![]() These units are really meant to drive _motors_, not general purpose 3 phase loads. The downside is that the output AC is rich in electrical noise and harmonics. These devices are relatively inexpensive, and have no moving parts. The output AC can have arbitrary frequency and voltage, which gives you the ability to control the speed of a three phase motor. They work by taking their supply power, converting it to DC, and then using electronics to convert the DC to 3 phase AC. These are actually used to control motor speed, but can also be used to convert single phase to 3 phase power. The final approach is something called a VSD or inverter. Also you have a spinning machine which means mechanical noise, and the need for bearing maintenance. The downside of this is that the output may not be well balanced, which can cause heating issues in motors. The benefit of the rotary phase converter is that you get clean sinusoidal output, and only part of the power is actually passing through the converter for a load that only has a portion of 3 phase loading, the bulk of the power can come directly from the single phase supply. A special starter triggers this motor to turn, and the third terminal of the motor _generates_ the 3rd terminal of the three phase supply. ![]() ![]() This is simply a 3 phase motor with two of its terminals connected to your single phase line. This is not really a likely option, but I mention it for background.Ī very common mechanical approach is something called a 'rotary phase converter'. You have a single phase motor that runs off your single phase supply, and drives a generator which produces 3 phase power. The cleanest (and most expensive) way to produce 3 phase is a 'motor generator set. It may be that Selmi has already designed for an internal single to 3 phase converter to run the motors.įailing this, there are several approaches to producing 3 phase from single phase however these all have their issues. Any heating element can be reconnected for single phase operation, and the control circuits use 24V derived from a single phase converter/transformer (it is not clear to me from the manual if the control is 24V DC or AC). I found a Selmi Plus user manual online, and it shows a couple of three phase motors.but most of the machine is using single phase power. Before you go down the path of 'synthesizing' 3 phase power from a single phase source, the first thing you should do is contact Selmi and find out how much it would cost to convert the machine for single phase operation.
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