"Steve Lusardi" wrote:

3 Phase power is very desirable. Motors do not suffer velocity modulation
like single single phase motors do and they are more efficient. I am
American, but live in Europe where most homes are fed with 3 phase. It is
wonderful.

Most of us would kill for 3ph in the home. It would also make breaker boxes
for industial settings a hell of a lot cheaper.


When I return to the US, I will do my damdest to live where 3
phase is available, but having said that, I do appreciate the single phase
dilemma in the US. My solution would be a Motor Generator set where I would
run a large single phase motor and drive a 3 phase alternator with a very
large flywheel in between. These are very efficient and infinitely more
reliable than an electronic phase converter, as they are very prone to back
EMF caused switch failures with the large inductive loads. I know the
puritans in the group may flame my solution because by using an inductive
motor as a rotory source wwould create a secondary frequency 10% slow due to
inductive slip, but my experience using 60 Hz motors on 50 Hz power has
proven that it works flawlessly and it is definitly the least expensive
solution. Remember that all converters imitate the third phase, but do not
drive the motor in a balanced condition, as this manufactured phase is only
a helper.


I don't know about that slip thing but a motor / generator with a fly wheel
sure would keep the lights from dimming when you switched on your industrial
sized machine out in the back yard polebarn.

Of course that presents the problem where you start up the gen set. Having
worked with a number of mechanical die cut presses, spinning up the flywheel
is the MOAL (mother of all loads). So now you need a soft start VFD as an
input to the motor/genset. Most HSM'ers would just skip the genset and use
the VFD.


Wes