Jones and Shipman 540

I might be buying a J&S 540 surface grinder in the not too distant future. as per usual with most old ex-professional machinery, its three phase. Does anyone here run a 540 ? And if so how do you power it ?

The usual VFD, or VFD's ?

I run a 1400, the big brother of the 540, plus a Hardinge HLV lathe, Plus a Beaver VBRP mill. They all run off a single, shared, Danfoss VFD. Without access to one of those, I'd probably go for a rotary converter.

Unless it's quite recent, it's likely that the motors are 415V star only and can't be reconnected to use 240 delta. With an over-rated VFD, a 240-415 transformer and a bit of configuration you can almost certainly run it with a single VFD, after all, that's what I'm doing, but it depends on the VFD.

I have a 540 which I run from a static phase converter. As the machine has a motor for the wheel and a motor for the hydraulics my understanding (which may well be wrong as evidenced by Marks post!) is that I couldn't use just one inverter, and that the switchgear could not be between the inverter(s) and the load. Hence the phase converter. I spoke to a very helpful gentleman at Transwave who suggested that I switch on the wheel before the hyd, and switch off in the reverse order.

Thanks for the replies. I am not sure how old the machine is, apparently it was in a workshop and not used for a long time. Sitting in a corner covered in dust. I hope its a later model so i can use a VFD as they are so convienient to set up and use.

You can use just one inverter and plug it straight in as 440v 3ph would ie through control panel, isolators, relays etc. Not limited to the pseudo effect of a Rotary convertor.

If you fit a VFD you could change the pump motor for a single phase one. I did that. I also managed to find the star point and re-wire the windings for delta but it was a bit of task with he old insulation.

I have a 540 which was converted to single phase by changing the main motor and the pump motor. That happened before I bought it. Works well, and its a tool I would not want to be without. If I had realised how it would transform my work, I would have bought one years ago.

It's quite a simple matter to run a existing 3-phase pump from single phase by connecting the third phase through a motor start cap. Plenty of info out there if you search for it (how many uF per kW etc). Saves having to change the motor. It will work even if you can't find the start point but even better if you can, assuming it is 415V to start with.

Murray

Murray

Yes, i did that with the suds pump on the lathe, works fine.

The problem with swapping out the motor for a single phase one, is a three phase motor is generally smoother than a single phase one, and also i believe the motors on surface grinders are very finely balanced, for as you know any little thing can affect the surface finish. There is a large motor refurbishment company not too far from me, if the motor turns out to be 440v only, i will send it to them and get them to find the star point, and then run on a VFD as normal.