The load on the (15A) Variac, as measured by an analog Watt meter, is
between 500& 1500W. I didn't have an Ammeter hooked up.
I just tried comparing readings between the Weston analog voltmeter, the
Wavetek 27XT, and a Fluke model 75 DMM. With the unloaded output of the
Variac, all 3 agree within about 0.5V from 110-140V. But when the Variac is
loaded, the Wavetek reading is significantly lower than the other two. The
Fluke and Weston track identically, loaded or not.
But this says nothing about which one is right! Looks like I need to invest
in a true-RMS DMM!
Regards, Gary Lau
MA, USA