130V lamps

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RUWired

Senior Member
Location
Pa.
Pro;lamps should last a little longer on nominal 120 volt circuit.
Con;not quite as bright.
pro;A typical 100w 130v lamp would use 85w's at 120v.
con;might cost a little more.
Rick
 

eric stromberg

Senior Member
Location
Texas
The colour will be slightly shifted to the yellow-orange side of the spectrum.

This is why a 100 Watt bulb, turned down to 25 Watts by a dimmer will have a different colour than a 25 Watt bulb at full voltage.

This is also why, the old Photoflood bulbs only lasted about 4 hours. In order to get the bluer colour to match daylight, the filament had to be purposely over-voltaged (is this a word?). This significantly reduced the life of the bulb.

Eric Stromberg, P.E.
 

eric stromberg

Senior Member
Location
Texas
Hardworking,
I grew up on a military base in Germany. My father was an army doctor.

I spent 4 years, or so, writing application software on top of an English 3D database engine. I just can't seem to get the 'ou' out of my brain. You'll be pleased to know, however, that i drive a pick-up truck, not a lorry. :D

Eric
 

rattus

Senior Member
Also, the efficiency of an incandescent lamp falls as the applied voltage is reduced. I use them in trouble lights instead of the overpriced rough service lamps.
 

don_resqcapt19

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Location
Illinois
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retired electrician
Larry,
85 is correct, the wattage changes with the square of the change in voltage. If you square your answer, you will get the 85 watts.
Don
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
don_resqcapt19 said:
Larry,
85 is correct, the wattage changes with the square of the change in voltage. If you square your answer, you will get the 85 watts.
Don

Don,

Could you go into a little more detail?

E=IR
W=EI

If R remains constant, and E goes down, it would seem W would go down proportionally.

Edit, DUH! if E goes down, so does I. Think Lou, before you post!
:?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
What about light output? I seem to remember as a rule of thumb that a 100 watt, 130 volt lamp used at 120 volts has the approximately the same number of lumens as a 75 watt, 120 volt lamp operating at 120 volts or about a 25% reduction in light output.
 

coulter

Senior Member
]
don_resqcapt19 said:
... the wattage changes with the square of the change in voltage....
hardworkingstiff said:
... If R remains constant, ...

Help me out here. I didn't think incandesant bulbs were linear - R is not constant, but temperature dependent. A 10% voltage reduction does not give a 10% current reduction.

carl
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
Carl,

I think resistance stays the same (or very close), it just gets hotter and hotter (and glows more, more light) with higher voltage (and more amps).

There might be some resistance change (minimal I believe) with heating.

Others more knowledgeable will correct me if I'm wrong.
 

Onitram

Member
bulb resistance

bulb resistance

In the real world, like light bulbs, loads are affected by the current
flowing through them. The tungsten lamp filament like many materials has
a positive temperature coefficient. As it gets hot it's resistance
increases. Ohm's law does not take that into account. There are other
formulations that do.
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
Re: bulb resistance

Re: bulb resistance

Onitram said:
In the real world, like light bulbs, loads are affected by the current
flowing through them. The tungsten lamp filament like many materials has
a positive temperature coefficient. As it gets hot it's resistance
increases. Ohm's law does not take that into account. There are other
formulations that do.

Ok, can you tell/show us the effect (on the resistance) of using 130-volt lamps with a 120-volt source? I am curious as to how much of an effect the temperature change has on the resistance.
 

Onitram

Member
Standard household voltage in this country is between 110 and 120 volts. So, "Why," you might ask, "would someone rate a bulb at 130 volts?".

A bulb that says it's 100 watts, but if you read the fine print it only achieves this output at 130 volts. Thus, in the reality of your 120 volt home, you only get a 92 watt bulb. What's worse, since the light is effectively dimmed, it glows slightly orange instead of white as a bulb would at it's rated voltage. I found out 130 volts bulb last longer!! as it wil
not get as hot. resistence does increase not much ,bulbs sre designed, i will locate the formulasand post here, you raise the voltage and current go up.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
A bulb that says it's 100 watts, but if you read the fine print it only achieves this output at 130 volts.


This is only true if it's a 130 volt lamp. Most standard lamps are designed for 120 volts and their energy consumption (in watts) and light output (in lumens) is based on 120 volts.


There is a chart on page 10 of this link that shows the relationship between voltage, wattage, light output, and lamp life:


http://dafnwebpd.sylvania.com/os_fi...dth=600&hgth=450&Desc=Incandescent Technology
 

beanland

Senior Member
Location
Vancouver, WA
Life, Lumens, Watts

Life, Lumens, Watts

A 100W, 750 hour, 2700 lumen, 130V lamp will burn for 2200 hr at 2000 lumens using 88 watts. You get less light, less efficiency, but longer life. 130V lamps are great where access to the bulb is difficult.

By the way, a 240V 750Hr lamp will last 700 years if operated at 120V! But you don't get much light.
 

coulter

Senior Member
Re: Life, Lumens, Watts

Re: Life, Lumens, Watts

beanland said:
... a 240V 750Hr lamp will last 700 years if operated at 120V! But you don't get much light.

I have seen that used in lights on high towers - literally. I suspect they are using LEDs now.

carl
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
lamps

lamps

By the way, a 240V 750Hr lamp will last 700 years if operated at 120V! But you don't get much light
stupid premature lamp failure! I had a 240v, 40 watt lamp operating 24/7 on a 120v circuit and it only lasted 8 years
 
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