I've got a Kill-A-Watt and have been monitoring and adjusting the Metro for 61 Hz unloaded. But I wasn't able to control the voltage with the potentiometer on the front of (what I believe is) an AVR.
My instructions say nothing about any AVR shipped with the ST-5, but there it is anyway.
I'm attaching photos of the terminals outside the doghouse and inside. I believe that AVR came connected properly for 240 V but incorrectly for 120V , but I wanted to check that out with you all.
If you look at the external terminal photo here you see a connection diagram showing where to place two jumper lugs for either 120 or 240. In the photo the lugs are on the 2 center terminals for 240 operation.
If you measured across the two outermost terminals (U1 to U2) you'd get 240V If you measured across either the right (U1 and U6) or left pair of terminals (U2 and U5) you'd get 120V.
For 120v operation the jumpers are placed on the two outer pairs of terminals, per the diagram and then you get 120 across the pairs. Basically you're paralleling output.
Now lets look inside the box.:
The AVR is the blue box on the left. On the right are the terminals. The AVR has two thin wires coming out of it that go to the bottom two terminals. One is black and one is red.
Here's a close-up:
The two thin wires are on the right, connected between U1 and U6.
As a guess, these are sensing wires that monitor the voltage, and when the generator is configured for 240V operation, these are on one leg, and will see 120V.
However, if the jumper lugs are re-configured to give 120V, U1 and U6 are tied together, and the AVR will see zero volts (I believe). And the AVR won't work. Right?
That's what I think happened in my case when I configured the genhead for 120V. Adjusting the AVR had no effect on output voltage. When I re-configured for 240 volts, the AVR adjuster worked.
So my question is, If I want to configure for 120 V, should I also reconnect the AVR leads across the 120 V output - U5 to U6?
Thanks!
ps. (U5 to U6 would seem a better choice than U1 to U2 in case it was reconfigured as 240 V without remembering to re-connect the AVR as itwas before. The AVR would see 0 volts instead of 240, which might blow it.).