I still balance everything manually. This works fine for smaller turbines with 54mm wheels also. You need to learn to feel the vibration but it is not to hard. Finding the right spot goes very fast now after a couple of years practice
My method:
- Mark the wheels (you do it anyway with existing turbine to align the wheels again)
- Start with the axl and turbine wheel only in bearings without pre-load ( i have the full engine on a wooden desk without the compressor)
- Add a little tape to the mark and check the difference in vibration. (i use compressed air to spin)
- Check the opposite side and the sides in between (4 point test) (If you don't notice any difference use more tape.)
You will notice that at one or 2 points the vibration will be less the other point. If you have one point it is roughly there and with 2 point it is roughly in between.
- Move the tape from the position with the least amount of vibration and move a few blades left and right to find the best point. I have about 3 blades area where the vibration is the same.
- Mark the best spot and add or remove tape to remove all vibration. If possible you have found the right spot. If not move to left or right and check.
- Remove the tape to check if the vibration is back.
- Add the tape to the opposite of the mark to check if the vibration is much worse. If so you have found the spot to grind
- Slowly grind a small part and test the vibration again. Repeat untill it runs smooth.
Btw, the machine above looks very nice but i would NEVER use a motor with band to drive the rotor. This can create small vibrations and reduces the resolution. I always use air to spin the wheels and only measure the vibration when the air is removed. When it runs down you notice several resonation points which amplify the vibration enormously. These point are very helpfull.