A client of mine has a 590+ Series 2 Frame 2 DC Integrator that has performed successfully in a PPR pipe extruder machine for a number of years without any issues.
A few weeks ago, I was informed that the motor controlled by the drive stopped working and the drive displayed "Field Failed. On checking, I found the listed components burnt on the main board.
These components are marked In red in the first attached picture. All burnt components are shown in the second attached picture.
1. Controlled Bridge Rectifier - VGO36-16io7 - shorted gates to cathodes of thyristor.
2. The 2 0.033uF PME 261 capacitors on lower part of the board
3. The 4 47nF PME 271 capacitors on the lower part of the board.
4. The 3 27 Ohms resistors on the lower part of the board.
All burnt components were replaced and the drive reinstalled. However, on powering up the machine, the drive displayed "Field Failed" alarm. On checking field rectifier module, I found its thyristor gates are shorted to the cathodes.
Please note that the drive's parameters were not altered.
Could anyone please suggest the possible cause of the failure of the components and what the solution is.