howdy all.
have been lurking around here for a while now just reading and learning.
i recently brourght myself a Ostmac (king rich KRV2000) knee mill and a chinese lathe. both second hand and 3 phase. the plan was to use 2 vacon vp10 single phase to 3 phase invertors to run these machines on 1 phase power,
so far all going great, i have the lathe converted and running great but the mill is proving to be a little harder. i have sorted all the electrics out have have the motor running off the invertor but that is were the problem starts.
both the mill and lathe have 3hp motors on them. the mill motor is a modified king rich motor. it was a star winding only motor so had to have the delta winding dug out and brought to the terminal box.
the lathe motor is a brand new 3hp 3phase motor that i wired in delta. when running the lathe at full speed (1800rpm) the motor draws 5.5odd amps runs a treat. when i run the mill it draws 3odd amps and when i wind up the variable speed pullies the motor drops alot in rpm so much so it would stall if i keep winding the handle. i have watched the amp meter on the invertor and it stays at the 3 amps only even when loaded. (the motor is rated at 8 amps and the drive at 9.6 amps)
keep in mind the invertor is the exact same invertor i only have 1 invertor at this stage so it does work well with the lathe motor but doesn;t work on the mill motor.
i have even hooked the motor wires from the mill motor to the lathe so i am using the mill electrics but powering the lathe motor and all seems great.
i have spoken to a guy that has done this exact conversion and has had great sucess except he has used a different brand invertor but other than that the conversions are identical.
i spoke to the guy that did my mill motor mods and he said the motor is fine. i spoke to the invertor people and they say the motor is at fault.
i am now banging my head agaist a wall trying to nut this one out. for some reason the motor doesn't want to run on the invertor. if it was an easy job to install a new universal fit motor i would but it will mean making adapter plates and shafts and i want to avoid this if i can.
anyone got any ideas? before i throw a match to the lot.
cheers guys
dean