Building A Variable Frequency Drive For A Three-phase Motor

January 19, 2012 by Mike Szczys 23 Comments

Here are the power and driver boards that [Miceuz] designed to control a three-phase induction motor. This is his first time building such a setup and he learned a lot along the way. He admits it’s not an industrial quality driver, but it will work for motors that need 200 watts or less of power.

The motor control board uses an MC3PHAC driver IC and an IRAMS06UP60A handles the power side of things. The majority of the board design came from studying the recommended application schematics for these two parts. But that’s far from all that goes into the setup. Motor drivers always include levels of protection (the whole reason to have a driver in the first place) and that comes in several different forms. [Miceuz] made sure to add EMI, over voltage, and over current protection. He discusses all of these, sharing links that explain the concepts of each.

3-phase Jacob’s Ladder

April 15, 2011 by Mike Szczys 18 Comments

Two sparks are better than one, a sentiment that was never more blindingly illustrated than with this three-conductor Jacob’s Ladder. The build centers around three-phase power, which uses a trio of alternating current sources sharing the same frequency, but offset by 1/3 from one another. If we’re reading the schematic correctly, [Jimmy Proton] is using normal mains as a power source, then connecting three transformers and a capacitor to set up the different phases. Two of the transformers, which were pulled from microwave ovens, are wired in antiparallel, with their cores connected to each other. The third transform is connected in series on one leg of the circuit.

The video after the break starts with the satisfying hum of power, only to be outdone by the wild sparks that traverse the air gap between conductors of the ladder. After seeing the first demonstration we kind of expected something to start on fire but it looks like all is well. We’ll probably stick to a less complicated version of Jacob’s Ladder.

Continue reading “3-phase Jacob’s Ladder” →