VISON tool and cutter grinder.

[garyParticipant @gary44937]

just bought a vison tool grinder and wandering what my options are for driving it. it has three 3 phase motors on it and i dont have 3 phase.  has any member got one.   gary

[bernard towersParticipant @bernardtowers37738]

My that is a serious beast, it would take a while to learn all of its capabilities. Pretty good pics on Lathes .co.uk.

[Martin of WickParticipant @martinofwick]

Use an inverter drive (aka VFD).

[duncan webster 1Participant @duncanwebster1]

Steinmetz connection, worked a treat for me on a Ferret grinder. Loads of threads on here about VFD and Sreinmetz

[Martin of Wick]

On Martin of Wick Said:

Use an inverter drive (aka VFD).

On duncan webster 1 Said:

Steinmetz connection

What do we know for a fact? The machine has three number three phase motors.

We do not know what those motors do nor how they are connected (both internally and to the control circuits of the machine).

Would it not be prudent to ask for or await details of the actual motors in the machine, what they power and how the power reaches them before such speculation?

[garyParticipant @gary44937]

ok. the first motor spins the main grinding spindle it is 1/2 hp and spins at 2800 rpm.  the second motor is atached to the work head for grinding between centres it can take a 3 or 4 jaw chuck and index plates. it 1s 1/4 hp and spins at 1380 rpm, it spins in the opposite direction from the grinding wheel and is quickly detachable from the work head when not in use.  the third motor drives the suds pump which i dont think i will use.  ca.n a single vfd run two motors at different speeds at the same time?          each motor has its own three pin socket and on off switch.

[Martin of WickParticipant @martinofwick]

…prudent to ask for or await details…

No.

The question was about options for provision of a 3 phase supply to run the machine, not the precise technicalities involved with interfacing to the machine. The OP will have to decide on their level of competence and deal with that issue accordingly.

So you have in ascending order of difficulty:

Ask your DNO to provide a full 3 phase supply to your house.

Or

Use the type of VFD to synthesise 3 phase output that will run on standard 220v single phase voltage input and provides a 380v 3 phase output. Having more than one motor running at any time may mean more that one VFD.

Other solutions are available, but will rely on reconnecting the windings from star to delta, which may not even be possible if the star point is buried in the motor. Even if the motor is reconfigurable to delta, I would prefer a 220/220 VFD to deliver a synthesised 3 phase output. Using the capacitor ‘kludge’ on one of the coils will allow the motor to function of course but at the cost of reduced toque and/or power.

All of the real world issues such as feasibility, safety, interference, legality, operability, connectability, cost, etc. not discussed here.

[Martin of WickParticipant @martinofwick]

You will most likely need a VFD for each motor if you wish to run both motors at the same time.

To understand what type of VFD, You will need to know what the motor characteristics are. That is the details on the plate… operating voltage, current, whether it is declared as dual voltage (not always stated, but can sometimes be determined from looking at the connection box on the motor and checking to see if all 6 wires are available).

[noel shelleyParticipant @noelshelley55608]

Why has no one considered the most obvious solution to running 3 motors, a static or rotary converter ? Simply plug in and run – no star / delta conversion, contactors with 415v coils will work. Transwave come to mind, I use one on a Brierley and Clarkson.  Noel.

[Martin of WickParticipant @martinofwick]

Noel is right RPCs are a viable solution, but for some reason I tend to think of RPCs as being yesterdays solution – a large, expensive, inefficient, noisy box.

However, if you have space for one, preferably not in the room you are working in, an RPC might be cost effective and robust solution against multiple VFDs, with two or more motors to run. I think Transwaves deliver up to 415v, and you can make up your own 3 phase supply fused board fairly simply, will be about £1k for a plugin solution. Not as many control options as VFD but probably not that relevant for a grinder.

Depends on level of comfort with digital vs analogue world and whether you are likely to acquire more 3P equipment.

[Martin of WickParticipant @martinofwick]

If you want more choice, static phase converters are another option, but they are usually load specific and even adjustable ones may be a bit awkward to operate when switching between single and multiple motors.

[noel shelleyParticipant @noelshelley55608]

The whole point of a static converter is that it is 415v using a transformer then capacitors to create the 3rd phase, a single control balances the system for load.3 motors that don’t top 1.5Hp in total a static IS the answer – or Plan B, Living in rural England and there being NO 3 phase in the area I coupled a 3Ph alternator (20Kva) to a peugeot diesel engine to generate my own Real 3Ph – it opened up a whole new world !  Big welders and Huge electric motors ! Noel.

PS I know there not cheap but there pretty near bomb proof !

[Martin of WickParticipant @martinofwick]

I always thought there was aprox  30% power loss with  static converters as well as needing to respect the minimum load requirements and other issues?

Anyway, for the benefit of the OP, the Transwave site has useful info to help decide on approach (other suppliers / makes of converter are available).

[garyParticipant @gary44937]

thanks for all the replies lads, certainly a lot to consider. surprised no one suggested simply changing the motors.

[Martin of Wick]

On Martin of Wick Said:

You will most likely need a VFD for each motor if you wish to run both motors at the same time.

Are you sure? A VFD should handle variable loads just fine. They handle overload by dropping the frequency, and of course that can cause problems depending on the application. But in this case it might work, assuming we’resimply switching two smaller motors while the main motor is running and there is no sensitive electronics to consider.

If you think about it this really isn’t too different to normal operations. The only difference is that instead of a voltage drop you get a frequency drop (OK, perhaps both). And it won’t shock the VFD either, it’s switch mode so it’s in perpetual shock  🙂

[Martin of WickParticipant @martinofwick]

Weeell in theory that would be right, I didn’t say you cant run multi motors off a single VFD, just don’t think it would be desirable to run a mixture of powers and pole Nos, especially on a grinder where you are looking for consistency and may not want to have your RPM varying. Ignore the suds motor, which can be bodged up with a capacitor to run on single phase if required. The main 350W grinder motor will be most often used singly,  unless much cylindrical grinding is to take place. So if two motors are run only rarely, it might be worth a punt on a single VFD but may loose out on some protection features for the smaller motor (which as it is a low torque application is not such a great risk).

Gary, single phase motors not suggested probably because we are all secretly addicted to the smooth effortless power of three phase motors. The very idea of replacing a good 3P with some vibrating, balky, anemic dross just does not compute.

However, we are broad minded here, so if you want to go down that route, a couple of hundred £ will get you a couple of new  single phase TECs of suitable size. Or you can scour the online markets for S/H. I very much doubt you will find any to be a drop in fit, so be prepared to make up mount adapter plates and re-drill or shim pulleys, adjust guard mounts, belt lengths etc.

[Author]

Posts