Winston writes:

Ned Simmons wrote:
On Sun, 08 Mar 2009 13:49:50 -0800, Winston
wrote:

Ned Simmons wrote:
The patient is a 1000W Yamaha EF1000is inverter generator. The 50cc
four cycle engine drives an alternator that powers an inverter which
outputs clean 120V 60Hz power.
(...)

Your variac is gonna be really reactive, power factor wise.
The inverter may be getting confused about the phase shift
between the voltage its supplying and the current demand
that follows.

It's not my department, but won't the PF of a transformer driving a
resisitive load be close to unity, once the xformer's start-up surge
has passed?

No. The current peak through a purely inductively reactive load
will continue to arrive 90° later than the voltage peak as long
as the load is connected.


It's been a long time since EE 412, Transformers and Machines. But
surely the transformer input should reflect the output, +/- 3dB [as the
joke goes...]

Otherwise, EVERY load on the grid would appear to be fully reactive to
the grid; as there's not a consumer out that who isn't fed via multiple
transformers. [132KV-13.2KV; then 13.2 to 240/120, etc]

I'd sooner blame the high speed jet...


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