Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v53EN419017842 for ; Sat, 3 Jun 2017 16:23:05 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dH9tY-0006uh-IH for rs_out_1@blacksheep.org; Sat, 03 Jun 2017 15:19:12 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dH9tX-0006uY-K2 for rsgb_lf_group@blacksheep.org; Sat, 03 Jun 2017 15:19:11 +0100 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1dH9tU-0004cx-5P for rsgb_lf_group@blacksheep.org; Sat, 03 Jun 2017 15:19:10 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id E8C8420461 for ; Sat, 3 Jun 2017 16:19:06 +0200 (CEST) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3wg39P6SDXzyqC for ; Sat, 3 Jun 2017 16:19:05 +0200 (CEST) Message-ID: <5932C559.8080402@posteo.de> Date: Sat, 03 Jun 2017 16:19:05 +0200 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <15c6e436e71.marcocadeddu@tin.it> In-Reply-To: <15c6e436e71.marcocadeddu@tin.it> X-Scan-Signature: e76796a7cdd5c967684a5a09aa90ab76 Subject: Re: R: Re: LF: Re: I: Fw: For today the FETs survived... Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.75 Status: O X-Status: X-Keywords: X-UID: 11863 Hi Marco, If you like, i can help you. Just need a schematic to see what you want to do. Targer power, voltage, etc... 73, Stefan Am 03.06.2017 16:02, schrieb marcocadeddu@tin.it: > Hi Alan, Andy, Chris, > > I replaced the caps in the output LC with WIMA FKP1, the 2 caps wich > replaces the missing half of the bridge are still Cornell Dubillier > 940C serie (rated at 9A @100kHz), so now all the caps are pulse rated > but... > I regret to admit it, nothing changed :-(( > Power out increases from 10 to 30Vdc and at 40Vdc after a first pulse > the power slowly decreases till a couple of watts.. > > Just to check another thing: being the coil of the guard circuit > disconnected, I jointed the 2 coils together (they are wound on the > same support) increasing so the inductance of the L (25T more). Of > course I had to retune and now I need C in the range of 5000pF but this > narrowed the 3dB bandwidth of the LC from abt 15kHz to abt 8kHz so is > the Q increased! > > ... I should visit Decathlon and look for a fishing rod! > > your sincerely depressed IK1HSS > > ----Messaggio originale---- > Da: alan.melia@btinternet.com > Data: 2-giu-2017 15.58 > A: > Ogg: Re: LF: Re: I: Fw: For today the FETs survived... > > Hi Marco, I may well be wrong I was experimenting with 150W at 35V I > measured 12 to 15A through the capacitors (from memory) .......the > confirmation is that the change is permanent. I dont remember seeing > any > heating effects. Single ended Class E may be considerably different to > H-bridge. The currents a lower power will be less, about 1.5A or so > (??) I > am not sure it that would produce damage, but you would certainly see > it as > the power increased. > > Good Luck with it > Alan > G3NYK > > ----- Original Message ----- > From: > To: > Sent: Friday, June 02, 2017 2:00 PM > Subject: R: LF: Re: I: Fw: For today the FETs survived... > > > Hi Alan, > > and thanks for joining :-) > it's hard to believe at this stage that is correct to speak of "high > currents".. > The PA is an half bridge like > Andy's 700W but now I'm testing at low voltage: I see these problem > trepassing the 30Vdc supply level (and power is about 15W).. > Anyway will try with the "pulse rated caps" you suggested just in case > my "low current" "low