06-10-2023, 08:40 AM
(05-10-2023, 10:45 PM)Murphyv310 Wrote: 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.
(06-10-2023, 05:46 AM)ppppenguin Wrote: Is the inverter only for use on the ground (where 400Hz power isn't otherwise available) or is it also needed in the air (where standard aircraft power is 400Hz)?
Hi, Judging from another Ferranti inverter I have I'd say these are backup inverters for use when the main AC power is missing. There is a master relay to enable the output, possibly overload protection. There are also three other relays which are controlled by a single DC input which will switch over some of the AC when energised - I'm not sure how this operated yet. I have verified that the no-load output is 122 V 408 Hz where 1/2 an amp is drawn from the 26 VDC input. I'm drawing up the output the wiring first though. The unit is very nicely made for servicing and can be operated out of its casing.
There are three TO3 transistors, four TO5 transistors, five transformers, three large capacitors, four relays, and a preset resistor inside. Most of the multiple way connector terminals are connected to the relay contacts, two have AC present on them when power is applied. Here is a picture of the new frequency meter being driven from the output.
David.
