Variable Speed control for your lathe.
( Or anything else for that matter)

Earlier in the year Garry Clews from Teco Australia demonstrated the TW Series Speed Controller/Inverter which will allow a 3 phase motor (415v) to operate on single phase (240v). The Speed Controller allows a wide range of adjustments to be made to the motors operation.

The most useful adjustments for lathe operation are as follows but there are many others available.

  1. Variable speed from 0 rpm to more than twice the motors rated rpm, ie: my motor nominally runs at 1380 rpm which through the inverter can be run from 0 to approximately 3000 rpm.

  2. Forward and reverse.

  3. Variable acceleration.

  4. Emergency stop.

  5. The ability to allow the motor to freewheel to a stop or by variable braking.
The unit is approximately 120mm high, 75mm wide and 120mm deep. It contains a microprocessor and has a 3 digit display and touchpad for controls and programming.

They are sized according to the motor output and come in 3 sizes in this particular range, 1, 2 and 3hp. I bought the 1 hp as I felt that was adequate for my Nova 3000 but interestingly you can run a 3hp motor with the 1hp inverter but it will only give a 1hp output.

I had thought of using a 3hp motor that I have but changed my mind due to the size and weight of it, a bit much for the Nova motor mount, never mind the problems of getting the Nova pulley set to fit its 24mm shaft.

There is also provision for external control of the inverter. I have constructed a remote unit which gives me full control of forward, reverse, stop, emergency stop and motor speed, the latter via a simple knob (see the picture below). The green knob controls the speed, the square black button is pressed for the forward direction, the red button in the centre is reverse, the red button at the bottom is emergency stop. The small black button hasn’t been given a function as yet.

Click on an image for a larger view

There are a couple of possible problems the biggest one being the presence of dust, the inverter has a cooling fan which draws air through it when it is operating and the instructions say to keep dust and moisture away. To this end I have mounted the unit at about head height on the wall adjacent to the tailstock end of the lathe and will be constructing a hood to try and minimise dust settling on it but time will tell how critical dust entry to the unit is. I always have the dust extractor running when turning and sanding so hopefully this will be sufficient.

The wiring instructions supplied are easily followed by an electrician and the programming instructions, while reasonably complicated can be understood after a bit of trial and error. In fact most people could leave it at the factory settings unless controlling it remotely as I have done.

Teco Australia can be contacted on 02 9765 8118 or at 335-337 Woodpark Rd Smithfield.

Peter James

Back to the Articles page