tension" ideas are wrong. > 73 Marco > ----Messaggio originale---- > Da: alan.melia@btinternet.com > Data: 2-giu-2017 14.36 > A: > Ogg: LF: Re: I: Fw: For today the FETs survived... > > Hi Marco I dont know where you are putting the caps but I am assuming > they > are passing a high RF corrent. I found that the old style (valve) high > voltage caps in my Class E test rig changed capacitance permanently > during > and after a run (capacitance reduced). I assumed that the current was > fusing > the foil connection to the lead-out wires. When using "pulse rated" > capacitors as used in SMPSUs I had no further capacitance change > problems. > The ones I have are RIFA PHE 428 2000v from RS Components. I think > Farnell > do a WIMA equivalent. > > Best Wishes > Alan > G3NYK > > ----- Original Message ----- > From: > To: > Sent: Friday, June 02, 2017 1:06 PM > Subject: R: Re: Re: Re: LF: Re: I: Fw: For today the FETs survived... > > > now my thoughts are even more confused.... > Hi Andy, me again.... > after a long night of meditation, I remembered I had a bounch of old > style mica capacitators 1000pF 1000V.. > I put > 9 of them in parallel to get the closer value to the 8800pF I had > before. > Of course the resonance moved a bit and now is on 134.5 kHz with 3dB > bandwidth of 9 kHz (Q=15 I know is a bit to high..) so carried out some > tests on 134 kHz (of course on the dummyload) all without guard circuit > 1st test xfmr 7T/19T (Ae197mm² R50 mat T38): 2Wout @10Vdc; 6,5 > Wout@20Vdc; 13,7Wout@30Vdc stable.. @40Vdc after a quick peak the power > slowly goes down till below 1W! > 2nd test I had still on hands the previous xfmr 5T/12T (Ae197mm² same > core as 1st test) so was worth to make a trial... same trend :-( for > Vdc> 30V after a first peak... it goes down. > I had another core available with different material (N30, Ae 154mm² > R58) so I prepared a new xfmr with this core 7T/14T: > 1,4Wout@10Vdc; 4,6Wout@20Vdc; 9,2Wout@30Vdc .... at 40Vdc a short burst > with almost 15Wout and then down down down... :-(((((( > > I noticed a difference in comparison to your project: you connected the > + and - rails to ground via 10nF and here I used 100nF caps could it > explain this behaviour? > > 73 Marco > > ----Messaggio originale---- > Da: marcocadeddu@tin.it > Data: 1-giu-2017 22.20 > A: > Ogg: R: Re: Re: Re: LF: Re: I: Fw: For today the FETs survived... > > that was also my thought.. but they run at room temperature: the > resonance is obtained with 4 polyesther 2200 pF 2000 Vdc caps. the > classic boxes 25x15x5mm > > Marco > > ---- > Messaggio originale---- > Da: andy.g4jnt@gmail.com > Data: 1-giu-2017 22.03 > A: > Ogg: Re: Re: Re: LF: Re: I: Fw: For today the FETs survived... > > If the conditions change as the PA is operating, it looks like > capacitors > heating up and changing its value. I can't think of any other > component > that will change with dissipation / heating. What type of capacitor > are > you using in the tank? > > Andy > > > On 1 June 2017 at 19:59, marcocadeddu@tin.it > wrote: > > >> anybody has good ideas for a replacement hobby?? fishing? growing >> flowers? >> >> Andy: the suggestion of try without the guard circuit revealed that >> some effects in this area are present. >> >> I left the guard coil in place (I'm a bit lazy...) and disconnected >> simply the 2 wires from the rectifier bridge. >> The output improve of about 