Schneider Electric 4000 manual Calculating the KILOWATTHOUR-PER-PULSE Value

Chapter 5—Input/Output Capabilities	63230-300-212
Calculating the Watthour-Per-Pulse Value	April 2001

CALCULATING THE KILOWATTHOUR-PER-PULSE VALUE

This section shows an example of how to calculate kilowatthours per pulse. To calculate this value, first determine the highest kW value you can expect and the required pulse rate. In this example, the following assumptions are made:

•The metered load should not exceed 1600 kW.

•About two KYZ pulses per second should occur at full scale.

Step 1: Convert 1600 kW load into kWh/second.

(1600 kW) (1 Hr) = 1600 kWh

	(1600 kWh)	=	“X” kWh
	1 hour		1 second
	(1600 kWh)	=	“X” kWh
3600 seconds			1 second
	X = 1600/3600	=	0.4444 kWh/second

Step 2: Calculate the kWh required per pulse.

0.4444 kWh/second

= 0.2222 kWh/pulse

2 pulses/second

Step 3: Round to nearest hundreth, since the circuit monitor only accepts 0.01 kWh increments.

Ke = 0.22 kWh/pulse

Summary:

•3-wire application—0.22kWh/pulse provides approximately 2 pulses per second at full scale.

•2-wire application—0.11kWh/pulse provides approximately 2 pulses per second at full scale. (To convert to the kWh/pulse required for a 2-wire application, divide Ke by 2. This is necessary because the circuit monitor Form C relay generates two pulses—KY and KZ—for every pulse that is counted.)

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