Sunday, April 12, 2015
One feature of this lathe may interest those who are technically inclined: while it has a 3-phase 60 cycle 240V motor, it will run just fine on a single phase of anything between 105 and 250 volts, one or three phases, and 50 to 60 cycles. How? There is an inverter included as an integral part of the lathe. Despite handling up to 2,500 watts, the inverter is quite small – the size of a small book. As recently as 10 years ago, this was much harder problem than it is today. Back in the '70s, the standard way to deal with power conversion issue like this was a motor-generator set (known colloquially as an “MG set”). These were made from an electric motor on the same shaft as a generator. The ship I was stationed on in the U.S. Navy used several of these – each the size and weight of a small car – to convert the ship's standard 3-phase 60 cycle 240V to single phase 400 cycle 110V power. Our computers used 400 cycle mains to reduce the physical size of transformers and the size of filter capacitors for the linear power supplies. Switching power supplies didn't exist.