Dnk Posted July 10, 2018 Share Posted July 10, 2018 A friend has a Myford 254 lathe in his garage. I've had the motor checked at a local electric motor rewind company and that works as should but when fitted to the lathe nothing happens. I was told it could be down to a faulty capacitor/s but we can't find any on this lathe. This is a photo of the wiring box, any pointers what could be up or do i need to get a sparky out Quote Link to comment Share on other sites More sharing options...
jagman Posted July 10, 2018 Share Posted July 10, 2018 Looks like a 3 phase motor and it could be 2 phasing , you will have to check the contactor output is correct as one contact burnt out is possible - select in on and check supply at output contacts of contactor Can't see any capacitors in that box at all - any used are usually quite large Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 10, 2018 Author Share Posted July 10, 2018 Its a 3 phase motor that is adapted to run off single phase The motor is good and been bench tested by local place Quote Link to comment Share on other sites More sharing options...
jagman Posted July 10, 2018 Share Posted July 10, 2018 Start capacitors are used on single phase and usually in the motor connection block on the motor -3 phase motors are self starting (if all three phases are there ) Is it single or 3 phase motor? Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 10, 2018 Author Share Posted July 10, 2018 Its a 3 phase motor Quote Link to comment Share on other sites More sharing options...
jagman Posted July 10, 2018 Share Posted July 10, 2018 K1 is probably an on/off contactor and k2 and k3 are start and run contractors , k2/3 should have capacitors that they switch in (could be the two black boxes at the bottom - can't really see on my iPad ) - capacitor could be blown or a contactor not switching them in . Even if you get in a electrician - either the contactor or capacitor will need replacing (most likely defect) - depends on how much parts are and the electrician cost - if it pays to just fit new ones and see Quote Link to comment Share on other sites More sharing options...
jagman Posted July 10, 2018 Share Posted July 10, 2018 Sometimes a good old whack with a nylon hammer on contractors can free them up !!! Quote Link to comment Share on other sites More sharing options...
jagman Posted July 10, 2018 Share Posted July 10, 2018 https://www.practicalmachinist.com/vb/attachments/f11/29868d1294073808-modifying-three-phase-motors-single-phase-use-steinmetz-connection.jpg Probably wired like this - any flash,bang , smoke and flames and I'm out ...... I did say probably .... Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 10, 2018 Author Share Posted July 10, 2018 The two black boxes you refer to appear to be Suppresors,,,, RHZ 32 is written on them which i just googled Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 10, 2018 Author Share Posted July 10, 2018 Cheers for your help, i'll try giving the contactors a bash, gently and see what occurs Quote Link to comment Share on other sites More sharing options...
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