Hi Mark:

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Thanks for your post. You much more accurately described what I thought was going on (the use of the word “dumb” was, well, dumb)!

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Some of my machines (like the aforementioned x-motions) need that 1Ph electricity to power up electronics. In my case the 3PH is 400V (for the drive motors), and the 1PH or extra pin is 240V (presumably for the heads up display, etc.). I always thought there were 3 hot pins and 1 earth, and the “fifth” pin was the neutral that may or may not be needed for a light, or electronics, or an additional motor, or whatever.

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Consequently, like what others have said, I have standardised 5 pin sockets for all my 3PH machines, and the fifth or neutral pin is wired or not, as required.

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Have I understood this correctly, at the most basic level of course?

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