Electro-Voice 250 Meter/Installation Data, Base Conversion Factors, Load Loss at Transformer

Meter/Installation Data

Instrument Transformers	Numerator	Denominator	Multiplier
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)	120
Meter Secondary Current (amps)	5

Base Conversion Factors

Quantity	Transformer	Multiplier	Trf IT Sec	Meter Base	Meter/Trf
Voltage				120
Current				5

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)	= (%Exciting Current) * (1-Phase kVA Self-Cooled Rating) / 100
	= (______________) * (________________) / 100
	= _______________ kVA
No-Load Loss VAR (kVAR)	= SQRT((No-Load Loss kVA)2 - (No-Load Loss kW)2)
	= SQRT((_________________)2 - (________________)2)
	= SQRT((__________________) - (_________________))
	= SQRT (_________________)
	= ____________________

Electro Industries/GaugeTech Doc # E107706 V1.25 7-6