In article , CJT wrote: (edited slightly)
Nate Nagel wrote:
wrote:
On 19 Jan 09 19:23:56 -0600, AZ Nomad said:
On 19 Jan 2009 15:59:38 -0500, wrote:
The ceiling fixtures in our house all have labels indicating the
maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
of course it is. Do you think the actual light causes the fixture
to catch fire?
Although heat may and probably is the issue, over wattage through
current draw certainly could become a problem.
A bulb that draws 25W to produce the light of a 75W incadescent bulb
isn't going to overtax a fixture designed for 75W.
Correct you are, but what happens to a fixture that is rated for a 100
watt incandescent bulb when you use it for something other than
lighting? Are you saying that as long as you don't develop 100 watts
of heat then the fixture will be just fine?
Yes, so long as you aren't actually drawing more than 100W.
I think perhaps his point is how the power factor can affect the current
vs watt relationship.
My experience so far is that even with lower power factor, CFLs
usually draw less current and VA than incandescents of same light output.
And in the few cases when they draw more, they don't draw much more. And
my experience so far is that no spiral CFLs draw more current and VA than
"equivalent incandescent" despite lower power factor.
And in case anyone wonders about VA and amps being billed or amounting
to fuel consumption - only "real watts" get billed, and current other than
that associated with "real watts" has much less contribution to fuel
consumption for generators than "real watts" do.
The reactive and harmonic amps merely increase wire and transformer and
generator winding heating (that loss causes a minor increase in fuel
consumption, small compared to that needed to deliver same extra amps to
resistive loads), maybe also vibration in the generators. Power companies
bitch about power factor mainly out of need to accomodate amps not
resulting in billable watts, and they often surcharge commercial and
industrial customers (not residential ones) for power factor of a customer
as a whole falling below .8. The issue is wire and transformers carrying
amps not associated with billable watts or watt-hours.
Replacing a 60 watt incandescent with a CFL of wattage 13 to 19 watts
will reduce coal burning even if both draw the same amps.
- Don Klipstein )