PC5 SERIES WATT TRANSDUCER CALIBRATION MANUAL
Page 1
WATT TRANSDUCER
PC5 SERIES
1.
OPERATING PRINCIPLES
The power in an AC circuit is the product of
the voltage, current, and power factor
expressed as P = EI COS where is the
angle by which the current lags (inductive) or
leads (capacitive) the voltage. Power is a
measure of the rate at which work is being
done. Watt (or power) transducers provide a
means of measuring this and provide a signal
proportional to the rate at which work is being
done. The unit of electric power is the watt.
Some convenient power conversions: 1
horsepower=746 watts, 1 watt = 3.41
BTU/hour, 1 watt = 1 DC ampere X 1 DC volt.
The PC5 Watt Transducers utilize Hall Effect
multipliers to provide an output signal propor-
tional to the electric power consumed in a
load. The multipliers provide instantaneous
multiplication of the voltage and the current
on a continuous basis.
2.
TYPES
PC5 Watt Transducers come in four types.
A
Single Phase (One Element)
This type has one current sensor and
one voltage transformer. This mea-
sures total power in a two-wire circuit.
B
Polyphase (Two Element)
This type has two current sensors and
two voltage transformers. This trans-
ducer will measure total power in a 10/
3W or 30/ 3W Delta circuits without
voltage or load restrictions.
C
Polyphase (2½ Element)
This type has three current sensors
and two voltage transformers. This
transducer will measure total power in
a 30/ 4W circuit with balanced voltage
and unrestricted load.
D
Polyphase (Three Elements)
This type has three current sensors
and three voltage transformers. This
transducer will measure total power in
a 30/ 4W circuit without voltage or load
restrictions.
3.
RATING
3.1
STANDARD PC5 OUTPUT
The base unit PC5 Watt Transducer has an
analog signal output of 50 millivolts for single
phase, 100 millivolts for 30/ 3W, 10/ 3W or 30/
4W, 2 1/2 element, or 150 millivolts for 30/
4W. In each case output loading should be
greater than 100K
Ω
. Figure 1 shows the
output of the base PC5 Watt Transducer.
The sine wave shown is at twice the source
frequency. The "average dc" shown by the
dashed line in the figures below is
proportional to the true power and the sine
wave shown as solid lines is proportional to
