[Boatanchors] 3-phase for BA transmitters?

[J. Forster]

1 kW is not a lot of power. Getting 3 phase into a transmitter site could
well cost more than the transmitter. It would have cost me over $10k to
get 5 kW three phase with the line, transformer, and installation, and I'm
only about 100 feet from a 3 phase line.

IMO, such a decision is purely an economic one.

-John

===========


> 1000 watt output AM broadcast transmitters have used single phase
> 220/240VAC "forever", maybe all the way back to the beginning, so I am
> surprised to see the replies i am getting. Thanks to all.
>
> 73 de W3NU
>
>
>
> On 11/18/2012 1808, J. Forster wrote:
>> There are very good reasons for using 3 phase.
>>
>> Mostly, the power supply requires less energy storage in the filters,
>> because unfiltered 3 phase has only about 4% ripple, hence smallere
>> capacitors.
>>
>> Also, if a B+ fault happens, there is less energy to dump into an arc.
>>
>> -John
>>
>> ================
>>
>>> Hi Charles - Good question - I've got a 1950's vintage Navy
>>> transmitter AN/URT-3 that runs a 4-400 final at 100w output on 115v
>>> 1-phase - the 500w "booster" section (bigger p/s & modulator) requires
>>> 230v 3-phase. There are several other miitary surplus transmitters
>>> (500-1000w) that require 230v 3-ph for the high-power sections. Yeah,
>>> I could replace the HV supply but I really like keeping these things
>>> original if possible.
>>> cheers,
>>> Nick K4NYW
>>> www.navy-radio.com
>>>
>>> On Sun, Nov 18, 2012 at 5:13 PM, Charles Ring <w3nu at roadrunner.com>
>>> wrote:
>>>> What is there, useful to hams, that requires 3 phase power?
>>>>
>>>> 73 de W3NU
>
>