Hi Gary, no, positive it is for 60Hz
----- Original Message -----
From: "Gary Smith" <Gary@doctorgary.net>
To: <Amps@contesting.com>
Sent: Wednesday, February 11, 2009 11:46 PM
Subject: Re: [Amps] Transformer heating (problem?)
> I'm sure no expert, any chance the Iron's not built for 60Hz?
>
> Gary KA1J
>
>> Corollary to a previous issue with a B+ transformer I passed thru the
>> group a while back, which before I repaired it had a current loop due to
>> bad/no insulation on the core bolts. Transformer has a 240V primary,
>> 2800-3000V secondary rated at 2 amp CCS. Is installed & in use on a HB
>> GS35b 6m amp. When "module" testing the amp the transformer taps met
>> specs, measured with a Simpson 260. Calculations based on measurements
>> then indicated a 12.5 to 1 ratio.
>> Fast-forward to completed amp...After some occassional use (~30
>> minutes of total operating time) am having the following "issues." The
>> 3000VAC secondary tap is now only putting out 2700VAC with line voltage
>> measured at 243VAC (240V mains line is 10 guage wire, a 10 ft run from
>> the breaker box & then 6 feet of 12 guage line to the amp... original
>> measurement taken with same lines). The even more disconcerting problem
>> is that after a couple hours of sitting at "idle" (amp on, power to B+
>> but no RF) the transformer iron is getting hot- enough that you wouldn't
>> want to keep your hand on it for long, and particularly so near the left
>> & right sides of the core. (Yes, I checked the plate meter & no current
>> thru tube, bias relay fine).
>> Lamination bolts remain cold so no more current loop around the
>> mounting brackets.... I am baffled as to why this thing is getting hot
>> just idling. There is no "bleeder" per se on the PS, just 6 x 220k ohm
>> Rs across each of twelve 450V caps in series. The only other constant
>> current draw is a 5 MEG dropping R to the B+ meter. I am baffled as to
>> why the transformer laminations would get hot with almost no current
>> draw, and am concerned that once I really work this thing out during a
>> contest or Es opening the heat is going to short the secondaries.
>> Any ideas as to what could be going on? Is this normal, or as I am
>> beginning to think, an 86 lb misdesigned piece of junk??? Any input
>> appreciated.
>>
>> 73 Dave N3DB
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|