4dB with Vdd from 10 to 30V, the output >> > is > >> stable up to 20Vdd, on 30V it show a peak of 16W, then the output >> starts to decrease till a couple of watts :-( this happens also at 40 >> and 50V. >> The resonance of the output LC (with the guard coil open) shifts from >> 137 to 140 kHz and the bandwidth decreases from 20kHz to 10 kHz. >> >> I need a long weekend of meditation... >> 73 Marco IK1HSS >> >> >> ----Messaggio originale---- >> Da: marcocadeddu@tin.it >> Data: 31-mag-2017 21.05 >> A: >> Ogg: R: Re: Re: LF: Re: I: Fw: For today the FETs survived... >> >> Andy.. you are almost better than online help desks :-D >> >> yes the guard circuit is on place but no current is flowing toward >> > the > >> PA, testing disconnetting it needs just to warm up the iron ;-) >> >> the PS should >> provide enough juice for 1200W input and the IRF460A are rated for >> > 20A > >> @ 25°C (13A @ 100°C) so.. I admit it would like to give a try ;-) >> >> I don't guess the core is saturating specially at this power level >> where rms is only 22V, the core is 50mm OD and has 195,7 mm²Ae: if I >> am >> not totally wrong B should be< 0,03T @50V with 7 turns on the >> > primary > >> Will tru to disconnect the guard circuit just in case the squirrel is >> running in its cage ;-) >> >> Thanks again for assistence >> >> Marco IK1HSS >> >> >> >> ----Messaggio originale---- >> Da: andy.g4jnt@gmail.com >> Data: 31-mag-2017 20.39 >> A: >> Cc: >> Ogg: Re: Re: LF: Re: I: Fw: For today the FETs survived... >> >> 7:19 turns (assuming 50R output) means you have a load resistance of >> 6.8 >> ohms which for 180V DC (81 V RSM fund sine) is nearly 1kW I don't >> think >> you really mean to go that extreme do you? 13 ohms is more >> realistic. >> >> As for the tank resonance changing as power increases, that is very >> wrong. >> I wonder if the transformer is saturating. Not sure of your core >> > Ae, > >> but >> lets assume 200mm square, a core of about 16mm diameter. >> >> V = 4.44.F.N.A.B Plugging in 137kHz 7 turns, 200 mm^2 and a Bmax >> > of > >> 0.1 >> that suggests 85V RMS. >> Which is exactlyly what you have. I suggest more primary turns . >> Before >> a transformer ratio of 1:2 was suggested, for Rload = 13 ohms >> >> Is the guard circuit in place ? Don't forget, it has to be >> customised >> to >> you exact currents and coil Q. Get teh PA operating to its proper >> settings >> foirst - that you can do at low voltage power, it scales perfectly. >> Only >> when it it working properly can you add and set up the guard circuit. >> >> When I did teh 700W PA, I had a complete workign (albeit unreliable) >> unit >> before even thinking of teh guard circuitry. >> >> Andy >> >> >> >> >> >> On 31 May 2017 at 18:50, marcocadeddu@tin.it >> wrote: >> >> >>> Hi Andy... me again... >>> >>> I was so curious to see what could happen thatI had a very quick >>> dinner and connected all, but... >>> >>> now the output xfmr has 7T/19T here my >>> readings/calculations: >>> (see attached picture) >>> again the power increase from 10 to 30Vcc then from 30 to 50Vcc >>> > after > >>> an initial burst it start to fall down.. >>> I checked also the resonance of the LC: till 30Vcc is tuned on 137 >>> >> kHz >> >>> with a 3dB bandwidth of 20 kHz, when I move to 40 and 50Vcc the >>> "maximum" output shifts to 165 kHz... >>> >>> mumble mumble >>> >>> I tempted to have roasted FETs for dessert