Multiplication Factor for Energy Meters,

It is straight First one is 320 and the second is 30.

But sometimes the energymeters are calibrated in terms of if CT and PT ratios included.

There is no straight forward answer to this question. I would suggest you to go to the previous posting http://cr4.globalspec.com/thread/36700 and then you can find it by yourself. For your convenience, I am copying/pasting my comment from there:
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M.F (Multiplying Factor) value is written on the front dial of the energy meter. However, there may be different cases:

Case 1: The energy meter front dial doesn't have any M.F value or CT ratio and the meter is used without CT.

The M.F is 1 in this case, so the actual energy used for a period is equal to meter reading difference for the period.

Case 2: The energy meter front dial does have M.F value but no CT ratio: and the meter is used without CT.

The actual energy used for a period is equal to meter reading difference for the period multiplied by meter M.F.

Case 3: The energy meter front dial does have M.F value and CT ratio; and the meter is used with CT of same ratio.

The actual energy used for a period is equal to meter reading difference for the period multiplied by M.F.

Case 4: The energy meter front dial does have M.F value and CT ratio (example 100/5A); and the meter is used with CT of different ratio (example 200/5A).

In this case,

Actual M.F = Meter M.F x (200/100) = Meter M.F x 2.

The actual energy used for a period is equal to meter reading difference for the period multiplied by Actual M.F.

Case 5 (rare case but may happen): The energy meter front dial doesn't have any M.F value or CT ratio but the meter is used with a CT (say 20/5A).

In this case,

Actual M.F = CT ratio

So the actual energy used for a period is equal to meter reading difference for the period multiplied by CT Ratio.

There are more similar cases for PT ratio as well (but the logic is similar to CT ratio).

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Yours one could be either case 3 or 4 or 5.

- MS

Dear Guest,

The formula for meter display Multiplication Factor is:

Meter display Multiplication Factor = CT ratio * PT ratio * meter multiplier * other factors.

The previous responses were correct and detailed, but this formula can be applied universally in all situations.

Since Current transformer, potential transformer and meter multiplier (usually stated on the faceplate) information are self-explanatory, I will offer examples of 'other factors' for your benefit.

In the case of a window type CT, the primary cables are sometimes looped through the window more than one time, usually to get better resolution of a small current. This affects the output of the CT as any turns ratio would. So a primary cable that is looped and passes through a window CT twice would result in an 'other factor' of 0.5 (1/2) since the secondary CT current will be doubled.

In the case of bar-type or HV (HT) CT's, there are sometimes secondary tap or wiring configuration choices that have an additive or subtractive effect on the CT secondary current, and must be accounted for in the 'other factors' by the same logic.

Older meters sometimes had strange meter multipliers due to the dictates of gear ratios, and there is a formula for that, if needed. Usually the faceplate information contains that detail. Modern electronic meters have a multiplier of 1, but may need to be programmed to give a different effective meter multiplier in order to accommodate a legacy meter data system that was based on gear driven multipliers. Again, this can be accounted for in the 'other factors' value.

Regards, CJM