Repair of the frequency inverter for elevators

This repair was specific for the unique conditions in which the device itself was. A lightning striking the installations connected to the elevator had caused the malfunction of the device.

The lightning striking the installations of the elevator power supply caused the protective parts in the device to burn out, but also destroyed the IGBT module. The interesting aspect of this repair was that, despite high resistance to voltage, the optocouplers that galvanically separate the power circuits from the electronic, control circuits, were damaged. This had caused a series of short circuits on the protective diodes, diodes – surge arresters and on the protective MOSFET transistors.

The testing of this device is protected by a business data confidentiality agreement, hence the photos show only the state of the IGBT module which was destroyed by the lightning, and the device after the repair.