and see what happens at >>> 180V! >>> >>> Marco, IK1HSS >>> >>> >>> ----Messaggio originale---- >>> Da: andy.g4jnt@gmail.com >>> Data: 30-mag-2017 23.50 >>> A: >>> Cc: >>> Ogg: Re: LF: Re: I: Fw: For today the FETs survived... >>> >>> I've just looked again at the circuit diagram you sent - on there >>> > the > >>> values are different from your statement in the email. It shows >>> primary 5 >>> turns, secondary 12 turns so a load resistance in the order of 9 >>> > ohms > >>> which >>> is rather low if you are intending a Vdd of 180V - but closer to >>> > the > >>> ideal >>> Rl >>> >>> The tank components have a reactance of 130 ohms which is too high >>> > a > >> Q >> >>> is >>> used with that 9 ohms Rload, You should be aiming for a Q in the >>> >> region >> >>> of >>> 6. >>> >>> Even with the optimum load R of 13 ohms described last time for 500 >>> Watts >>> from 180V rail the resulting Q of 10 is a bit too high - you will >>> > end > >>> up >>> with high voltage and critical tuning >>> >>> Andy G4JNT >>> >>> On 29 May 2017 at 19:07, Andy Talbot wrote: >>> >>> >>>> Yes. >>>> As you'll see in my original write up, I originally forgot that >>>> > the > >>> peak >>> >>>> of the fundamental sine component of a square wave is GREATER >>>> > than > >>> the peak >>> >>>> by a factor of 4 / pi and initially my PA delivered a lot more >>>> >> power >> >>> (1.6 >>> >>>> times) than it was supposed to. >>>> >>>> So if the square wave has a peak value of 1, its fundamental sine >>>> component has a peak value of 4/pi or around 1.27. The RMS of >>>> > the > >>>> resulting sine is SQRT(2) less than this giving a Peak square to >>>> >> RMS- >> >>> sine >>> >>>> ratio of 0.9.. If you specifye peak-peak of the square wave, a >>>> >>> further >>> >>>> factor of 2 applies, leading to the 0.45 ratio described before. >>>> >>>> Incidentally, this same ratio appears in that equation for flux >>>> >> in >> a >> >>>> magnetic code, V = 4.44.F.N.A.B >>>> The magic number 4.44 is actually SQRT(2) * pi and comes >>>> > about > >>> from >>> >>>> the same sort of sine to square transform. >>>> >>>> Andy >>>> >>>> On 29 May 2017 at 18:48, marcocadeddu@tin.it>>> > it> > >>> wrote: >>> >>>> >>>>> uhuh... a slightly silly misleading assumption... Vdc are the >>>>> > same > >>> of >>> >>>>> Vrms before FETs make their work! >>>>> >>>>> Thank you Andy for pointing out it!! >>>>> With this approach calculation changes a bit and probably with >>>>> > the > >>>>> right Xfmr the PA can give higher satisfaction :-) >>>>> >>>>> Hopefully the FETs will survive and this time I'm ready to >>>>> > burnout > >>> the >>> >>>>> antenna hi >>>>> >>>>> Will keep you both updated, thank you once more Andy >>>>> >>>>> 73 Marco, IK1HSS >>>>> ----Messaggio originale---- >>>>> Da: andy.g4jnt@gmail.com >>>>> Data: 28-mag-2017 21.18 >>>>> A: "marcocadeddu@tin.it", >>>>> >>>>> Cc: >>>>> Ogg: LF: Re: I: Fw: For today the FETs survived... >>>>> >>>>> First thing I noticed is that your turns ratio on the output >>>>> transformer >>>>> doesn't look right. >>>>> You quote "* ... with primary winding of 15 turns and secondary >>>>> > of > >>> 12 >>> >>>>> turns...