Author Topic: Alstom Municipal kWh Meter  (Read 3168 times)

Sagittaire

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Alstom Municipal kWh Meter
« on: May 29, 2015, 09:27:05 AM »
In the South African context can anybody tell me how the municipal kWh meter measuring my home electrical consumption reacts when excess current is fed back into the grid? It's an Alstom C12 single phase meter. I can't find any documentation on it and don't know if it continues to count kWh although there is a negative amperage. I don't see any part number and nobody at the municipality can give me the specs.
« Last Edit: May 29, 2015, 09:34:13 AM by Sagittaire »

SeanB

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Re: Alstom Municipal kWh Meter
« Reply #1 on: May 29, 2015, 12:21:45 PM »
Difficult to say, as it varies from model to model, and even in certain serial number ranges and modification states. Most meters will work perfectly either forward or backwards, as they are registering true power, and power factor means that the meter might have to stand still with a large pure capacitance or inductive load.

Most meters however do have a lock on the measuring mechanism to prevent it from being made to run in reverse, which will drop the reading if the meter is allowed to run backwards. Thus it is very likely that the meter will not turn backwards with you feeding power back into the grid.

Your best case scenario is the meter is not prevented from running backwards, but it would have to be a unit that has not been replaced since at least the 1980's, as then the metros's started to do upgrades as there was a lot of people who were connecting a large welding plant to the mains, and this had such a low power factor that many meters would actually run backwards. Otherwise it will simply not register any power you feed back to the grid, and any excess power that you are not immediately using will simply flow back with the meter standing still and showing no consumption.

If you want to see the power delivered from the solar panel inverters simply go to your local Voltex and buy a meter and put it in line, with the line side fed from the panel and load side connected to the distribution board.

warlock

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Re: Alstom Municipal kWh Meter
« Reply #2 on: June 05, 2015, 09:08:18 AM »
mechanical meter "maybe", Digital NO! some digital like prepaid still continue to climb even if you are feeding back.