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Meter/Installation Data
Instrument Transformers
Potential Transformer
Current Transformer
Power Multiplier [(PT Multiplier) times (CT Multiplier)]
Enter the Numerator and Denominator for each instrument transformer. For example, a PT with a ratio
of 7200/120 has a numerator or 7200, a denominator or 120 and a multiplier of 60 ( 7200/120 = 60/1).
Meter Secondary Voltage (volts)
Meter Secondary Current (amps)
Base Conversion Factors
Quantity
Transformer
Voltage
Current
For Transformer Voltage, enter the Phase-to-Neutral value of Test Voltage previously calculated. For
Transformer Current, enter the Full-Load Current previously calculated. For Multipliers, enter the PT
and CT multipliers previously calculated.
TrfIT Secondary is the Base Value of Voltage and Current at the Instrument Transformer Secondary of
the Power Transformer. These numbers are obtained by dividing the Transformer Voltage and Current
by their respective Multipliers. The Meter/Trf values for Voltage and Current are obtained by dividing
the Meter Base values by the TrfIT Secondary values.
Load Loss at Transformer
No-Load Loss Watts (kW) = 1-Phase kW No-Load Loss = ______________
No-Load Loss VA (kVA)
No-Load Loss VAR (kVAR)
Electro Industries/GaugeTech
Numerator
120
5
Multiplier
Trf IT Sec
= (%Exciting Current) * (1-Phase kVA Self-Cooled Rating) / 100
= (______________) * (________________) / 100
= _______________ kVA
= SQRT((No-Load Loss kVA)
= SQRT((_________________)
= SQRT((__________________) - (_________________))
= SQRT (_________________)
= ____________________
Doc # E107706 V1.25
Denominator
Meter Base
120
5
2
- (No-Load Loss kW)
2
- (________________)
Multiplier
Meter/Trf
2
)
2
)
7-6
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