3 Phase Inverter for Colchester Student

[zim]

Evening,

Well......we managed to burn out either the motor or the antique 3 phase convertor on our colchester student lathe today.

I think it was the motor, as it smells a bit down the back of the lathe.....then we were trying to start it and we fried a couple of resistors in the 3 phase convertor. It was a really old thing.

SO.....

How am i best running my lathe ? Single phase or 3 phase with convertor (or invertor, you tell me the preferred way) - which is best ?

If i went for 3 phase with convertor, is it possible to have a switch so that i could choose either A) Lathe or B) Milling machine ? (I don't have a milling machine yet, but would like one).

In a bit of a rush, so whatever i decide i'll order on Monday. Currently got a hub thats been half machined in the chuck

Thanks

Gordon

Something like this any good ? As he's local to me for collection : http://www.ebay.co.uk/itm/290735890990?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

[B reg 90]

I have a colchester triumph lathe, pedistal grinder and a bridgeport mill that I run off the same single phase 240V to 440V 3 Phase convertor/inverter. I have a 440V plug on the output that I plug the relevent machine into. Control is via a 24V signal board on the invertor that connects the relavent machine using a 7 core trailer socket. I then converted the switch gear in the lathe to switch the 24V control signal for the inverter and bypassed the contactors in the lathe. End result is the when you operate the lathe the right lever starts and stops it, the reversing lever and emergerncy stop buttons work etc. However the levers are swtiching the 24V control signal. I ment to do the same to the pedistal grinder and mill, but I just use the start stop lever on the lathe to operate the machine that is plugged in.....

Dodgy practises asside it works fine. Drives Direct do the 240 V to 440 V converter.

Adrian

[Ally V8]

I use one of these; http://www.ebay.co.uk/itm/TRANSWAVE-Static-Converter-3hp-2-2kW-Single-to-3-Three-Phase-240v-to-415v-/150965095053?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item2326388a8d

I too have a Colchester Student and I borrowed the Transwave unit from a mate who used it on a 4 post ramp. To me it was a nicer way to get three phase than running a 45hp diesel powered generator. It works very well,on higher speeds / loads you can switch in extra capacitors to balance the load.I had to swop a couple of them to start with and got hold of the makers - very helpful chaps,soon had it sorted.

[simonr]

I have a CNC Lathe and CNC Mill plus 3 Phase ramp all running off an inverter (also from Drives Direct) and they work beautifully!

I have a 3 phase filter in line as the 3 phase coming out of the inverter was a bit noisy & upset the CNC controller on the mill sometimes. The output from the filter is near perfect compared to what you would get out of a wall socket.

Unlike Zim, I just have several 3ph sockets in the workshop and treat it as if it was mains using the switchgear in the machines.

It was all dead easy to wire up. The inverter will supply about 7.5 Hp - so the input needs to be 30A at 240v which is via a suitably rated round pin connector wired back to the consumer unit. The inverter is much nicer than the switched capacitor type converters (transwave) as it doesn't care what you plug in or how many motors it's driving at the same time.

It's a good investment long term as 3ph kit is a lot cheaper than single phase on the whole.

Si

[zim]

Thanks Simon.

What would you say about the invertek unit i put a link to above. I'm tempted to go get one tomorrow if he's open ?

http://www.ebay.co.uk/itm/290735890990?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

I like your idea of a socket, would make life nice and easy.

G

[LandyManLuke]

Check the windings on the motor you're going to put the inverter on. You want to aim for a 240v delta winding so you can use 240 in, 240 out inverter. If you've only got a 400 volt winding, you'll only get to about 35hz or will need one of the step up inverters.

Have a look at inverterdrive.co.uk to compare prices.

[LandyManLuke]

Sorry, its .com.

[LandyManLuke]

Be careful, many inverters have optional keypads. You will need one to set the inverter up, so budget for one if its not included.

[simonr]

Not seen/used one of those before. Ive had a Hitachi which was pretty good and the current high power one is Siemens. Both are programmable via the buttons on the front, but both also bad a port for a screen/keyboard which would have made it a lot easier I suspect!

Si

[zim]

Cheers.

Spent yesterday machining with a 1 1/2hp single phase motor on the colchester student. Worked ok all things considered.

Before and after of one part of the job :

Then had spacers, brake discs and a big retention washer to machine.

Finished with :

Shopping for a 3phase convertor and motor tomorrow.

G

[ejparrott]

To be perfectly honest, if you've a dual voltage motor, get a 240v single phase to three phase variable speed drive. Wish I'd done it for my colchester now instead of buying a convertor. My mill is being set up this way as it's going CNC, far less to worry about, with the added benefit of figure tip speed control, which is perfect when a spindle is vibrating and you need to vary the speed to stop it - can't do that with a geared head machine!