Old motor - single or three phase?


Joined Sep 24, 2015
I once used BNC connectors as audio connectors. Used coax as the cable. Low power stuff. Sometimes we use what we have. And I had a BUNCH of BNC's.


Joined Jan 23, 2018
I know a fool who refused to bid on a machine that he needed because the plug had 4 pins, and he assumed that it was a 3-phase machine, BUT the nameplate clearly stated 230 volts single phase. the hookup was two lines plus neutral plus green-wire ground. Those who don't read certainly lose out a lot. Good thing that the motor nameplate was so very explicit and easy to read..


Joined Jan 23, 2018
Wonder why a 230v 1ph motor had 2 live and a neutral?
It was an ice cream MACHINE, not just a motor. It had several motors and a lot of controls and a display AND there was a sealed unit compressor. So it had to have a neutral, since it did not include a transformer to supply all of those 120 volt items. It also had lights to make it look busy.


Joined Aug 21, 2017
However sometimes are in use the rather exotic motors of multiple pole shifting. By the outside it LOOKS like the ordinary 3-phase (just 6 wires innocently bunching out) but by fact, one measuring with a tester see all wires are internally connected. That is sure signal, one must look on the label (if still readable) and seeing the triangle-triangle-slash-ygrek ot ygrek-ygrek-slash-triangle its sure - You have in hands varipole motor used in most of old soviet stationary drill-machines, turner benches, mill-machines etc. Most widespread was 1500/3000 rpm, however existed even models with 4 different speeds. If interested how to connect within, here is the best material about that, sorry non-English, but diagrams are at all languages identical, and exists such tool as translate.google. http://elenergi.ru/regulirovanie-sk...-pereklyucheniya-chisla-par-polyusov.html/amp