..."No its not"... ???
Then you back that up with reference to a Vacuum Relay design ??
Apples and Kumquarts.
Switching HV with any toggle switch is an invitation to disaster. If you
can tap the Secondary, you can tap the Primary and do what Heath did.
My condemnation stands.
73, Dick, W1KSZ
On Wed, Sep 11, 2013 at 9:58 PM, Jim Thomson <jim.thom@telus.net> wrote:
> Date: Wed, 11 Sep 2013 18:37:25 -0700
> From: Richard Solomon <dickw1ksz@gmail.com>
> To: "amps@contesting.com" <amps@contesting.com>
> Subject: Re: [Amps] Clipperton-L question
>
> I actually had to check the schematic ... I couldn't believe they switch
> the
> HV side of the Xfmr, but they do.
>
> That's a terrible design.
>
> 73, Dick, W1KSZ
>
> ## No its not. Alpha did the same for years..at least a long tine ago on
> their
> smaller desk top amps. They used an OPTIONAL $80.00 spdt vac relay
> to do the job. Of course nobody bought the optional vac relay...and just
> wired it
> permanently in the SSB-higher B+ position.
>
> ## The real trick is that when you switch from CW to SSB, your typ step
> start circuit
> is non-functional..and u get one helluva surge. On my HB B+ supply, with
> the 253 lb
> Dahl xfmr, I use a multi-tech industries model 88 switch, 13 kv rated, to
> change the various HV sec taps.
> Even then, I have to 1st shut off the 240 vac primary, then change the sec
> taps, then turn the B+ supply
> back on. Then it goes through its normal step start sequence.
>
> ## Now if going from a higher B+ to a lower B+... there is no need to
> shut off the supply. I have loads
> of sec taps on the big dahl xfmr...and all that is required is to grab
> ANY two sec taps. IE: Its tapped at
> 0-2300-3900-4800-5200 vac. Since I don’t have a 2900 tap... what I do
> is use the 5200 + 2300 taps.
> 5200-2300 = 2900 vac. Problem solved. To pull that off I used a 2nd
> model 88 switch. On switch
> is wired to half the sec taps...and the 2nd switch is wired to the other
> half of the sec taps.
>
> ## On my other HB B+ supply, that uses a 10 kva, 4800 vac pole pig
> xfmr... I used a
> DPDT relay....with all contacts in parallel, to handle more current.... to
> toggle between
> one hot leg of the 240 line...and neutral. That way I can stuff either
> 120 OR 240 vac into the
> 240 vac primary. That results in either the full 6800 vdc... or 3400
> vdc.
>
> ## To get around the step start issue, I used a SPDT- CENTER OFF type of
> toggle switch to
> switch back and forth between 6800-3400 and 3400-6800. When passing
> through the CENTER OFF
> middle position of the SPDT toggle, the step start timer drops out, and
> also the big relay that
> does the actual shunting of the step start resistors. That way, whether
> it switchs from low to high,
> or from\high to low, the step start circuit always does its thing. I
> used the spare set of contacts
> on the dpdt 0-15 sec timer module, to run the amp key line in and out of.
> That way, during the 15 sec
> step start sequence, the amp cant be keyed.
>
> Later... Jim VE7RF
>
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