Medium voltage switchgear QMT
85
Installa
tion manual
Anomalies
Possible causes
Checke and remedies
Circuit-breaker does
not close
Supply voltage of the auxiliary
circuits too low
Measure the voltage: it must not be
lower than 85% of the rated voltage
Operating or accept contacts
locked closed
Check the state of contacts in series
with the release
Supply voltage different from the one
indicated on nameplate for these releases
Check the voltage indicated
on the nameplate of the releases
Faulty switching circuit
Check connections, fuses, protection
switches and accept contacts
Incorrect electrical connections in the
power supply circuit
Check the connections with the
relevant diagram
Release coils interrupted
Replace the coils
Operating mechanism locked
Operate manually;
contact SEL if the fault persists
Key not inserted in the relative
operating mechanism of key lock
Insert and turn the key
Under voltage release not energized
Check the supply circuit
Shunt opening release
remains energized
Check the supply voltage and the
contact in series with the release coil
Spring charged locked
Supply voltage of the auxiliary circuits
too low
Measure the voltage: it must not be
lower than 85% of the rated voltage
Operating or accept contacts locked
closed
Check the state of contacts in series
with the release
Supply voltage different from the one
indicated on nameplate for these releases
Check the voltage indicated on the
nameplate of the releases
Faulty switching circuit
Check connections, fuses, protection
switches and accept contacts
Loose wire clamping screws
Check tightness of the screws
Incorrect electrical connections in the
power supply circuit
Check the connections with the
relevant diagram
Operating mechanism locked
Operate manually;
contact SEL if the fault persists
Surface discharges
Conductive dust on insulating parts
Clean and check the insulation
resistance (Megger 2500V)
Summary of Contents for QMT Series
Page 1: ...Y4419D 01GF 18W12 QMT Manuale installatore Installation manual ...
Page 2: ...2 IT UK ITALIANO 3 ENGLISH 45 QMT ...
Page 15: ...Quadri Media Tensione QMT Manuale installatore 15 Tipo 2 Tipo 3 Tipo 4 ...
Page 44: ......
Page 57: ...Medium voltage switchgear QMT 57 Installation manual Type 2 Type 3 Type 4 ...
Page 86: ...86 Notes ...
Page 87: ...87 ...