Hello all...
Recently built a 4kW rotary 3 phase converter of the transformerless design for use on the domestic UK supply of 230v single phase. The unit works/starts and runs unloaded and will start another unloaded 2.2kW motor and remain reasonably in phase balance. The problems arise when the 2.2kW motor is loaded on start via connection to an air compressor. The motor starts but takes around 10s to build up to speed and when operating at full speed the phases become somewhat unbalanced.
Thought of detecting the low voltages in relation to the incoming supply of 230v and powering a donkey motor connected to the idler motor for a short duration to help bring the rotary converter idler motor back up to speed then disconnecting the donkey motor.
What are your thoughts?