (which was the erroneous claim being made).

You're simply fooling yourself.

J. Clarke wrote:
Dan Coby wrote:
J. Clarke wrote:
....
For a resistive load P=E^2/R. If the lamp is rated for 100 watts at
130 volts then it will dissipate (120^2/130^2)*100 watts at 120v or
about 85 watts if its resistance remains constant.
The assumption that the resistance will remain constant is a bad one.
....
... The actual power at 120 volts will be somewhere
between the 85 watts that you calculated and the 100 watts that it
would dissipate at 130 volts.

The standard number given is V^1.6. But the point is that a 100 watt bulb
only draws 100 watts at the design voltage, it's not 100 watts at all
voltages as Brainiac claims.

I hadn't looked up specific numbers; I only used the fact that the power
actually used is what controls the operating cost and that bulbs are
rated for their power consumption at the stated voltage. Hence, the
variability between an ideal 120V and our typical higher voltage that is
still rarely as high as 130V will cause the power consumption to be less
than it would otherwise be albeit w/ a loss of lumens altho I really
don't think it's terribly noticeable unless the lighting already was
marginal.

Anyway, assuming the 1.6 exponent, the reduction factor would be 0.88
instead of 0.85 according to my trusty HP-97. In reality, altho I've
never monitored it for a period of time (altho come to think I do have
sufficient test gear I could; just never thought of doing so as doesn't
really make any difference as it is what it is and will continue to be
so) I'd guess our average would be around 124/125 based on the numbers I
generally have noted when did measure. So, would be less than that in
practice but it _won't_ be 1.0.

--

On Dec 11, 8:44*am, dpb wrote:
wrote:

...

less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.

...

There's the same fallacy assumption that Lew made as well -- _ONLY_ if
one is requiring the same or more lumens will there be a higher energy
cost to obtain them--as told Lew, for household lighting, a 100W bulb is
a 100W bulb and one gets the light one gets (at least that's what I do).
* It's good enough and bulbs last.

No a 100W bulb is *not* a 100W bulb. Look at the rated output of the
bulbs at the given voltage. You generally buy a light bulb for light
(lumens) not heat (watts). If you have excess light use a smaller
bulb.

Sure it's not much for an ordinary 100W bulb so the convenience of not
having to replace them is a factor but there's no economic penalty
associated w/ gaining that (again, assuming one doesn't go from 75W _to_
100W per bulb).

You assume that a 100W 130V bulb puts out *exactly* the light needed
and that no less will do. Bad assumption.

On 12/11/2009 01:24 PM, Lew Hodgett wrote:

For a given wattage of lamp, the total lamp resistance of the lamp
increases in direct proportion to the rated voltage.

I don't think this is correct.

Power = V^2/R

Based on that, to keep wattage constant resistance must increase as the
square of the voltage. Double the voltage and the resistance has to
increase by a factor of four.

Chris

"Martin H. Eastburn" wrote in message
...
They are called 'swinging transformers'

Funny, in the business we always called them tap changers, as did the power
companies that we dealt with (nation wide in the U.S.and parts of Canada).
When dealing with the manufacturers, they called them tap changers too. Glad
you straitened that out. We must have been wrong all these years. I'll have
to let them know.

wrote:
On Dec 11, 8:44 am, dpb wrote:
wrote:

...

less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.
...

There's the same fallacy assumption that Lew made as well -- _ONLY_ if
one is requiring the same or more lumens will there be a higher energy
cost to obtain them--as told Lew, for household lighting, a 100W bulb is
a 100W bulb and one gets the light one gets (at least that's what I do).
It's good enough and bulbs last.

No a 100W bulb is *not* a 100W bulb. Look at the rated output of the
bulbs at the given voltage. You generally buy a light bulb for light
(lumens) not heat (watts). If you have excess light use a smaller
bulb.

Sure it's not much for an ordinary 100W bulb so the convenience of not
having to replace them is a factor but there's no economic penalty
associated w/ gaining that (again, assuming one doesn't go from 75W _to_
100W per bulb).

