# Naked Science Forum

## General Science => General Science => Topic started by: NTYNUT on 29/08/2018 13:59:13

Title: How does an electricity meter work and how do you read it?
Post by: NTYNUT on 29/08/2018 13:59:13
Hello
I have Electricity meter how to take its reading and give to substation that how much i have consume energy generated by hydro electricity Dam
Title: Re: How does an electricity meter work and how do you read it?
Post by: NTYNUT on 29/08/2018 14:04:25
hello
Here is similar pic

Hydro_Quebec_meter_solid_state.jpg (271.63 kB . 1666x2475 - viewed 1586 times)
Title: Re: How does an electricity meter work and how do you read it?
Post by: Ophiolite on 29/08/2018 18:03:51
NTYNUT, if you look at the meter you can see that the units of measurement are kilowatt hours (kWH). (Please don't ask me what a kilowatt hour is. Do your own research this time and Google for it. There should be a good wikipedia article.) At Time A note the reading. At time B note the new reading. Subtract reading A from reading B and you have the electric consumption, in kWH, for the period of time between time A and time B.
Title: Re: How does an electricity meter work and how do you read it?
Post by: NTYNUT on 30/08/2018 06:43:26
Hello
i have done subtraction from final to last unit
1599kwh-1598kwh=1kwh
what will cost of it how to find time how much it work
Title: Re: How does an electricity meter work and how do you read it?
Post by: Ophiolite on 30/08/2018 16:25:13
Hello
i have done subtraction from final to last unit
1599kwh-1598kwh=1kwh
what will cost of it how to find time how much it work
Your electricity supplier will be able to tell you the cost per kWH, or you can check your most recent bill.

The meter does not record the time that you have been using electricity.
Title: Re: How does an electricity meter work and how do you read it?
Post by: NTYNUT on 31/08/2018 06:59:19
Hello
Does electricity meter also tell power factor
Title: Re: How does an electricity meter work and how do you read it?
Post by: evan_au on 31/08/2018 08:48:52
Residential rotating disk meters did not record power factor or time of use.

But these features come “for free” in the software of an electronic electricity meter.

These measures are useful when investigating potential theft of electricity - and this is a major problem in an industry that operates on very slim profit margins.
Title: Re: How does an electricity meter work and how do you read it?
Post by: NTYNUT on 31/08/2018 08:51:32
Hello
I have seen in electricity bill that show power factor mention in it
how they measure power factor of electricity meter
Title: Re: How does an electricity meter work and how do you read it?
Post by: Bored chemist on 31/08/2018 13:07:03
Why don't you google this and find out?
Title: Re: How does an electricity meter work and how do you read it?
Post by: evan_au on 31/08/2018 13:10:28
Quote from: NTYNUT
I have seen in electricity bill that show power factor mention in it
Power factor is very important in an industrial power supply, and would often be shown on a commercial power bill.

Poor power factor wastes power, and costs the supply company real money.

There are a number of ways to measure it:
- In the short term, it is the phase angle between the 50Hz voltage and the 50Hz current, which could be measured on a cycle-by-cycle basis. Take the cosine-1 of this angle.
- It could be measured with a Fast Fourier Transform, over several cycles. Measure the real & imaginary components of the power.
- But a bill is typically issued monthly. One easy way to calculate it over a long period of time like a month  is to accumulate the real power and reactive power (VARS) in separate registers. The real power is charged as power consumed. Use the VARs to calculate the average phase angle over the month. The Power Factor is the cosine-1 of this phase angle.