Mike Willis wrote:
>The relay is across the transformer primary, an AC one which activates
>a second. So far so good.
>For the EHT short problem, I have a resistor in series with the EHT.
The problem I was thinking of was when you get a trouble in the
transformer or bridge or HV caps; then the mains limiting resistors
don't get switched out.
In message <19980316102421.AAC10088@[18.104.22.168]>, Rich Measures
>> If there is a fault which draws high primary current and
>>stops the HV output rising to the value that shorts out the resistors,
>>they sit there with most of your line voltage across them until they go
>That is the idea. The resistors act as fuses in the event of a major
>circuit fault. If all's well, the 7w resistors barely get warm during the
>c. 1 second step-start.
I guess you can't mistake the fault indication, but I find it easier to
replace a fuse :-)
>>I guess it's more difficult with a single transformer as you need
>>to let the auxilliary supplies build up to operate the relay.
>- Two or more transformers act like a single transformer when the
>primaries are in parallel.
Indeed - I was thinking of the difference between a commercial amp with
one transformer for all supplies and home brew system where the
auxilliary supplies are often separate.
>>Having suffered once, I now use a fixed timer which gives a few seconds
>>delay - if there's a fault then the line fuse blows.
>A fixed timer changes only the capital investment.
True, but it's only pennies.
FAQ on WWW: http://www.contesting.com/ampfaq.html
Administrative requests: amps-REQUEST@contesting.com