Myford wiring

I have a single phase Super 7 and a later (square tray) type industrial stand with 3 phase switchgear on the square control panel.

Please can anyone advise me if it is possible to rewire the latter to run the single phase motor or if the single phase switchgear is substantially different and therefore requiring completely new components?

Thanks.

Hello Jeremy,

The usual dodge is to wire the motor through the 3 phase starter by looping the live through two of the ways in the starter so that the contactor sees a balanced current loading in all its ways. Tubal Cain's Handbook shows this diagrammaticaly and there are other publications showing such wiring diagrams.

For it to work satisfactorily of course the load drawn by the motor should match the capacity of the 3 phase contactor, I imagine they won't be far apart in this case.

If though you are the least bit nervous about this get a professional to check and wire it for you.

Brian

Jeremy,

You will also need to check whether or not the contactor is fitted with a coil suitable for the higher 3 phase voltage or for the lower single phase voltage. If the former, then it will not pull in when used with 230VAC. Replacements are normally readily available from most industrial electrical wholesalers or distributors.

In addition, as Brian advises, you should always get your work checked,tested and formally certified by a suitably qualified and competant electrician before connecting any equipment to the supply.

Brian and Trevor,

Many thanks for this advice. Since posting this request I have aquired an original wiring diagram for the single phase Myford ind. stand so am in a position (with guidance from more knowledgeable clubmates) to wire it up correctly. I am wondering now though if both the 3 and single phase controls used the same Sprecher + Schuh contactor ( in the latter case the CA 3-16) but with the appropriately rated coil....I had tried the 415v coil and as I suspected it just rattled away without locking! The CA 3-16 terminals all make sense with the diagram but it would be nice to know if it were the same contactor and overload before we reassemble it.

Can anyone advise me further please?

Thanks, Jeremy.