Si71-502 Troubleshooting
Troubleshooting 53
1.18 Power Transformer
Error Detection
Method
Check resistance and voltage with tester, and insulation resistance with megger.
Error Generating
Conditions
Possible Causes
Troubleshooting
Resistance of primary side of transformer: approx. 140Ω
Resistance of secondary side of transformer: approx. 1.9Ω
Voltage at secondary side of transformer when rated voltage is applied to primary side: approx. 26 VAC
Insulation resistance between primary side of transformer and case: 100 MΩ or higher
Insulation resistance between secondary side of transformer and case: 100 MΩ or higher
Insulation resistance between primary side and secondary side of transformer: 100 MΩ or higher
Check resistance of
primary side of
transformer.
Does
measured
resistance
deviate significantly
from values
shown
below?
YES
NO
Check resistance of
secondary side of
transformer.
Does
measured
resistance
deviate significantly
from values
shown
below?
YES
NO
Apply rated voltage to
primary side of
transformer, and check
output voltage of
secondary side
of transformer.
Does
measured
voltage deviate
significantly from
values shown
below?
YES
NO
Transformer is faulty.
Transformer is faulty.
Transformer is faulty.
Transformer is normal
(HF016)
(HL037)
Check resistance and voltage