Megger PMM-1, Руководство пользователя

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5. SERVICE AND MAINTENANCE
The components and techniques used by Megger are mostly standard and
readily understood by competent, trained technicians. Some calibration and set-
up procedures, however, are very difficult to perform in the field without the test
jigs and accurate standards available to factory personnel. Customer repair and
calibration are not recommended.Please contact your
Megger representative
should service or calibration be required.
6. ADDENDUM – Using PMM-1 for Delta Power Measurements
The North American Addendum Using the PMM-1 Power Multi-Meter
For Delta Power Measurements
Electrical energy is the same regardless of the system configuration in which it is measured. In other
words, 500 watts is 500 watts regardless of whether it is distributed throughout a 3 phase wye (Y) system
or a delta (
∆ ) configured system. Blondel’s Theorem suggests that the number of watt meters required to
accurately measure energy within a circuit is one less than the number of conductors in that circuit. In
keeping with Blondel’s energy measurement philosophy, it becomes necessary to employ a minimum of
two watt meters to measure energy in a delta system, whether it be an open or closed system. Due to
the fact that the PMM-1 does not have a specific preset measurement mode for performing power
measurements using a two watt meter method, the following procedure is set forth for that purpose.
Before going too far into an explanation of how these measurements are made, let’s take a look at a
diagram representing PMM-1 internal connections.
Connections
External
Connections
Y Configuration ∆ Configuration
V
1
= V
AN
= V
A
– V
N
V
1
= V
AB
= V
A
- V
B
V
2
= V
BN
= V
B
– V
N
V
2
= V
BC
= V
B
- V
C
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