ECN Forum Forums General Topics of the Trade General Discussion Area High Power Bills

A lot of people look at a meter and see the disc spin around fast or slow. The thing forgotten often is to look at the constant of the meter. In USA Kh and in NZ revs/kWh.

For example: A 750 rev/kWh meter runs twice as fast as a 375 rev/kWh meter and four times as fast as a 187.5 meter under the same load.

An on site meter test is likely to be charged for also when it's done by an external test house. We were in that position a few years ago after the POCO contracted everything out. Sometimes for political reasons the POCO waived the charge for the customer.

If a meter gets changed for whatever reason, some customers change useage sometimes too in hope for a refund if a POCO meter was for example within its accuracy but on the + 2% side.

Quote:
"A lot of people look at a meter and see the disc spin around fast or slow. The thing forgotten often is to look at the constant of the meter. In USA Kh and in NZ revs/kWh."

Good point. I remember testing a meter for an old lady that ran perfectly, but she was adamant about changing it anyway. So I took out her perfectly good 3.6 Kh meter and stuck in a perfectly good 7.2 Kh meter. She was thrilled that it ran half as fast, stuck her finger in my face and said, "Told you so"!

Quote:
"Don't have a clue how they would go faster, never gave it much thought."

I can't speak to the electronic meters, the the mechanical ones with the rotating disk have magnets inside.
The disk is basically an induction disk motor and spin in response to the current flowing through the meter. Small magnets are adjusted to slow down the motor as needed in order to calibrate it.

Roger:
I had the same thing happen with my neighbour ( bit looney but ya know).. PoCO changed his meter and his bill was unreasonably high the next reading... He took readings and did all that and came to the conclusion the new meter was not calibrated correct.. after about 6 mos of complaining the PoCo changed the meter again and everything returned to normal but did he get reimbursed?? Heck no!!

Now.... If we can only convince him that only opening his main water valve 1/4 of the way will NOT reduce his water bill......... Ah well thats another story!

I was never one of the scholars when it comes to the math, but I have heard before of the next door neigbor loosing his neutral, and now his gec/h20 connection and your gec/h2O connection causes added impedence to your neutral return path up the service drop. Your electric bill now goes up. Was this urban myth sparky baloney?

Sounds like a lot of c..p to me. The meter measures voltage and current, if there is a lower voltage there is less flux from the voltage coil, also the full amount of power can't be drawn by appliances.

For resistive loads like heaters and lamps.
e.g. a 1100 watt heater will draw 10 amps at 110 volts. heater R. = 11 ohms.
Now say low voltage at 80 volts the heater R. = still 11 ohms. U=I*R then 80/11 =7.27Amps drawn. Power drawn from mains P=I²R then 582 Watts can be dissipated as heat hence the meter will run a lot slower too. ( this is nearly ½ power for ± 30% mains voltage drop.)
for inductive loads
Low voltage is not ideal for motors in fridges, with lower voltage they have not full torque available to start into a load, e.g. drive the compressor and may stall and draw a high current till the thermal overload kicks in or the motor burns out.
A transformer will provide lower output voltages hence less VA's into it's secondary load.
Switchmode power supplies don't really care to much about lower supply voltages. the duty cycle of the on / off switching time of the powertransistor will change.

See this thread for some comments about residential meters and missing neutrals.
https://www.electrical-contractor.net/ubb/Forum1/HTML/006185.html

-Jon

Thanks winnie.

I did participate in that thread and am aware what was discussed.