Representative case · 01
Pitch motor draws high current
A “pitch motor current high” alarm on one axis; the pitch system is not ready at morning start-up.
Representative case. This page describes a fault pattern that is common in the field, as a diagnostic sequence. It does not describe a specific wind farm, turbine or date; numbers are examples only and limits vary by turbine type. On your own turbine the OEM instructions, LOTO procedure and safety rules apply; work near energised equipment is for authorised personnel only.
Symptom
A “pitch motor current high” alarm on one axis; the pitch system is not ready at morning start-up.
What was measured
Axes moved one by one in service mode: one axis is stiff. Winding balanced, motor brake releases fully.
Root cause
A slow oil leak at the output shaft seal; the gearbox ran short of oil for months and wore.
Fix and verification
Gearbox replaced to the OEM procedure; the other two gearboxes checked for level and leaks.
Lesson
Watch the slope, not the threshold: the current rise was visible in the SCADA trend months earlier.
Full version
The complete diagnostic sequence — possible causes table, step-by-step checks, maintenance checklist and common mistakes — is in the Turkish version of this case.