11-05-2014, 09:16 AM
I suggest you follow Ed instructions. I have fitted capacitors to my friends sud pumps motors in the past using capacitors from fluorescent light fitting. As Ed has said, keep increasing the cap value until the three voltages are about the same. I fitted them in an earthed metal box at the back of the lathe, done a few, it works and never had any problem starting on load. I have made up similar boxes with two lots of capacitors, one lot start ( large value) , the other run ( much smaller value). I wired them such that both lots were in circuit on start up and then the large value was disconnected. I used two small contactors to do the switching and all was controlled by two push buttons. When the green push was depressed both contactors pulled in, when you released the pressure on the green button one contactor dropped out leaving the small value cap in circuit. If there was a mains failure the whole thing provided no volt release. This worked for years on a Colchester Bantam lathe. On the first one I made I found that it took a bit of trial and error to get the voltage near the same, so after that I fitted a big rotary selection switch for the start capacitor arrangement. The idea is certainly not new. Oh one thing, fit discharge resistors to each cap and ensure that they have a high working voltage.Ted