You assume that a 100W 130V bulb puts out *exactly* the light needed
and that no less will do. Bad assumption.

I don't "assume" anything about "exactly" anything the light output.
It puts out what it puts out and that's adequate w/ a 130V bulb just
as it is w/ a 120V of the same wattage even though it would be somewhat
more w/ the latter. _IF_ it weren't, I'd have to either bump in size or
go back to 120V or add another light. I'm simply saying given the
lights we have and our habits _we've_ not seen any necessity to do any
of the above.

OTOH, you're the one that apparently is obsessed w/ somebody not doing
as you would do and measuring lumens to the nth degree.

Under the above scenario, it's cheaper as the power dissipated will be
less for the 130V bulb at something under 130V average than it will for
the same rated 120V bulb at the same average 120V. Add onto that the
much longer lifetime and it's "win-win".

Again, if you want to do something different; fine. Just don't claim
I'm spending more in absolute $$ running 130V bulbs of the same size and
you certainly aren't in position to state I don't have adequate lighting
near my easy chair or not to meet my needs.

Finis, you can tilt at light bulbs all you want, I'm done here.

--

wrote:
On Dec 11, 12:01 pm, dpb wrote:
wrote:

...

That's a big assumption. The fact is that we use light to see.
Well, I can assert that in my case (the only one that actually matters
to me ) it's not an assumption at all. I see fine using the same
wattage-rated bulb in 130V version as the 120V and as long as that is so
it's a win if they last longer...

Then why don't you use a 60W in stead of a 100W, for example?

Because the difference in a 60W @120V wouldn't be enough for a location
that has a 100W in it, either. The substitution is as earlier
stated--simply 130V of whatever I'd use 120V in that location and I'm
good to go.

If you or another finds that isn't the case, you'll/they'll have to
handle it however you/they choose but that wouldn't negate my usage
patterns nor increase my cost (which was the erroneous claim being made).

You're simply fooling yourself.

No, you're simply trying to make an argument that doesn't hold by making
a false requirement that isn't pertinent. IOW, the strawman argument;
if you change the groundrules to suit your purposes you can "win" but it
doesn't negate the conclusions of the original premise at all.

--

Scott Lurndal wrote:
IanM writes:

Please explain *CLEARLY* how increasing the thickness of any uniform
substance can *increase* the resistance if everything else remains
unchanged.


The resistance varies inversely to the cross-section of the conductor.

AWG 12 wire resistance/foot = 1.619Ohms.
AWG 10 wire resistance/foot = 1.018ohms.
AWG 8 0.6405

http://www.interfacebus.com/Copper_Wire_AWG_SIze.html

Actually those number are ohms per 1000 feet.


Ergo, heavier wire, less resistance.

Yes. assuming the same length, material, etc.


So assume that a 100watt blub rated at 130V filament consumes
0.769231 amperes of current. From ohms law, one can then derive
the resistance of the conductor as (R=V/I) 156 ohms.

No. The resistance should be 169 ohms at 130 volts. You seem to have
gotten 156 ohms by dividing 120 volts by 0.768231 amps. There is no
justification for this. The resistance of the filament will vary with
its temperature. It will be lower than 169 ohms at 120 volts. but
there is no reason to assume that it will be 156 ohms.


Now run that same bulb at 120volts, the current in the filament
(per again ohms law) will be (I=V/R) 0.769231 (i.e. the same current).

See previous comment. You seem to have derived a result from your
assumptions (you assumed the current at 120 volts is 0.769231 amps
in your previous calculation).


However, the power consumed (P=IV) will only be 92.3 watts, thus
reducing the lumen output of the bulb.

This result is based upon an incorrect assumption that the current is
0.7629231 when the voltage is 120 volts.

The power at 120 volts will be between the 85 watts (the value that would
be calculated if the resistance is constant with temperature) and the 100
watts at 130 volts. Thus 92.3 watts is a reasonable guess for the power
at 120 volts but you have not presented anything to prove it.


