[Amps] Drake L-4B PSU burned resistor

[R.Measures]

On Nov 2, 2005, at 4:54 AM, Steve Thompson wrote:

>
>>> This requires a larger resistor - such as a 10W surge protection type
>>> of approximately 10 to 15 ohms.
>>
>>
>> The 10 or 14 watt ones commonly available from the big UK supply 
>> houses
>> are wire wound vitreous enamel types, with a maximum voltage rating of
>> only 500 or 750v. I guess I'll need several of these in series, not so
>> much for the power rating as for a breakdown voltage safety margin.
>> Messy, but just doable within the rather cramped confines of the L-4B
>> PSU.
> Vishay do a 'bolt down' 50W resistor which lists:
> Dielectric strength 3500V rms
> Limiting ekement voltage 1285V rms
> Maximum overload voltage 2500V rms

Sounds adequate to me for typical Ham amps.   However, my experience 
with bolt down resistors is that they act not unlike a double ended 
cannon during failure.
>
> There's overload and pulse ratings in the data.
>
> http://www.farnell.com/datasheets/1568.pdf for full data.
>
> UK price from Farnell, £2.63 ($4ish).
>
> Steve
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org