Thank you, waross.
I don't think it is a reliable phase loss detector, either. I believe it was designed to lower the cost.
And in this case, as the waveform is almost the same, it doesn't work.
With DC voltage high enough, VFD can work perfectly. In this case, the AC current of the remain two...
Thank you guys for your suggestions.
To waross:
Yes?we do use a VFD.
We disconnected the R phase wire from the power distribution box to our elevator and leave other things what it was. I suppose this simulates the missing phase failure.
We do not use a phase failure relay. Instead, we detect...
Thank you for your reply, itsmoked.
As I mentioned, when I did the measurement, the motor was not running.
Do you mean that the coil in the motor generates the missing leg? I don't understand. You know, as the elevator is not running, the IGBTs in the driving unit are shut off. I see no...
Recently, a field engineer complains that several elevators made by our company have missing phase detection failure. It is said that the elevator could run with R phase or T phase cut out. But this does not happen on the test machine in our factory.
So I went to the site and did some...
