[MIPS]

Okay. The damn things arrived in the mail. Both using Ebay's Global Shipping Program and both the polar opposites of what you would expect of "well packed"




Okay, so two identical units. One setup for 50p coins and the other setup for pound coins. The terminals are like I've seen with older postwar KwH meters here in North America where it's terminals for four beefy wires.



Everything is screwed shut with fasteners that let you put wire and lead crimp seals on them. The coin box also has an additional post for a padlock. When you take the coin box out you can remove the lock ring on the coin dial and that comes out as an assembly. I'm assuming this is how you interchange coin types. The coin acceptor has no sort of a protection against slugging beyond it goes into the coin box and your landlord busts you when he goes to empty it. The 50p one will take a Canadian Loonie. The 1P unit will fit a Canadian quarter with a tiny amount of filing. The correct coin pushes down a spring loaded plate which extends a catch. Then as you turn the knob a gear in the back of the cavity turns and this adds "units" to the meter and advances the coin counter by 1. The coin acceptor is notched around the edge so that you can control how many units of energy you are paying for, then use the lock ring to keep it set.





When the unit counter is greater than 0 a contact is closed and AC power is allowed to flow through the meter from the LINE side and out to the LOAD side. The mechanical assembly for counting units paid for and the contact mesh into one of two gears on the meter side and by turning one screw lets you set between two fixed rates, depending on how much or how little energy you want to make people pay for.





The meter side is just a plain old mechanical KwH meter where the lower coil is for the main load and the upper coil (I guess it's called a Field winding) just has the line voltage as reference. Supposedly this is the part you have to tweak if you ever wanted to run this at a different AC line voltage but the line frequency is fixed.