[simpits-tech] AC dimmers and transformers

[Cris Harrison]

On 10/27/2014 01:02 AM, Matt Bailey wrote:
> Question: What sort of dimmer device is typically used in old business
> jets? Just a standard triac? I'm trying to figure out exactly what is
> in my Sabreliner.
>
> Second question: how tolerant are typical aircraft AC transformers and
> power regulators to variations in frequency? For instance, I have
> 115v/400hz coming off my inverter, but it breaks down to 5v AC for
> lighting (and 26v AC for other stuff). I'm wondering how critical it is
> to maintain the 400hz frequency.
>
OK I have a dimer Boeing 7xx stuff its made OECO  #200-16408-02 NSN 
5950-00-920-1174
It is a Variable Transformer 3 leads:

 1. Top or power via an internal switch
 2. Bottom or power return.
 3. Wiper or dimmed voltage to the lamps

You will most likely have to run 400 Hz as when you run lower 
frequency’s  ie. 60 Hz it will get very hot...
If I remember the cores of the 400 Hz transformers use a different metal 
in the laminations.
You have to remember that you can run lighter weight & smaller 
components at the higher frequency.
You can run 400 Hz via a 60 Hz transformer but it will /sing/. What I 
found out is that you can try audio transformers.
Enjoy
~~ Cris H


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