Groups > sci.electronics.design > #462683

Re: 5 to 10kV rated gate transformers

From	Joerg <news@analogconsultants.com>
Newsgroups	sci.electronics.design
Subject	Re: 5 to 10kV rated gate transformers
Date	2017-06-02 09:19 -0700
Message-ID	<epdhfoF87v0U1@mid.individual.net> (permalink)
References	<ofifji02a2d@drn.newsguy.com> <592f1e94$0$8852$426a74cc@news.free.fr> <309fdaf8-1982-42da-95ef-792a528f3843@googlegroups.com> <ogs14k01lfu@drn.newsguy.com>

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On 2017-06-02 08:44, Winfield Hill wrote:
>   habib wrote...
>> Joerg wrote...
>>>
>>> I think Win meant regular transformers although
>>> he'll probably be open to PCB versions.
>
>> not on standard transfomer products but they
>> can do it on custom spec.
>
>   I wrote earlier that I'm evaluating CM chokes.
>   "I settled on a Panasonic ELF-21C023A.  It has
>   Lm = 1.7mH, Ll = 40uH and Rcoil = 0.08 ohms.
>   An 100kHz H-bridge running from 24V, with 1N5819
>   Schottky bridge rectifier, makes a 24.5V output,
>   into 5mA load, 23.6V at 25mA, according to SPICE,
>   for +20,-4V SiC drive.  The magnetizing current
>   (discharge / charge the bulk cap) is 66mA p-p.
>   [not bad]  My next step, play with potting and
>   a month-long 2x overvoltage test at 10kV."

That does not guarantee that miniscule destruction won't be creeping in. 
Meaning the transformer is going to be compromised after that month and 
there is no telling by how much. This is why hipot tests at the end of 
production are usually limited to a minute or less.

>   https://www.digikey.com/products/en?keywords=ELF-21C023A
>

Says "AC 250 Vrms max" which would be the rated maximum working voltage.

>   I'm preparing the potting fixture now.  That
>   will make this a custom transformer. :-)  The
>   Panasonic transformer looks well suited, with
>   thick bobbin insulating plastic, and generous
>   room for further insulation through potting.
>   Only need to handle 2.5kV to the ferrite core.
>

Even if you assume the low end of your spec (5kV) you can't assume that 
the core will always sit at exactly half between the coils. At least not 
for low frequency AC or DC. Creepage, contamination, capacitance 
difference and all that can make this voltage divider lopsided.

>   Another parameter, the coil-coil capacitance
>   is under 2pF.  Amazing, I had budgeted to 10pF.
>

It might all "work" but in a design review for a commercial product this 
would be flagged or at least should be.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Thread

5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-05-17 14:33 -0700
  Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-17 15:09 -0700
    Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-05-31 07:39 -0700
  Re: 5 to 10kV rated gate transformers "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-18 01:21 -0500
    Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-05-31 07:30 -0700
  Re: 5 to 10kV rated gate transformers oldschool@tubes.com - 2017-05-18 08:34 -0400
    Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-05-18 10:07 -0700
      Re: 5 to 10kV rated gate transformers Klaus Kragelund <klauskvik@hotmail.com> - 2017-05-18 10:53 -0700
        Re: 5 to 10kV rated gate transformers speff <spehro@gmail.com> - 2017-05-18 12:59 -0700
        Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-05-31 22:03 +0200
          Re: 5 to 10kV rated gate transformers Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-31 13:22 -0700
            Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-05-31 23:04 +0200
              Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-31 15:57 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 07:47 +0000
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-01 07:13 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 14:28 +0000
                Re: 5 to 10kV rated gate transformers Klaus Kragelund <klauskvik@hotmail.com> - 2017-06-01 07:42 -0700
                Re: 5 to 10kV rated gate transformers Klaus Kragelund <klauskvik@hotmail.com> - 2017-06-01 07:43 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-01 08:47 -0700
                Re: 5 to 10kV rated gate transformers klaus.kragelund@gmail.com - 2017-06-02 01:25 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-02 07:59 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 09:21 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-02 09:32 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 10:08 -0700
                Re: 5 to 10kV rated gate transformers Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-06-02 10:21 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 10:46 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-02 17:54 +0000
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 11:02 -0700
                Re: 5 to 10kV rated gate transformers Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-06-02 11:05 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-02 18:16 +0000
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 11:32 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 12:15 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 12:43 -0700
                Re: 5 to 10kV rated gate transformers klaus.kragelund@gmail.com - 2017-06-02 10:04 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 10:54 -0700
                Re: 5 to 10kV rated gate transformers "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-06-02 17:35 -0500
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 15:56 -0700
                Re: 5 to 10kV rated gate transformers upsidedown@downunder.com - 2017-06-01 17:44 +0300
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 14:57 +0000
                Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-06-01 08:05 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-01 08:45 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 16:07 +0000
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 11:08 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 11:37 -0700
                Re: 5 to 10kV rated gate transformers Klaus Kragelund <klauskvik@hotmail.com> - 2017-06-01 07:33 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 14:56 +0000
        Re: 5 to 10kV rated gate transformers upsidedown@downunder.com - 2017-06-01 12:08 +0300
          Re: 5 to 10kV rated gate transformers habib.bouaziz@gmail.com - 2017-06-01 04:12 -0700
          Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-01 07:15 -0700
      Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-18 20:08 +0000
      Re: 5 to 10kV rated gate transformers upsidedown@downunder.com - 2017-05-19 00:03 +0300
      Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-18 14:12 -0700
  Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-05-31 10:48 -0700
  Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-05-31 21:50 +0200
    Re: 5 to 10kV rated gate transformers Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-31 12:57 -0700
      Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-05-31 22:10 +0200
        Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-01 13:09 -0700
          Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-06-01 23:17 +0200
            Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-01 14:35 -0700
              Re: 5 to 10kV rated gate transformers habib.bouaziz@gmail.com - 2017-06-02 07:01 -0700
                Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-06-02 08:44 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 09:19 -0700
                Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-06-02 11:18 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-02 09:28 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 09:35 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 11:16 -0700
                Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-06-02 14:02 -0700
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 14:36 -0700
                Re: 5 to 10kV rated gate transformers John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-02 16:08 -0700
                Re: 5 to 10kV rated gate transformers Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-02 16:46 +0000
                Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-06-02 23:13 +0200
                Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 14:39 -0700
                Re: 5 to 10kV rated gate transformers habib <h.bouazizviallet@free.fr> - 2017-06-03 09:47 +0200
                Re: 5 to 10kV rated gate transformers klaus.kragelund@gmail.com - 2017-06-03 04:28 -0700
                Re: 5 to 10kV rated gate transformers Jasen Betts <jasen@xnet.co.nz> - 2017-06-07 20:03 +0000
                Re: 5 to 10kV rated gate transformers Winfield Hill <hill@rowland.harvard.edu> - 2017-06-08 10:12 -0700
                Re: 5 to 10kV rated gate transformers dagmargoodboat@yahoo.com - 2017-07-13 07:35 -0700
  Re: 5 to 10kV rated gate transformers Terry <respect__privacy@hotmail.com> - 2017-06-02 06:06 -0700
    Re: 5 to 10kV rated gate transformers Joerg <news@analogconsultants.com> - 2017-06-02 09:27 -0700
  Re: 5 to 10kV rated gate transformers bloggs.fredbloggs.fred@gmail.com - 2017-07-13 07:43 -0700

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