15KW inverter repair
There was an old HITACHI SEIKI CNC lathe for repair. The main problem was alarm after spindle rotation request. YASKAWA inverter for spindle was the main issue, actually.
After close look at it, the issue was -1oc alarm on the transistor inverter.
YASKAWA inverter manual
Firstly, the manufacturer manual has to be found. Even the name over the web was different than the nameplate. The inverter series named Varispeed-626MTIII Drives on the web.
The complete manual can be downloaded below.
Troubleshooting
As shown below, in troubleshooting section, the reasons for the issue after starting operation was:
- main circuit connection error
- load shorting
- ground fault
- defective transistor module
The only thing can cause this issue was faulty transistor module.
Transistor module disconnection for checking
The transistor module tested with ohm meter after disconnecting all the wire on PCB and the module, as can be checked below.
Checking method
As shown below, in the inverter manual, the ohm meter has been used to check the transistor module.
One of the transistor was defective.
Replacement
This inverter needed 2DI200A-050 transistor from Fuji electric, Japan.
We first tried Yaskawa agent in Australia. The parts found in US stock. costing around AU$3K.
Then we looked for it online on google, somewhere like ebay, Ali Express and so on. Ended up ordering from Alibaba website for AU$100 each, all together around AU$400 included DHL express, delivered in Botany, Sydney.