Thanks. I didn't know a hot wire meter existed.Here is a very unusual meter.
It is a "Hot Wire Ammeter"
It takes about 1 - 2 seconds to reach a mid-scale reading, but it is very accurate.
The pointer moves when the current heats a platinum and iridium alloy wire.
it can measure AC or DC.
It's a really cool meter ... and it's BRASS.
Hot Wire Meter
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Thanks for posting this.These are not my meters or particularly special from a collecting standpoint compared to the ones I have seen on this thread but you still might find them interesting.
The first two images show the powerhouse at the Mount Wilson Observatory being rebuilt after a fire in 1910 and the rest of the images show the switchboard as it is today inside the powerhouse. The cluster of three meters in the upper left of the switchboard have been in continuous use since then and are still being used. For those that don't know there is both a DC and an AC power system at the observatory and this is the DC switchboard.
LarryView attachment 395755View attachment 395756View attachment 395757View attachment 395758View attachment 395759View attachment 395760