Dan

In article ,
J. Clarke wrote:
Lew Hodgett wrote:
"dpb" wrote:

No, I'm buying bulbs...or actually, not buying nearly as many bulbs
as would otherwise.

Actually you are buying both lamps and KWH to operate them.

If you wish to buy more KWH than are needed for the sake of
convenience, that's your choice.

If he's using 130v bulbs on 120v then he's using about 15% less KWH than he
would be using 120v of the same nominal wattage. If that gives him enough
light then he's got no problem. If he has to add bulbs or go up a wattage
level to get the illumination level he needs then things get more
complicated.



By using 130V bulbs on 120 V, he's paying *MORE*PER*LUMEN* for the electricity
to operate them, vs a 120V rated bulb.

Generally people thing of a light bulb as 'a light bulb', with little regard
to how much light it puts out. This leads to ill-informed decisions about the
cost-effectiveness of various alternatives.

The _first_ thing one has to do, is figure out how much _light_ is needed
and/or desirable, then look for the 'least cost' way of getting that amount
of light. Higher wattage bulbs produce more light output _per_watt_ than
low wattage ones. Thus, a few higher wattage bulbs will produce more light
than an equivalent wattage of low-wattage bulbs.

The true 'cost of ownership' of light bulbs depends on the cost of the
bulb, the frequency with which it has to be replaced, the 'cost' (labor,
etc) in performing the replacement, _and_ the 'operating cost' (the
electricity to drive it).

The cost of the electricity -- over the lifetime of the bulb -- generally
swamps the cost of the bulb itself.

The frequency of replacement determines how much of a factor the 'cost of
replacement' is. Depending on circumstances, this can be a 'small change'
item, or it can be far more than the bulb _and_ the electricity to run it.

"Chris Friesen" wrote:

I don't think this is correct.

You are correct.

Power = V^2/R

Yep.

Lew

In article ,
dpb wrote:

[[.. sneck ..]]

Interesting that Lew would point this out in a followup post that a
higher-cost bulb pays for itself even at lower power cost but can't help
but try to make a putdown to the logic of using a 130V to obtain the
same benefit.

Substituting a standard 130V bulb for a standard 120V one probably does *NOT*
pay for itself -- *IF* you need the same light output as the 120V bulb gives.

Running a bulb at lower than the 'rated' voltage, _does_ extend the life of
the bulb, *BUT* the quantity of light output (the 'lumens') goes down even
_faster_ than the savings in electricity. Thus the 'cost per lumen' of the
eletricity is _higher_ usuwing the 130V bulb at 120v, vs the 120v bulb.

It is also a fact that the cost of electricity over the life of the bulb
swamps the cost of the bulb itself.

That said, there are "much more efficient" technologies for lighting than
'incandescent', e.g. 'halogen'. These technologies have a _much_ higher
lumen output _per_watt_of_power_consumed_ than conventional incandescents.
Thus, you can get the same _light_ output, for far less power consumed.
Amortized over the rated life of the bulb, the power savings _greatly_
exceed the cost of the 'high-priced' bulb required to achieve the savings.o

Running the _same_ technology (incandescent) in a down-graded form (130V bulb
at 120V) does *not* achieve these savings. In fact, because the bulb is being
operated in a 'less than optimum' (relative to _design_ criteria) manner, the
cost _per_lumen_output_ is higher than the optimal operation.

In article ,
wrote:
On Dec 10, 9:36*pm, "Martin H. Eastburn"
wrote:
We bought a new house once and the contractor put in 130v bulbs.
Not he 115v ones we buy in the store - and run them on 120 or 125v.

Anyway - when we sold the house 11 years later we still had some of
the original bulbs.

