Fault detection method and system for elevator frequency converter [Invention]

By learning the three-phase voltage of the converter switching tube and corresponding three-phase current, and judging the rule of three-phase current, the U-phase, V-phase and W-phase of the converter can be judged correspondingly.

Be able to judge whether the current of elevator frequency converter is abnormal in time to avoid damaging the frequency converter.

Frequency output method of tweeter inverter, tweeter inverter and tweeter [Invention]

A frequency output method of the tweeter inverter, which changes the output frequency of the inverter by measuring the change in roll diameter to maintain a constant linear speed of the material.

No additional speed measuring rollers and speed measuring encoders are required, which reduces the cost of hardware and software development as well as the structural design difficulty of the decanter.

The invention also discloses a frequency converter of a wool steaming machine and a wool steaming machine.