Another day, another 'scope and more..

[djrm]

Hi
The inverter is interesting as I was asked to repair one recently with no success, it's for an artificial horizon out of an aeroplane. I believe it's 400 hz and AC outputs.

Hi David, sounds like a grand day out ! Birketts also was a good source of a/c stuff

Ferranti and others made standby inverters to work off the 28vDC supply, it may even have been a standard design. Useful bits of kit for all sorts of synchro applications

Scope looks interesting, it could be a WW design from the 70's. Most of the Mullard app note scopes were valved units


Cheers, Ed

Greetings, I was wondering if the unit would be able to supply the three phase motor of a gyro in the artificial horizon. I found a capacitor and inductor in the AC output circuits which are providing the phase shift needed to simulate a three phase supply. The photo shows a lamp load between three output pins of the inverter. One phase is much stronger than the other two but from past experience I think this would drive a motor, sweet. I'll try it on my old sperry artificial horizon. 45 watts are drawn from the DC supply in this test with three 110 15 watt bulbs connected.

   
 
The reverse engineering of the circuit and connections is coming on nicely now.
David.