Consider : *P=E*I * If E drops - the power drops. *The bulb runs cooler.
* * * * * * *P=E^2/R *or R = E^2/P * 130*130/100 *= 13*13 = 269 ohms hot.
* * * * * * *(rule of thumb 1/10 of hot = cold resistance or 27 ohms for
surges).
* * * * * * *I=P/E = 100/130 = .76 amps
* * Now - using the 130 bulb with 269 ohm filament and we run it at 120 :

* * * * * * * P (used) = 120*120/269 * *or 14400/269 = 53.53 watts.
* * * * * * * P=E*I * so I=P/E *I = 53/120 = .44 amps

You assume that the temparature, thus the resistance, of the filament
is the same at 130V as it is at 120V. This is certainly *not* true.
At 120V, the lower filament temperature not only will the bulb use
less power (though less than expected using your calculations) will
make the bulb less efficient (lumens per watt), costing you money too.

lower used wattage, longer life due to the derrating.

Much longer, yes. Bulb life is a function of something like the 16th
power of service voltage.

Eleventh power. not 16th. grin
a 5% decrease in voltage equates to an over 70% increase in bulb life.


It's still not saving money, unless there
is a cost associated with replacement in addition to the bulb cost.


Depends on what you're measuring. grin

"Per lumen of light output", the de-rated bulb is more expensive to operate.

If the de-rated output is 'adequate', and you're just looking at the cost of
operating "a bulb", the 130V bulb does save a little (circa 10%) operating
money. Plus a little more for the reduced replacement frequency. The only
_real_ advantage comes if the bulb is located somewhere where it is _hard_
to change -- i.e., with a significant 'labor' cost involved in performing
the replacement.

In article ,
dpb wrote:
wrote:
On Dec 11, 12:01 pm, dpb wrote:
wrote:

...

That's a big assumption. The fact is that we use light to see.
Well, I can assert that in my case (the only one that actually matters
to me ) it's not an assumption at all. I see fine using the same
wattage-rated bulb in 130V version as the 120V and as long as that is so
it's a win if they last longer...

Then why don't you use a 60W in stead of a 100W, for example?

Because the difference in a 60W @120V wouldn't be enough for a location
that has a 100W in it, either. The substitution is as earlier
stated--simply 130V of whatever I'd use 120V in that location and I'm
good to go.

A 100 W 130V bulb operated at 120V has just about the same output as a 75W 120V
bulb. It's a wash on electricity cost, balanced against the cost difference
for the 130V bulbs, vs 120V ones. Plus the "convenience factor" of less
frequent bulb replacement. Drawback: the 130V bulbs give off a "yellower"
light than the 120V ones -- one may, or may not, notice it.

A 60W 120V bulb has somewhat more output than a 75W 130V bulb at 120V.
The 120v bulb is the _clear_ winner in this case. bulb is less expensive,
gives off more light, and uses less electricity. The -only- advantage to
the 130V bulb is less-frequent replacement.

At lower wattages (60W@130/40W@120 and 40W@130/25W@120), the cost advantage
also goes to the rated 120V bulb. Again, the -only- advantage to the 130V
bulb is less-frequent replacement.

What has gone unsaid is that a yellowish bulb gives the subliminal
impression of warmth. By dropping the voltage across the lamp
filament, you can fool the building occupants into turning down
the thermostat in the winter. This saves on heating oil, gas,
coal or electricity. Thus, it's obvious: a diode or series
wiring saves energy during cold weather. During the summer, just
boost the voltage up a tad and they'll be turning off the A/C and
putting on sweaters.

grin Please send all flames and men in white coats to someone
else.

--
Nonny

ELOQUIDIOT (n) A highly educated, sophisticated,
and articulate person who has absolutely no clue
concerning what they are talking about.
The person is typically a media commentator or politician.

