Denford Software & Machines

My viceroy 280vs I have had for 15 years is on the road to being converted to single phase.Three options and I could do with some advice on please.

1/ Easy option of a static phase converter - has anyone done this on this machine and is there any power difference?

2/ 240v phase Inverter and keep the motor. I see viewtopic.php?t=3127 but cannot see if he kept the same motor. I believe I need to wire the motor into delta 240v but cannot see any connector bars or an easy way of doing this. Has anybody found a way to convert to delta?

3/ Install new 240v 3 phase motor and inverter. Is it worth putting new pulleys and belt on to get rid of the varispeed. Do I need 1400rpm motor or other? Does this have any advantage over static phase converter?

Many thanks

Mike

Sorry I can't answer your questions, mine was already running on an inverter when I got it, although I can't see why you would want to change the varispeed pullies, just leave them as is. The inverter, when used in conjunction with the lowest varispeed setting will allow you to get a lower bottom speed without slowing the motor too much and getting cooling problems.
The point I wanted to make is that according to Tony Griffiths (www.lathes.co.uk), the small motor which does the speed changes on a VS, although its dual voltage, apparently isn't up to the job when fed 240v 3 phase from an inverter. Mines got the manual speed change, so I don't know how any other users have solved this problem, or indeed has anyone else found out that it is a problem? Possibly you will have to settle for just using the inverter to do speed changes.

Richard

Hello

I have just completed a VSD conversion on my Viceroy.
Youtube: Denford Viceroy VSD Conversion
These days, VSDs are cheap enough and have significant advantages that push rotary converters out of contention.


If you three phase motor is dual voltage, changing the connections from Y to Delta for 220VAC operation with a VSD should be fine.
The motor currents and therefore the power is the same.

Thanks Dazz
Great looking machine you have there. Any idea of the pulley ratios you settled on?

I'll go down the vfd route now. Looks like the original motor can be wired delta as there are 3 wires on the n terminal.

I'm going to attempt to keep the original switch gear and rewire it to control the Vfd

Pneumatic perished kick switch is in process of being remanufactured too.

Hello

I settled on 75mm to 130mm for the poly-vee sheaves.
The linked Vee belt drive pulley was 94mm dia.

If I did it again I would go for 75mm to 150mm to give more torque. I don't believe a lathe can have too much torque.

I think you will find that by the time you discard the redundant electrical bits (eg. contactor motor overload relay) and add the new controls available on the VFD, you will end up replacing all of the protection and controls. The only original items I have retained are the door and kick micro-switches.

I am currently doing a VSD conversion on a larger lathe and the same applies. All of the electrical protection and controls has been binned.

Thanks Dazz most helpful. Will go with your sizes first on the varispeed then source some pulleys.

Motor is now running on a hitachi sj200 vfd in delta.

What did you do about the 3 phase coolant pump? I'm thinking of just using a capacitor on delta around 5uF.

Hello

I don't know how relevant my experience with a TDS is to the 280VS.
The drive arrangement looks completely different so you will need to make your own assessment of suitable pulley ratios.


The Viceroy TDS had a mechanical pump belt driven off the end of the 4-step pulley (which made it 5 step).
At some time in the past, this has been replaced by a 12VDC car window washer pump. I have driven that off a repurposed PC power supply.

Thanks Dazz

All up and running now. Will set the varispeed so that 50hz on the motor gives 1500rpm in high gear at the chuck.

Coolant pump has a 3.5uF capacitor on delta and runs fine. 260v on the capacitor side windings so could do to be around 2.5uF but will see if it gets hot after 20mins.

Any ideas if running the motor on more than 50hz will fry it?

Do you know if the tds travelling steady is the same as the 280vs. Ideally I just need to know the height from the t slot on the saddle to centre of lathe rotation. Sorry to be a pain and ask more questions.

Mike