Rockwell Automation 1403-DM_LM_MM Powermonitor II Instruction Sheet - Manual (Page 15)

Installation 2-3
1403-IN001A-US-P
Use instrument accuracy PTs when the voltage levels
being measured exceed the voltage input ratings. The
PT accuracy rating directly affects the system
accuracy. For maximum accuracy, the PT used must
provide linearity across the voltage range and must
introduce a minimal phase angle shift.
Note: Remember, for systes with greater than 120
volts applied to the voltage inputs, the PT
secondary must be configured to greater than
137 volts to switch to high voltage mode.
Example: A 600 V
L-L
(347 V
L-N
) direct-
connect system would be configured with a
PT ratio of 347:347.
Current Inputs and Current Transformer (CT) Selection
The Powermonitor II is available in two models: a 5
Amp or 1 Amp model. Each current input to the
Powermonitor II is internally CT isolated to 5kV.
Each current input may be connected directly into the
power line as long as the currents do not exceed the 5
Amp or 1 Amp ratings.
Customer provided CTs are required where input is
higher than the device rating. The values for the
primary and secondary CT ratings must be
configured into the Powermonitor II in order to
properly scale the displayed readings.
The accuracy of the current input reading is
dependent on the CT class. An Instrument Class 1 or
better is recommended. Care should be taken that the
combined load of wiring and the Powermonitor II
match closely to the VA rating of the CT for
maximum accuracy.
!
ATTENTION: A CT secondary
circuit must not be opened with
primary current applied. Wiring
between the CTs and the
Powermonitor II should include a
terminal block for shorting the CT
secondary circuit. Shorting the
secondary with primary current
present will allow other connections
to be removed if needed. An open CT
secondary with primary current
applied will produce a hazardous
voltage, which can lead to personal
injury, death, property damage or
economic loss.