On 12/22/2015 10:25 AM, William Donzelli wrote:
Another thought - with scrap transformer prices in a crapper right
now. you might also be able to pick up a really beefy isolation
transformer for spare change, in order to clean up a VFD. Generally,
normal industrial grade 50 Hz transformers will not care too much if
you use them at 60 Hz.
An isolation transformer will NOT "clean up" a VFD's
output. The output of a VFD is NOT some dirty sine wave, it
is a train of 400 V PWM pulses with perhaps a 15 KHz carrier
frequency. It could be filtered, but would take a filter
built out of a bunch of HUGE inductors and capacitors. It
might actually be a decent solution for keeping
museum-quality gear running in an unaltered state, but it
isn't something you could whip up in a couple hours in your
garage.
Jon
