woodturning lathes

[gezzer]

Ey up !
I have just acquired a Viceroy Educator wood turning lathe (ex-school use), this will replace my home-made lathe (if I can generate enough space in my overloaded garage) . The only problem is, it has a 3 phase 0.75 H.P. 400/440 V motor (made by Hoover, circa 1962). I have been looking at variable frequency inverter drives on the web, but the range available is vast. I was wondering if anyone has any recommendations for one of these units to suit my needs, which would apparently give speed control as a bonus. Alternatively, do you think replacing the motor with a single phase item is a better idea. Any suggestions would be appreciated.
Thanks in anticipation,
Gezzer.

 

[TFrench]

Inverter drive is great, well worth the effort over a single phase motor. I can't recommend a specific inverter, but I can say DON'T get a bosch rexroth one - I did and its totally unsuitable for using on a lathe!

 

[graduate_owner]

Well now Gezzer, I did exactly the same thing and I think the Viceroy is a really solid piece of kit. Mine came with a Hoover motor too, rated 415 volts so not dual voltage ( which you need for use with an inverter). I had a spare dual voltage motor and already had an inverter so to replace the Hoover was a no brainer. BUT - it was a bit of a palarver when it came to actually, physically replacing it. In the end I lifted the entire motor end of the lathe with a winch and dropped the old motor plus mounting plate to the floor - motor plus cast iron mounting plate = quite heavy. Then I just bo!ted the new motor to the mounting plate and lowered the lathe back down. Took a bit of fiddling to line up and get at all the bolts, but do-able.
So, do you have a suitable 3 phase motor? If not then you have 3 options -
1. Buy a 3 phase motor and inverter which will give you variable speed
2. Buy a single phase motor.
Both of these options mean the change motor performance, obviously
3. Buy a 3 phase converter and use the existing Hoover motor. You won't get variable speed though. Also the cheaper static converters will give an approximation to 3 phase but you will only get about 60% of the rated power output of the motor. The dearer rotary converters are a better approximation but can be a bit noisy with their motors running all the time.
Like I said, the choice was easy for me. I do like the lathe - dovetailed slides on the banjos, solid cast iron bed, I think it is real quality.
If you decide to go down the inverter route, let me know and I will get the details of my inverter for you - seems to work fine for me with default settings, and I just plug in other machines when needed with no need to change any settings.

Have fun.

K

 

[Inspector]

I just received a Variable Frequency Drive (VFD) to power my 5 hp 3ph dust collector. I wanted the option of running it slower for light dust producing activities. I bought it through Alibaba from Dalian Powtran. Total cost to me in Canada was $225US and it took about 2 weeks to get. Find them on Alibaba and ask them what one would cost giving them as much information as you can. They have a number of versions that input single phase and output a number of 3 phase voltages. I needed a 4 kilowatt unit so you would need a .75KW VFD. One nice thing about this drive is the control panel can be removed from the unit and with a Cat 5 cable that was supplied let you mount up to 6 feet from the VFD. It isn't quit plug and play so you will need to program the parameters of the VFD. Find a good sparky to help.

Pete

 

[graduate_owner]

Mine is an Invertec Optidrive, from a UK company. You can find them on ebay. I deliberately avoided far east imported ones.!!!
If you do decide on a vfd, then you need to consider the issue of dust and moisture. I had a Eurodrive vfd which went defective and it just had a fan and ventilation slots which I suspect caused the problem eventually. The optidrive is available as a totally enclosed IP 54 or whatever, or as a cheaper but open ventilated model and the instructions specifically state not to be used in a dusty or damp atmosphere - didn't know that when I bought it. Anyhow it is mounted inside a home made steel cabinet about 30" tall, plenty of room for air to circulate. There is a thermal cut out wired in to the supply, set to operate at 50 degrees, and I have recently bought a cheap (£2) moisture absorber - the type used for caravans etc, to put in there with it. Because I can't easily get at the front control panel now, I have a lead going to a box with speed control, on/off and reverse switches connected. Magnets glued to the base of the box allow me to position it easily on any of my 3 phase machines.

K

 

[SteveF]

Mine came with a Hoover motor too, rated 415 volts so not dual voltage ( which you need for use with an inverter)

sorry to contradict, my ags10 tablesaw is 415v
myfordman of this parish sorted me an inverter, without me changing motor wiring

Steve

 

[graduate_owner]

Most of the inverters in the sub £300 range produce 240v so the 3 phase motor needs to be connected in delta mode. You can indeed get 415 volt output from inverters, they have a built in transformer, but are more expensive. Worth it though if it means avoiding changing the motor. I already had a 240v inverter for other machines so it was better for me to change the motor to a dual voltage wired in delta mode rather than get another inverter, even if it was a right palaver.

If I had known about 415v inverters before I was committed to 240v 3 phase then t would have saved me a lot of messing about - I have now had to change 3 different motors because they were star connected only.
K

 

[Inspector]

A star wound motor can be changed to delta by opening the motor a changing the wires in the windings. A motor rewinder can do it. Whether the cost to do the change is cheaper than a replacement has to be factored.

 

[graduate_owner]

I happened to have some dual voltage motors so it was easy enough to just swap them over ( apart from the Viceroy). I had to take one to a motor repair / rewind firm though because it was an awkward mounting arrangement. It cost me £35 about 9 years ago to have it done. I bought an inverter about 11 years ago. They were not so common then and I didn't know that 415v ones were available. So kind of committed to the delta connected 220 volt now.

K