Hi Brad,
First I read about the PMH here:
http://www.keelynet.com/energy/emery.htm What was strange for me is that Matt Emery placed the Ammeter directly onto the top of the transformer core. See the photos on his setup near the very bottom of the link by scrolling down.
When the meter is placed onto the wooden table (photo on the left), the needle is just in the center zero position as it should be (that meter has a center-zero mechanism, the zero Amper is in the middle of the scale).
He happened to place the meter onto the top of the transformer core and when he switched off the charger, the needle still showed 6 Amper current.
For me this means he was not aware of the sensitive nature of the magnetic balance such moving coil meters have in order to operate properly. To have a linear DC scale, a homogeneous magnetic field should be maintained in the gap where the moving coil turns and deflects the needle. When this magnetic field is influenced or disturbed from the outside as it surely happened in Matt's case from the very closeness of the iron core of the transformer, the needle did deflect without any current. I found this behaviour with my such analog meters too.
So to say the least: there was no 6 A current flowing through the meter (hence no current in the circuit) when he disconnected the cables as he wrote. Should he has lifted up the meter from the top of the transformer core, the needle would have returned to zero.
Please watch these two videos, maybe you have seen them: Transformer core tests, Part 1 and 2 and confront it with the PMH. Part 1:
https://www.youtube.com/watch?v=SHbQXnXK6Xc Part 2:
https://www.youtube.com/watch?v=BsN2sr3U0PY What I think of the PMH: until further proof is shown on the contrary, it "works" due to remanent magnetism in the core.
I think that so called magnetically good soft irons like ferrite or hipersil cores, when they are in a magnetically closed circuit, will have their domains maintain in the direction the huge input current pulse sets them. Notice I write 'huge current pulses', meaning several Ampers like 6-10 A or higher because if a PMH has 1-2 Ohm coil winding and excited from a 12 V battery, about that high currents will be involved, this can be a heavy "shock" for the domains.
And when the keeper is removed the domains can return to their earlier position i.e. the core becomes unmagnetized (and the coil on the PMH senses the rearrangement of the domains, in the form of kinda flyback pulse). With ferrite or hipersil cores a PMH may not be able to keep magnetism as long as say a PMH made of normal transformer lamination or steel or cast iron can.
Gyula