Thread: Advice on a lathe

Ahh yes, the bad back. I have one of those. I'm also 73 & don't have as much vim, vigor, & vitality as I once had.

's Wadkin lathe, Angus, has a pedal that you step on to lift the motor to adjust the belt. If you look carefully at the illustrations here:

http://www.turnersworkshop.co.uk/WadkinRSManual.pdf

You might deduce how it works, and make something to help your back until the right motor and controller at the right price appear. Even after you have converted to variable speed you will need to move the belt occasionally.

My 1995 Woodfast has the motor on a pivot and hanging on the belt It is rigged so that one can lift the motor and hook it in the up position, move the belt and unhook.

I have made many a bowl, start to finish, at 800 RPM on the Hegner.

Ahh the foot pedal is a good idea but i think it will take some thinking, in the meantime i like the hook idea

Hey Paul,
Firstly, it looks like I am going to have to allocate a lot more time when I come to visit you after reading all this .
We run a different electrical distribution system to you guys over there. Generally most streets have 3 Phase and Neutral, which is bonded to Earth. 240Volts between each Phase and Neutral, which is the normal house supply, and 415Volts between Phases for larger/commercial loads. So for Spankingpigeon he will need a 415Volt 3 Phase motor, and these are usually 1425 RPM, and a 240Volt VSD. The VSD electronically creates 3 Phase at variable frequency to set the speed of the motor, and these and the motors are readily available here. (check some of the threads in "Dust Collection" for recomended suppliers)
In rural areas of Aus, they run a SWER system, Single Wire Earth Return, and these can only give single phase and Neutral, but you can get two lots of it out of each transformer, so 240Volt, or 480Volt. 240Volts for the normal house load, and special 480Volt pump motors.
Hope this all helps,
Crocy.

Originally Posted by

Mainly used for end grain work like goblets. They were very popular before chucks became the norm.

A very strong way to hold something and still useful for some work.

Developed by Bruce Leadbeatter and manufactured by Woodfast as an enhancement of the earlier straight jam chuck. Besides the better grip, the advantage over the jam chuck is that the work piece can be unscrewed and re-screwed back into the chuck to be re-centred true. Was useful with classes where work had to be packed away and remounted true to axis next lesson. As says, less relevant with the introduction of jawed chucks.

Originally Posted by Old Croc

So for Spankingpigeon he will need a 415Volt 3 Phase motor, and these are usually 1425 RPM, and a 240Volt VSD. The VSD electronically creates 3 Phase at variable frequency to set the speed of the motor, and these and the motors are readily available here.Crocy.

I was confused by the above and did some looking. I found this in the Practical Machinist site:

mookins
Plastic


<dl class="userstats"><dt>Join Date</dt><dd>Apr 2009</dd><dt>Location</dt><dd>Victoria, Australia</dd><dt>Posts</dt><dd>26</dd></dl>

I haven't read the entire thread thoroughly, and it is only two and a bit years later so you may have solved this issue however I have the following to add.

Three phase systems are 415V phase-to-phase voltage. However each phase referenced back to neutral (if there is a neutral wire) are 240V.
In star/wye/'y' connection, a motor will have all three phases connected to a common junction (the neutral) and then the input to the motor comes into the other end of each phase. This is shown in the attached image on the right. The voltages to the neutral from each phase will be 240V. The formula is Vin/sqrt(3). So in this case 415V/sqrt(3) = ~240V.

If you however, wire your motor in a delta configuration, whereby each phase is wired in seried to the next, the voltage across phases is 240V. This configuration allows you to run a 240V single phase inverted with 240V three phase output. The motor will draw more current for same load but the power will be the same. In fact the current in a delta configuration is Iin*sqrt(3). So if you had a 415V/5A motor, when it runs at 240V in delta the current will be 8.7A.

Most motor information plates will detail allowable currents for each configuration.

The wiring configuration for the motor is typically done on the junction box attached to the motor itself. The motor hay or may not have instructions for the correct orientation of the terminals to achieve delta or 'wye' connections.

Some more information on three phase circuits can be had here
Three-phase Y and Delta configurations : Polyphase Ac Circuits

I hope this was clear and hope it may help others.

Ok I'm a little confused now but what i can gather Ill still need a 415v at whatever HP i want and around the 1400 rpm and then a 240v VSD at the the same HP as the motor ?

Vicmarc here. No doubts. Save, squize but Vicmarc. I have a VL300 and consider it better than Oneway and a la par with Robust but it is cast iron and not welded steel.

Originally Posted by spankingpigeon

Ok I'm a little confused now but what i can gather Ill still need a 415v at whatever HP i want and around the 1400 rpm and then a 240v VSD at the the same HP as the motor ?

I know just enough about 3 phase electricity to be dangerous. In my case I have 120 volt single phase available. I found a 120 volt 3 phase motor in a junk yard, dirt cheap. I bought a new Teco VFD that takes in 120 single phase and outputs 120 3 phase. I put a plug and wire on the input of the Teco, ran 3 wires plus a case ground to the motor and plugged it in. It goes forward, backward, slow, and fast. The magic smoke did not come out.

I deduce from Old Croc and Mookins that if you have 240 volt single phase in your shed you can use a 240 volt VFD and a 415 volt 3 phase motor to run your lathe. I think this is done by using a motor wired in the Y configuration where the center is grounded and 240 volts put to the ends of the Y.

According to Old Croc AU house wiring is 240 volts for normal household stuff with 415 for heavy draw stuff. Same as our 120 / 240 or 120 / 208 in the US. The reason for the higher voltage is that you can get twice the watts on the same size wire. At the risk of the higher voltage making your heart stop easier if you poke around where you shouldn't be poking.

