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Anyone based near Guildford, Surrey UK who is an electrician and knows about lathes who can assist with an inverter installation?


Hot Rolled
Mar 24, 2020
Hi I own a Schaublin 135 lathe which has been the subject of a re-build thread on this site in the Schaublin forum and also a thread trouble shooting some electrical issues.

Currently the 135 is working but not in high speed mode, this is due to the fact a RPC bought to run this machine is just not holding voltage when the motor draws start up current in high speed and the contactors drop out tripping the action.

Following a lot of work to consider a soft start and rectification of some broken electrical items, covered on another thread on this forum it has been suggested I seriously consider a 220VAC single phase to 380VAC 3 phase inverter, seems this might be a solution but require someone with lathe or machinery electrical experience to help wire and program the inverter. I have electrical schematics and a fair understanding of the machines wiring methodology.

Anyone able to help, locally based would be better as its always easier to do these things in person, happy to pay time, make tea or coffee and the workshop is warm and dry :)
You would get more offers with Guinness as payment.

Your RPC might be dropping out due to a boundary condition with current limiting protection.
Explain about the RPC or pics. It's good to have a working RPC for a backup plan if inverter trouble happens.
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If the price doesn't put you off, you could go with a 3hp or 5hp pre-configured and sized 230V to 400V drive from Drives Direct. "Digital Phase Converter" in their lingo. It'll supply the Schaublin directly without any modifications needed. Within it's ratings it'll supply any other three phase kit you've got. I use a 7hp one of them to supply a Hardinge HLV lathe, Jones & Shipman 1400 Surface grinder, Beaver milling machine, Meteor drill grinder, BCA jig borer and Wolf pedestal grinder (don't tend to have more than two larger machines running at a time :D

Prior to that I had a large (23kVA) Danfoss VFD that I got from a friend for a tenner, but that died and wasn't worth getting the failed current sensor repaired.

PS:- Congratulations on the Schaublin. Nice lathe!