"Phil Allison"
"Keith Marshall"

( having read all the preceding posts)


** OK - I'll go for a " left of field" scenario.

The 3-phase motor of your saw is capable of generating a large back EMF
(voltage spike) when it is switched off or the AC supply is disconnected.

As the small tranny is wired directly in parallel with this motor - it
may suffer damage from even one such event. Shorted turns in the primary
being the most likely, layer to layer when in series mode as you have it.

Fixes:

1. Wire a new, similar tranny in 120 volt mode and connect it to a single
phase supply via its *own* lead.

2. Fit spike voltage protection across the primary of the tranny, ie a 270
VAC varistor or a 4 uF, 275VAC rated capacitor.

3. Attach a permanent load to the small tranny, like a 50 watt halogen
light on a goose neck.



** BTW

The 3 suggested fixes are alternatives - you will not need to do all of
them.


..... Phil