Kilowatt hour meter calibration

[Rubycon]

The spinning disk in a traditional kilowatt hour meter has numbers and graduations on its top. Do they use these to calibrate the meters? If one had the formula would it be safe to say that with a strobotach one could obtain an accurate reading of power flow through the meter socket?

 

[CycloWizard]

I would think they would have to use them to calibrate the meter. Either that, or they are just ripping you off and not calibrating anything. You should definitely be able to read it out if you can determine the formula, which shouldn't be hard. Just track some observations of the disk position and the change in meter reading and you should be able to determine the relationship.

 

[dkozloski]

If there is some question about the calibration of your electric power meter a simple call to your utility company will bring them out with an exchange meter. The local company has trained technicians that take care of this. Their operation is regulated by the state weights and measures department.

 

[Rubycon]

Originally posted by: dkozloski
If there is some question about the calibration of your electric power meter a simple call to your utility company will bring them out with an exchange meter. The local company has trained technicians that take care of this. Their operation is regulated by the state weights and measures department.

No that does not apply to me but I was just wondering if n speed = 600w will 2n = 1.2kW and so on? It should since the spindle drives the dials. Most meters I've seen have a F?S screw (just like the old wind up alarm clocks) for adjustment, etc.

 

[Modelworks]

You should be able to read it.
I think I saw a project on hackaday's website about someone that did it with an ir led and a receiver, bouncing the beam off the dial.

They are slowly phasing out those meters though.
The one I have now on my apartment has a lcd readout and no dial.
They can also read it from the plant, without ever sending anyone out and bill it based on time of day usage.


Edit:
Informative link
http://en.wikipedia.org/wiki/Electricity_meter

 

[Lord Banshee]

wow I like those new meters, i've had incorrect reading before. These new meters seem like it might be tad bit easier to get it right all the time

 

[Mark R]

The angular velocity of the disc is proportional to instantaneous power (with a bit of smoothing due to inertia, etc.)

The way these work is quite cunning. 2 coils (a voltage sensing and current sensing coil) produce an eddy current in the disc which exerts a force on the disc. The force is proportional to the instantaneous power. A seperate permanent magnet acts on the disc, acting as an electromagnetic brake. The EM brake exerts a braking force proportional to angular velocity - this makes the disc's velocity proportional to the drive force (and therefore power).

Just get an electronic current transformer operated meter with a pulse or serial port output, clip the transformer onto the incomer, and it's job jobbed.

 

[Rubycon]

Originally posted by: Mark R

Just get an electronic current transformer operated meter with a pulse or serial port output, clip the transformer onto the incomer, and it's job jobbed.

I was considering for noncontact instant readings bouncing a 650nm VLD from a DVD burner off the disc and converting the pulses to watts directly so it could be read like a non contact thermometer.

 

[Oceandevi]

I knew a guy who could adjust the old meters. For 60 bucks your bill went down to like 10 dollars. I never trusted him to come to my house though.

 

[Modelworks]

Originally posted by: Oceandevi
I knew a guy who could adjust the old meters. For 60 bucks your bill went down to like 10 dollars. I never trusted him to come to my house though.

Its good you didn't
It sets off a red flag when your normal bill is in the 100-200.00 range and suddenly its only 10.00 .
The penalties for meter tampering are over 5,000.00 per month added to your bill for as long as you need power from that company.

 

[Oceandevi]

Originally posted by: Modelworks

Originally posted by: Oceandevi
I knew a guy who could adjust the old meters. For 60 bucks your bill went down to like 10 dollars. I never trusted him to come to my house though.

Its good you didn't
It sets off a red flag when your normal bill is in the 100-200.00 range and suddenly its only 10.00 .
The penalties for meter tampering are over 5,000.00 per month added to your bill for as long as you need power from that company.

Yeah I never let him come over because he was freaking weird. Like the kind of guy who cut cat's off of cars and sold em for beer money.