2–22
PQM POWER QUALITY METER – INSTRUCTION MANUAL
ELECTRICAL
CHAPTER 2: INSTALLATION
The RS232 port is only available with the display version. See Section 1.2.5: Order
Codes on page –12 for further details.
2.2.11 Dielectric
Strength
Testing
It may be required to test the complete switchgear for dielectric strength with the PQM
installed. This is also known as “flash” or “hipot” testing. The PQM is rated for 1500 V AC
isolation between relay contacts, CT inputs, VT inputs, control power inputs and Safety
Ground Terminal 6. Some precautions are necessary to prevent damage to the PQM during
these tests.
Filter networks and transient protection clamps are used between the control power, serial
port, switch inputs, analog outputs, analog input, and the filter ground terminal 5 to filter
out high voltage transients, radio frequency interference (RFI) and electromagnetic
interference (EMI). The filter capacitors and transient absorbers could be damaged by the
continuous high voltages relative to ground that are applied during dielectric strength
testing. Disconnect the Filter Ground Terminal 5 during testing of the control power inputs.
Relay contact and CT terminals do not require any special precautions
.
Do not perform
dielectric strength testing on the serial ports, switch inputs, analog input or analog
output terminals or the PQM internal circuitry will be damaged.
FIGURE 2–16: HI-POT Testing
NOTE
5
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