"Robert Bonomi" wrote in message

Since there's been a lot of great thought posted here about
voltage, resistance, light output and longevity, I thought I'd go
ahead and give a general explanation of electricity for those of
you all who don't really understand it fully. It's a repeat of a
post to another newsgroup, but of equal relevance here. Grin

Electricity explained
I think its time for me to explain about 220 current and why it is
so
different from 110 volt service. First of all, it's twice as big.
Secondly,
it'll shock you more. Outside of that, 220 is really two 110 volt
lines
coming to your house from different parts of the globe. The up and
down 110
comes from the northern hemisphere, and the down and up version
comes from
below the equator.
Without trying to get technical, it all boils down to the
direction water
flows when it goes down the drain. On the top of the earth, it
goes
clockwise, while on the bottom of the earth it goes counter
clockwise. Since
most electricity is made from hydro dams, the clockwise flow gives
you an up
and down sine wave, while the counterclockwise version gives you a
down and
up sine wave. Between the two, you have 220 volts, while either
individual
side only gives you 110 volts.
This is particularly important to know when buying power tools-
which side
of the globe did they come from? If you get an Australian saw, for
instance, it
will turn backwards if connected to a US generated 110 volt
source. Sure,
you can buy backwards blades for it, but that is an unnecessary
burden.
Other appliances, like toasters cannot be converted from
Australian
electricity to American electricity, with horrible results. I knew
one
person who bought an Australian toaster by mistake and it froze
the slices
of bread she put in it.
If you wire your shop with 220 and accidentally get two
US-generated 110
volt lines run in by accident, you can get 220 by using a trick I
learned
from an old electrician. Just put each source into its own fuse
box and then
turn one of the boxes upside down. That'll invert one of the two
up and down
sine waves to down and up, giving you 220. DO NOT just turn the
box
sideways, since that'll give you 165 volts and you'll be limited
to just
using Canadian tools with it.

--
Nonny

ELOQUIDIOT (n) A highly educated, sophisticated,
and articulate person who has absolutely no clue
concerning what they are talking about.
The person is typically a media commentator or politician.

Nonny wrote:

Electricity explained
I think its time for me to explain about 220 current and why it is so
different from 110 volt service. First of all, it's twice as big. Secondly,
it'll shock you more. Outside of that, 220 is really two 110 volt lines
coming to your house from different parts of the globe. The up and down 110
comes from the northern hemisphere, and the down and up version comes from
below the equator.
Without trying to get technical, it all boils down to the direction water
flows when it goes down the drain. On the top of the earth, it goes
clockwise, while on the bottom of the earth it goes counter clockwise.
Since
most electricity is made from hydro dams, the clockwise flow gives you
an up
and down sine wave, while the counterclockwise version gives you a down and
up sine wave. Between the two, you have 220 volts, while either individual
side only gives you 110 volts.
This is particularly important to know when buying power tools- which side
of the globe did they come from? If you get an Australian saw, for
instance, it
will turn backwards if connected to a US generated 110 volt source. Sure,
you can buy backwards blades for it, but that is an unnecessary burden.
Other appliances, like toasters cannot be converted from Australian
electricity to American electricity, with horrible results. I knew one
person who bought an Australian toaster by mistake and it froze the slices
of bread she put in it.
If you wire your shop with 220 and accidentally get two US-generated 110
volt lines run in by accident, you can get 220 by using a trick I learned
from an old electrician. Just put each source into its own fuse box and
then
turn one of the boxes upside down. That'll invert one of the two up and
down
sine waves to down and up, giving you 220. DO NOT just turn the box
sideways, since that'll give you 165 volts and you'll be limited to just
using Canadian tools with it.

ROTFL! ... should be in the Anti-FAQ.

--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

Nonny wrote:

"Robert Bonomi" wrote in message

Since there's been a lot of great thought posted here about voltage,
resistance, light output and longevity, I thought I'd go ahead and give
a general explanation of electricity for those of you all who don't
really understand it fully. It's a repeat of a post to another
newsgroup, but of equal relevance here. Grin

