𝗙𝗿𝗼𝗺 𝗜𝗻𝘀𝗽𝗲𝗰𝘁𝗶𝗼𝗻 𝗮𝘁 𝗛𝗲𝗶𝗴𝗵𝘁 𝘁𝗼 𝗙𝘂𝗹𝗹 𝗥𝗲𝗰𝗼𝘃𝗲𝗿𝘆 🏗️

Wolfer electric motor, installed high up in a crane!

An older Wolfer electric motor, installed high up in a crane, was recently inspected and overhauled.

Our field service team first carried out on-site inspection and electrical measurements at height. Based on the condition found, the motor was removed and transported to our facility in Dordrecht for further investigation and repair.

Initial findings

The motor showed reduced rotor insulation, mainly caused by moisture ingress and carbon contamination from the slip ring system.

Work carried out

– Mechanical and electrical diagnostics on arrival
– No-load test (incoming condition)
– Partial blasting and application of epoxy primer
– Bearing and seal overhaul
– Shaft alignment and correction
– Steam cleaning of stator and rotor
– Oven drying of stator, rotor and brake assembly
– Terminal box refurbishment and resin casting
– Reassembly, sealing of endshields and repainting (RAL 7040)
– Final no-load test after overhaul

Components replaced

– DE bearing: NU314-C3 (ECP)
– NDE bearing: 6314-2RS1-C3 (ECP)
– Shaft seals (DE & NDE)

Results

Rotor insulation restored from 5.3 MΩ to 400 MΩ (+7447%) ⚡️
The motor has been tested and released for operation, with all key mechanical and electrical parameters within specification.

Working on this type of equipment often starts under less-than-ideal conditions on site. Proper recovery, however, requires controlled workshop processes.