Either I have missed or you have not stated what voltage you have in your shed. I did not see a 240 volt 3 phase motor listed in any that you posted but lots of 415 volt, which leads me to believe that the good deal will be a 415.

You may wish to check a motor rewinding shop to see if they have any used 3 phase motors and ask the question about using 240 V single phase and a 240 VFD to run a 415 V 3 phase motor. Or ask the sparky you will use to install the system for you. The sparky may have leads on motors and VFDs.

might give you a lead on a sparky and motor shop as he had a 3 phase motor rewound for Angus.

Delta and Y or star connections in 3 phase motors:

Sorry mate yea 240 v into the shed

Originally Posted by spankingpigeon

Sorry mate yea 240 v into the shed

From my point of view:

Easiest is 240V constant torque VFD, 240V 3 phase 1400ish RPM motor.

As advised above with local guidance: 240V constant torque VFD, 415V star / Y connected 3 phase 1400ish RPM motor.

Again with local guidance: 240V to 415V transformer, 415V constant torque VFD, 415V delta connected 3 phase 1400ish RPM motor.

Motor HP to taste, keeping in mind how much HP will the belt system you have will transmit. One can always buy a new pulley and belt system.

Post what you have: Size, and V - belt, or multi groove, or flat belt. I can look up how much HP it will transmit. No point in having big HP if it will only make the belt slip or break.

Multi groove transmits the most in more or less equal size to the others.



Cost depends on how much of a hurry you are to get the conversion done. I have had the ambition for a monster swing lathe for years. I found a scrapped cutoff saw in a junk yard and bought an arbor mounted on a swing arm, and two pillow blocks with a 2 3/8 inch shaft for 50 cents a pound. Then the 3 HP motor mentioned above, Then a 2 Morse taper tail stock from a metal lathe off ebay.

I went looking for a 24 inch pulley for the drive end of the cut off saw. I had seen big pulleys on the back of commercial laundry machinery. I found a place that repaired commercial laundry machinery and asked the owner if he had something that big. He said "like that", and pointed to one leaning against the building. I said exactly!, and he wanted to know why I wanted it. I told him and he showed me a 36 inch band saw he had set up with a VFD in the shop. He gave me the big pulley. It fit perfectly on the end of the cut off saw that held the 24 inch saw blade.

Some time later I found a 10 inch gear that fit perfectly on the other end, that is my face plate after drilling some holes for lag screws.

Later a disabled truck driving friend was complaining that he needed to cut up the frame of a road tractor in pieces small enough to get into a truck to take to the scrap yard. I cut it up for him and got two 7 foot pieces of 3/8 inch thick 3 X 8 inch high strength C channel. There is the bed.

All of this has taken 4 - 5 years. Meanwhile I have the 350 mm swing Hegner, 20 inch swing Woodfast, and the 28 inch swing light duty home made one with which to amuse myself.

Its just running a v belt, not sure what the size is i'll have a look.
As much as i would like it done now there is no real great need to hurry it.
Sounds like you have some nice lathes.

Let me see if I can clear this up a bit. In Australia you will need a 3 phase motor. All 3 phase motors in Australia are 415V (barring specialty or high voltage motors). Usually connected in Star. (below a certain HP and generally in the range we are talking about) To run from a single phase VSD the motor needs to be connected in Delta. Some motors are dual voltage. The name plate will give details like [Volts 415/240] This usually means that the six ends of the three stator coils have been brought out to the terminal box so re-configuring for either star or delta is just a matter of swapping some bridging bars in the terminal box. Easy. Some motors, however have a permanent star point where one end of each of the three stator coils is bonded together inside the motor. To connect this type of motor in delta the star point must be seperated and the three ends brought out to the terminal box. A bit of electrical know how and some specialised stuff (heat proof sleeving, varnish etc.) is needed to perform this operation. If in doubt, take it to a motor rewinder. They don't charge much for doing this. The neutral is not used in 3 phase motors (except where the motor is used as a brake, but we won't get into that) The VSD is supplied by 240V single phase (normal powerpoint) and puts out 3 phase at 240V between phases. It will draw more current than when connected at 415V but that will keep your kW/HP rating the same. The VSD will need to be the same or larger kW/HP rating as the motor.
Very generalised but basically what you will need.

Originally Posted by NCArcher

Let me see if I can clear this up a bit. In Australia you will need a 3 phase motor. All 3 phase motors in Australia are 415V (barring specialty or high voltage motors). Usually connected in Star. (below a certain HP and generally in the range we are talking about) To run from a single phase VSD the motor needs to be connected in Delta. Some motors are dual voltage. The name plate will give details like [Volts 415/240] This usually means that the six ends of the three stator coils have been brought out to the terminal box so re-configuring for either star or delta is just a matter of swapping some bridging bars in the terminal box. Easy. Some motors, however have a permanent star point where one end of each of the three stator coils is bonded together inside the motor. To connect this type of motor in delta the star point must be seperated and the three ends brought out to the terminal box. A bit of electrical know how and some specialised stuff (heat proof sleeving, varnish etc.) is needed to perform this operation. If in doubt, take it to a motor rewinder. They don't charge much for doing this. The neutral is not used in 3 phase motors (except where the motor is used as a brake, but we won't get into that) The VSD is supplied by 240V single phase (normal powerpoint) and puts out 3 phase at 240V between phases. It will draw more current than when connected at 415V but that will keep your kW/HP rating the same.
Very generalised but basically what you will need.

Thanks mate.
Thats sort of what i have come to the conclusion from reading this site and others and its nice to have it backed up buy a couple of people now.
The only thing i didn't know was about the delta and star patterns but that seems to be cleared up now cheers.
Well its of to ebay and gumtree lol

This thread now warrants this I think.


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