Joule Lamp

[Lynxsteam]

Welcome Sea Monkey.  Thanks for the wiki link.  I learn something every day at least.

B-rads, that is very cool.  I will admit, when power goes out at my house I start the whole house gas generator and it is noisy!  I shut it off at night and we have no lights so we use candles, flashlights, oil lamps to get to bed.  This is a great option now to have a quiet source of whole room lighting where we need it. 

Did you get the last thing hooked up before the power came back on?  I bet you were busy.  That's what good husbands do.

[JouleSeeker]

The weirdest thing!

My watt meter, which I have used often and I trust, doesn't register CFLs or LEDs correctly.  But correctly with a DMM amp setting?

For a 14 watt CFL I get 40 watts on the watt meter, with an amp meter I get .115 amps x 120 volts = 13.8 watts
For the Utilitech Pro 7.5 I get 16 watts on the watt meter, but .072 amps X 120 v = 8.64 watts
For the Phillips 3 watt LED I get 8.4 watts on the watt meter, but .022 amps x 120 v =2.64 watts
For a 40 watt incandescent I get 37 watts on the watt meter, but .315 amps x 120  v = 37.8 watts  close to the same!
For a 60 watt incandescent I get 59 watts on the watt meter, but .502 x 120 v = 60.24 watts close to the same

So why does the watt meter register motors, incandescent and the toaster correctly but not CFLs or LEDs?  Does the circuitry in these bulbs mess with the inductive sensor on the Watt meter?

Our power was out this morning -- I can sympathize, b-rads.

@Lynx -- I tested an LED bulb and a CFL bulb with TWO watt-meters and also compared with V*I (current determined by a clamp-on ammeter).  Everything looking in agreement here:


For a 13 watt CFL I get 15.3 watts on the watt meter, with the clamp-on amp meter I get .12 amps x 123 volts = 15.7 watts; decent agreement within measurement uncertainties.
For the Utilitech Pro 7.5 I get 8.0 watts on the watt meter, and 0.06(5) amps X 123 v = 8 watts.

I'd check your watt-meter.  Note (photo) that I used two watt-meters, one plugged into the other, so I check one against the other. 

[kooler]

hello,
jouleseeker isn't the clamp meter suppose to be on the black wire.
good work everyone..

[NickZ]

   @ Sea Monkey, & Kooler:
   Good to see both you guys here, also.  Been missing your low draw your circuits lately Kooler. Hope that your health is ok, now.
                                                     
   NickZ
                                             

[JouleSeeker]

@kooler --  the white wire is the "return" wire in this case.  I checked -- both wires (black and white) carry the same current, as one would expect.  With two LED bulbs, I just measured 0.14A on the black wire (and on the white wire, same) at 122 V = 122 x 0.14 = 17 W, and I get the same reading on the watt-meter, that is, same within small measurement errors.