I much prefer 3 phase for the lathe, you get better surface finish, less issues with the start/stop cycles killing the start capacitor, variable speed to dial in the sweet spot, electronic braking, etc. I have done about 6 complete VFD controls system replacements for the PM-1440GT and dozens on 1340GT's and quite a few for larger machines. I also put together a basic VFD install manual for using the contactors to switch the VFD inputs for the 1340GT and 1440GT lathes, but assumes you have basic electric skills. If it is something you want further info, send me a PM with your email and I will send you the info.
A VFD is a bit more complex to install, and definitely not a connect the wires to the lathe input and have it work. An RPC works better in that situation, you would need a minimum of a 5-7.5 Hp RPC for a 3 Hp lathe. Down side is they are running all the time vs. the lathe which is intermittent. VFD installs on smaller lathes 3 Hp and smaller are more cost effective, past that the cost go up, but also the cost of an RPC.
Hello!
I have lately purchased an old COLCHESTER MASCOT 1600, 80 inch Gap Bed Lathe in an auction in good working condition. It's a 1976 make machine, which I am cleaning completely at the moment (without dismantling the gear box/drives).
Though I am not an electrical engineer ( I am a mechanical engineer with good understanding of elementary electrical engg- graduated 30 years ago!)
I want to make the following modifications to the lathe:
1 Install an oil filter between the hydraulic oil tank and input to the gear box
2 Install a VFD screw pump for coolant to control pressure of the coolant through the internal cooling tool holder I envisage to use- Sandvik parting tool holder, with a banjo connection from the back of the holder to the coolant pump. Coolant pressure can be regulated from 5 bar to 70 bar. Need to install suitable coolant pipe.
3 Install a coolant skimmer to trap floating dust, turned sludge, run separately. At present the coolant pump of 0.5 HP is provided, 1 phase.
4 TO INSTALL A VFD on this lathe. The lathe comes with a 12.5 HP 3 phase induction motor. Here I need support
Could you suggest what needs to be done.
There are plethora of videos on You tube that show converting three phase to single phase, in home shops and hobbyist. But I am running an engineering company, a foundry with machine shop.
Could you suggest way forward? Now Colchester models have variable speed drives. They result in cost savings based on the load put on the machine. Colchester Mascot has 16 speeds from as low as spindle RPM to 1600 RPM using full rated power of the motor. I think the whole electric needs to be changed...including a VFD compatible motor, and a VFD module to suit 12.5 HP/ 16 speed fully geared lathe.