Help! Need to identify an RPM gauge

[Yak3]

Hi, we've just obtained a couple of General Aero Products Corp manufactured RPM gauges. They're electric, with a three pin Cannon plug style fitting.

Type number is ERU 7/A-1, manufacturers part number A3T-1A.

Gauge has a single needle indicating up to 4,500 RPM. The gauge face looks very similar to the standard wartime American RPM gauge, but the case is different being a simple cylinder case rather than the usual case that steps down in diameter.

Anyone have any details on this type of gauge and it's application?

Many thanks

[Cvairwerks]

Pretty modern, as it's a current production item based on a search. S-Tec builds them these days according to the NSN info that I found.

[Yak3]

Yes, fairly modern. I'm trying to see if we could use them - trying to ascertain what generator would be used with this type of gauge.

Thanks

[Cvairwerks]

3 phase synchro tachgen is what you need.

[Yak3]

Will one of the standard old generators work with it - I forget the AN number off hand, but the style as used in the T-6?

Thanks