Specs and source for Powerstat paralleling choke?

Thread Starter

Just Another Sparky

Joined Dec 8, 2019
I recently found a steal of a deal on a 3-phase Powerstat 146U-3. According to this datasheet it is permissible for me to reconnect all three cores in parallel for operation at 0-140VAC, 90A.

Now my intention is not to try to pull 90 amps at 120 volts; rather, with the addition of a suitable rectifier it would serve as a very easy, versatile and durable way for me to derive high current variable DC for e.g. bulk charging batteries, testing large DC motors, experimenting, etc. Also, the extra overhead will be handy for coping with the locked rotor currents of induction motors without damage to the variacs' delicate commutators or brushes.

The problem I'm running into is that a 3-channel common mode choke is called for to equalize the output currents from all three cores. The datasheet calls for a Powerstat T6065, but I can't seem to find any information or sources for that.

Has anyone encountered these paralleling chokes before? If so, what do you suppose might be a suitable inductance to insert in lieu of the OEM part? Would it be safe to fuse each wiper individually with a common-mode choke in place, or do I need to use a 3 pole common-trip circuit breaker instead to prevent overvoltage across the choke windings in the event only one or two of the fuses open? (Thinking along the lines of what happens with an unburdened CT.)

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