Electricity explained
I think its time for me to explain about 220 current and why it is so
different from 110 volt service. First of all, it's twice as big. Secondly,
it'll shock you more. Outside of that, 220 is really two 110 volt lines
coming to your house from different parts of the globe. The up and down 110
comes from the northern hemisphere, and the down and up version comes from
below the equator.
Without trying to get technical, it all boils down to the direction water
flows when it goes down the drain. On the top of the earth, it goes
clockwise, while on the bottom of the earth it goes counter clockwise.
Since
most electricity is made from hydro dams, the clockwise flow gives you
an up
and down sine wave, while the counterclockwise version gives you a down and
up sine wave. Between the two, you have 220 volts, while either individual
side only gives you 110 volts.
This is particularly important to know when buying power tools- which side
of the globe did they come from? If you get an Australian saw, for
instance, it
will turn backwards if connected to a US generated 110 volt source. Sure,
you can buy backwards blades for it, but that is an unnecessary burden.
Other appliances, like toasters cannot be converted from Australian
electricity to American electricity, with horrible results. I knew one
person who bought an Australian toaster by mistake and it froze the slices
of bread she put in it.
If you wire your shop with 220 and accidentally get two US-generated 110
volt lines run in by accident, you can get 220 by using a trick I learned
from an old electrician. Just put each source into its own fuse box and
then
turn one of the boxes upside down. That'll invert one of the two up and
down
sine waves to down and up, giving you 220. DO NOT just turn the box
sideways, since that'll give you 165 volts and you'll be limited to just
using Canadian tools with it.

My sinuses haven't been this clear in days... wow.
:-0

"jo4hn" wrote in message
m...
Nonny wrote:

"Robert Bonomi" wrote in message

Since there's been a lot of great thought posted here about voltage,
resistance, light output and longevity, I thought I'd go ahead and give a
general explanation of electricity for those of you all who don't really
understand it fully. It's a repeat of a post to another newsgroup, but
of equal relevance here. Grin

Electricity explained
I think its time for me to explain about 220 current and why it is so
different from 110 volt service. First of all, it's twice as big.
Secondly,
it'll shock you more. Outside of that, 220 is really two 110 volt lines
coming to your house from different parts of the globe. The up and down
110
comes from the northern hemisphere, and the down and up version comes
from
below the equator.
Without trying to get technical, it all boils down to the direction water
flows when it goes down the drain. On the top of the earth, it goes
clockwise, while on the bottom of the earth it goes counter clockwise.
Since
most electricity is made from hydro dams, the clockwise flow gives you an
up
and down sine wave, while the counterclockwise version gives you a down
and
up sine wave. Between the two, you have 220 volts, while either
individual
side only gives you 110 volts.
This is particularly important to know when buying power tools- which
side
of the globe did they come from? If you get an Australian saw, for
instance, it
will turn backwards if connected to a US generated 110 volt source. Sure,
you can buy backwards blades for it, but that is an unnecessary burden.
Other appliances, like toasters cannot be converted from Australian
electricity to American electricity, with horrible results. I knew one
person who bought an Australian toaster by mistake and it froze the
slices
of bread she put in it.
If you wire your shop with 220 and accidentally get two US-generated 110
volt lines run in by accident, you can get 220 by using a trick I learned
from an old electrician. Just put each source into its own fuse box and
then
turn one of the boxes upside down. That'll invert one of the two up and
down
sine waves to down and up, giving you 220. DO NOT just turn the box
sideways, since that'll give you 165 volts and you'll be limited to just
using Canadian tools with it.

Robert,
You know that's a bunch of bull. If you have an Australian saw and it runs
backwards all you have to do is to mount the blade backwards.
Sheesh.

Max

"Nonny" wrote in message
...

