All,
How many of you are running 240V-208V buck transformers on your 208V machines?
or, 208V machines on 240V 3-phase?
or rotary phase converted 240V line to 240V 3phase?
I checked voltages on my rotary phase setup and measure 240V, 240V, the generated wild leg is 269V no load. with a load it drops to around 260V
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I have 50 and 30 hp and get 238 238 221 from both they are toshiba E series idlers and I have no run caps.
Personally if I was you I would add some run capacitors so as to drop that third leg down and I'd also wire in one contactor that will positively lock out the start caps after startup as well as another that removes all power in the case of brownout and then call it good.
To re-iterate, that 269vac is too high most cnc equipment these days has varisters that actuate upon overvoltage in order to protect power supplies etc.
Very common for a varister to go ( at which point they present a dead short across the input mains ) so then what happens is either the unit keeps immediately blowing fuses or else you cant get the supply breaker to stay reset.
Then you call in a "tech" that doesnt know his ass from a hole in the ground and ends up you buy a new or rebuilt component for several thou $$$ when all that was really needed was a $2.00 part that's available over at your freindly neighborhood radio shack store.
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