*" >>>>> >>>>> 180V DC in a half bridge is 180V peak-peak square wave. >>>>> The fundamental sine part of that is 4/pi * 180 = 229V pk-pk >>>>> so is 229V /[2.SQRT(2)] = 81V RMS >>>>> >>>>> To a good approximation RMS(fund) from a half bridge is Vrms >>>>> >> (fund) >> = >> >>>>> 0.45VDC >>>>> >>>>> For 500 Watts out, Rload = 81 ^ 2 / 500 = 13 ohms >>>>> >>>>> So to match to 50 ohms you need a turns ratio of SQRT(50/13) = >>>>> >> 1.9: >> >>>>> 1 so >>>>> call it 2:1 Keeping 12 turns on the secondary means you need 6 >>>>> >>> turns >>> >>>>> on >>>>> the primary >>>>> >>>>> When operating at reduced voltage, the power out will vary >>>>> > exactly > >>> as >>> >>>>> the >>>>> square of the voltage. >>>>> Recalculating from first principles for a 12V supply: >>>>> >>>>> 12V DC = 12V pk-pk = 12 / [2.SQRT(2)] * 4/pi = 5.4V RMS >>>>> >>> (fundamental) >>> >>>>> in 13 ohms should give 5.4^2/13 = 2.2 Watts >>>>> >>>>> check using ratio of voltages, squared : >>>>> >>>>> (12V/180V) ^ 2 * 500W = 2.2 Watts which is the same as above. >>>>> QED >>>>> >>>>> Your 15:12 ratio result sin a load impedance of (15/12)^2 * 50 = >>>>> >> 78 >> >>>>> ohms >>>>> >>>>> At 40V DC == 18V RMS(fund) that will give 18^2/78 = 4.1 watts >>>>> >> which >> >>> is >>> >>>>> actually LESS that you are seeing - the 2* discrepancy is odd, >>>>> > but > >>> the >>> >>>>> low >>>>> power is in the area of what you measured.. >>>>> >>>>> Andy G4JNT >>>>> >>>>> >>>>> >>>>> On 28 May 2017 at 19:34, marcocadeddu@tin.it>>>> > it> > >>>>> wrote: >>>>> >>>>> >>>>>> Hi Chris, >>>>>> >>>>>> I tried to post this message on the reflector but apparently I >>>>>> >> had >> >>> no >>> >>>>>> success.. >>>>>> As promised I keep you updated but as you can read in the >>>>>> attachment the first trials were not enocouraging... >>>>>> Andy, may I ask you to read my report? your interpretation and >>>>>> suggestion are welcome! >>>>>> >>>>>> 73, Marco IK1HSS >>>>>> >>>>>> >>>>>> -----Original message----- >>>>>> >>>>>> From: "marcocadeddu@tin.it" marcocadeddu@tin.it >>>>>> Date: Sun, 28 May 2017 17:01:33 +0200 >>>>>> To: rsgb_lf_group@blacksheep.org >>>>>> Subject: For today the FETs survived... >>>>>> >>>>>> Hi LF, >>>>>> >>>>>> hope that also the toroids of Chris survived! >>>>>> My FETs survived, but they are not working as expected :-( >>>>>> Attached the report on my attempt to duplicate the half bridge >>>>>> >> of >> >>>>>> Andy.. >>>>>> Has anyone suggestions before I try to cook all connecting to >>>>>> >> the >> >>>>>> 180Vdc supply? >>>>>> >>>>>> Thank you >>>>>> 73 Marco IK1HSS >>>>>> >>>>>> >>>>>> -- >>>>>> This message has been scanned by E.F.A. Project and is >>>>>> > believed > >> to >> >>> be >>> >>>>>> clean. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> ---------- Forwarded message ---------- >>>>>> From: "marcocadeddu@tin.it" >>>>>> To: >>>>>> Cc: >>>>>> Bcc: >>>>>> Date: Sun, 28 May 2017 17:01:33 +0200 (CEST) >>>>>> Subject: For today the FETs survived... >>>>>> Hi LF, >>>>>> >>>>>> hope that also the toroids of Chris survived! >>>>>> My FETs survived, but they are not working as expected :-( >>>>>> Attached the report on my attempt to duplicate the half bridge >>>>>> >> of >> >>>>>> Andy.. >>>>>> Has anyone suggestions before I try to cook all connecting to >>>>>> >> the >> >>>>>> 180Vdc supply? >>>>>> >>>>>> Thank you >>>>>> 73 Marco IK1HSS >>>>>> >>>>>> >>>>>> -- >>>>>> This message has been scanned by E.F.A. Project and is >>>>>> > believed > >> to >> >>> be >>> >>>>>> clean. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>> >>> >>> >> >> >> >> >> >> >> >> >> > > > > > > > > > > > > > > > > > >