[amsat-bb] KR-400 transformer wiring

[Hans BX2ABT]

Ah, I forgot about the (double compared to 220V) current being 
distributed between two parallel windings when using 110V, so that must 
be it. It's late now, but will try Monday. Cheers,

Hans


On 10/21/18 10:24 PM, Jim Sanford wrote:
> Try this:
>
> Remove the short from 2 and 5.
>
> Connect 110V to 1 and 2.
>
> Short 3 - 6.
>
> Measure output voltage.  If too low, put power at 4 and 5.
>
>
> It is possible that this would put 3 - 5 and 4 - 6 in opposite 
> phases.  In which case, you'll have ZERO output.  In this case, short 
> 3 and 4 instead of 3 and 6.  Again try power at 1 and 2 first.
>
>
> Good luck, and please share results!
>
> 73,
>
> Jim
>
> wb4gcs at amsat.org
>
>
>
> On 10/21/2018 9:12 AM, Hans BX2ABT wrote:
>> I got this old KR-400 azimuth rotor as a gift, but is wired for 220V 
>> and I need to run it off of 110V. The transformer's wiring now looks 
>> like this:
>>
>>
>>      |  220V  |
>>      |        |
>> |~~~~|~~~~|   |~~~~|~~~~|
>> 5    1    3   6    2    4
>> |                  |
>> |__________________|
>>
>>
>> If the drawing is messed up, here is the gist of it: The primary 
>> consists of two (parallel/separate) windings, one with odd, one with 
>> even numbering (3-5 and 4-6) with the center of the winding named 1 
>> and 2. Currently 2 and 5 are shorted and 220V comes in at 1 and 6. So 
>> current flows from 1 to 5 to 2 to 6 and vice versa.
>>
>> To rewire to 110V I guess I just use any of the combination 1-3, 1-5, 
>> 2-4 or 2-6. But I am just curious why the 220V wiring was done over 
>> two coils, not one? Was this factory standard or has my unit been 
>> modified with a different transformer?
>>
>> Once I get the control unit powered up it time to test the rotator 
>> and see if it needs any maintenance (probably will, because it hasn't 
>> been used for a long while).
>>
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