"Robert Bonomi" wrote in message

Since there's been a lot of great thought posted here about voltage,
resistance, light output and longevity, I thought I'd go ahead and give a
general explanation of electricity for those of you all who don't really
understand it fully. It's a repeat of a post to another newsgroup, but of
equal relevance here. Grin

Electricity explained
I think its time for me to explain about 220 current and why it is so
different from 110 volt service. First of all, it's twice as big.
Secondly,
it'll shock you more. Outside of that, 220 is really two 110 volt lines
coming to your house from different parts of the globe. The up and down
110
comes from the northern hemisphere, and the down and up version comes from
below the equator.
Without trying to get technical, it all boils down to the direction water
flows when it goes down the drain. On the top of the earth, it goes
clockwise, while on the bottom of the earth it goes counter clockwise.
Since
most electricity is made from hydro dams, the clockwise flow gives you an
up
and down sine wave, while the counterclockwise version gives you a down
and
up sine wave. Between the two, you have 220 volts, while either individual
side only gives you 110 volts.
This is particularly important to know when buying power tools- which side
of the globe did they come from? If you get an Australian saw, for
instance, it
will turn backwards if connected to a US generated 110 volt source. Sure,
you can buy backwards blades for it, but that is an unnecessary burden.
Other appliances, like toasters cannot be converted from Australian
electricity to American electricity, with horrible results. I knew one
person who bought an Australian toaster by mistake and it froze the slices
of bread she put in it.
If you wire your shop with 220 and accidentally get two US-generated 110
volt lines run in by accident, you can get 220 by using a trick I learned
from an old electrician. Just put each source into its own fuse box and
then
turn one of the boxes upside down. That'll invert one of the two up and
down
sine waves to down and up, giving you 220. DO NOT just turn the box
sideways, since that'll give you 165 volts and you'll be limited to just


Finally! An authoritative explanation of all those things that have been so
confusing for so long!

--

-Mike-

On Dec 11, 11:50*am, " wrote:

12GA is fine. .... The saw starts with authority now. *;-)

Wouldn't doubt it. I do go overboard with my wiring at times. Well,
most times. But I did only run three 8's and a ground to the shop.
Reading here, I probably should have gone with 6GA to be as bullet
proof!

On Fri, 11 Dec 2009 16:40:43 -0600, the infamous
(Robert Bonomi) scrawled the following:

In article ,
dpb wrote:
wrote:
On Dec 11, 12:01 pm, dpb wrote:
wrote:

...

That's a big assumption. The fact is that we use light to see.
Well, I can assert that in my case (the only one that actually matters
to me ) it's not an assumption at all. I see fine using the same
wattage-rated bulb in 130V version as the 120V and as long as that is so
it's a win if they last longer...

Then why don't you use a 60W in stead of a 100W, for example?

Because the difference in a 60W @120V wouldn't be enough for a location
that has a 100W in it, either. The substitution is as earlier
stated--simply 130V of whatever I'd use 120V in that location and I'm
good to go.

A 100 W 130V bulb operated at 120V has just about the same output as a 75W 120V
bulb. It's a wash on electricity cost, balanced against the cost difference
for the 130V bulbs, vs 120V ones. Plus the "convenience factor" of less
frequent bulb replacement. Drawback: the 130V bulbs give off a "yellower"
light than the 120V ones -- one may, or may not, notice it.

A 60W 120V bulb has somewhat more output than a 75W 130V bulb at 120V.
The 120v bulb is the _clear_ winner in this case. bulb is less expensive,
gives off more light, and uses less electricity. The -only- advantage to
the 130V bulb is less-frequent replacement.

At lower wattages (60W@130/40W@120 and 40W@130/25W@120), the cost advantage
also goes to the rated 120V bulb. Again, the -only- advantage to the 130V
bulb is less-frequent replacement.

Why don't ALL OF YOU stop wasting electricity and get rid of the
ghastly yellow lighting at the same time? CFLs are the way to go.
http://fwd4.me/83K ULA lights have worked well for me so far, and I
bought a dozen. They're a nice cool white. Whatever you do, don't buy
Lights of America brand which Homey's Despot used to sell. I had
HORRIBLE experiences with their cheap crap.

My electric bill last month was $18 and change. The only incans I have
in the house are in the fridge, stove (no replacements available for
the two previous lamps), laundry room (130v Rough Service which was
here when I moved in and refuses to die), and a pair of Reveal bulbs
in the security light outside.

--
Don't forget the 7 P's:
Proper Prior Planning Prevents ****-Poor Performance