Megger TTR320 Series, Instruction Manual

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M
AVTMTTR320-EN Rev A Oct 2008
34
Troubleshooting
The Troubleshooting Guide, Table 6-1, is arranged to help you evaluate the
reasons for TTR test set malfunction. The table lists possible test set
malfunctions which may be encountered during operation and lists possible
causes. Electronic circuit repairs should not be attempted in the field. Refer to
Repair section. Refer to Section 7 for a list of spare parts.
Table 6-1. Troubleshooting Guide
MALFUNCTION POSSIBLE CAUSE
Display stays blank after POWER switch is
turned on.
ƒ
No service power.
ƒ
Defective line cord.
ƒ
Defective fuse(s).
ƒ
Defective display or electronics.
Error message:
ƒ
ANALOG OFFSET VOLTAGE
HIGH
and/or
ƒ ANALOG GAIN OUT OF
TOLERANCE appears after self-test is
complete.
Out of tolerance condition(s) in
measurement circuit.
Red TEST VOLTAGE ON lamp does not
light on start of testing.
ƒ
Defective lamp.
ƒ EMERGENCY TEST OFF switch
is not released.
ƒ
Problem in measuring circuit.
One of the following messages appear on the
test result screen.
ƒ
CHECK CONNECTIONS
ƒ
PHASE A (or B, or C) EXCITATION
CURRENT TOO HIGH;
ƒ TURNS RATIO TOO LOW, <0.8; or
PHASE A (or B, or C) TURNS RATIO
TOO HIGH;
ƒ
CHECK PHASE A (or B, or C)
CONNECTIONS, REVERSED;
ƒ
CHECK PHASE A (or B, or C)
POLARITY
ƒ
Abnormal operating condition.
ƒ
Incorrect setting of
TRANSFORMER TYPE in the
quick test setup or the full test setup
1 menus.
ƒ
Incorrect connection of leads.
ƒ
Defective test leads.
ƒ
Incorrect marking of a transformer.
ƒ Problem in test specimen.
ƒ Problem in measuring circuit.
RATIO and/or Iexc (mA) readings erratic.
ƒ Defective test leads (open circuit,
poor connection).
ƒ Severe abnormal transient in service
power.
ƒ
Problem in test specimen (poor
connection).
ƒ
Problem in measuring circuit.