[TowerTalk] [Amps] Bill Orr comment

[jimlux]

chasm at texas.net wrote:
> Peter Voelpel wrote:
>> 2-2.5 times the dissipation is normal. 
>> Assume 1500 out, at 70% efficiency that is 643W dissipation, 1500/643=2.33.
>> Eimac claims 75% efficiency on their 3CX3000A7 datasheet in AB2.
>>
>> 73
>> Peter
>>
> 
> 
> I am sorry but I do not understand your numbers
> using my Construction Master IV
> 
> I multiply 1500 by 70% = 1050
> 
> after all, 50% would be 750.
> 
> please explain to this old phart what I am missing here.
> 

Percentage the wrong way..

DC power in = RF power out/efficiency
Power dissipated = DC Power In - RF power out

1500/0.7 =2143
2143-1500 = 643W