Hello,
just to give a short update..
The working week elapsed quite quickly so today I was again checking..
First the guard circuit after the tank coil is now fixed with no risk
of hotmelt glue melted :-D
The tank coil now has 86T and I started with a 18T link coil: it was
too efficient cutting power so turn after turn I decreased the link:
finally with 9T I had a satisfactory behaviour :-) just a small
reduction of power in comparison to the amplifier without guard
circuit, about 2dB of power reduction on 25 ohms load and 6dB power
reduction on short circuited load (under mismatching condition
reduction of the supply current and evidence of recirculating current
from the guard circuit).
So it was time to fly.. leaving the 50V PS and going up..
With an insulation supply transformer I started to increase the Vac but
approaching 100Vdc to the PA, the switching transistor of the PS
(an2SC5386 rated at 1500V 8A) failed and I had for a while 300 Vdc..
I heard a cracking noise and of course stopped all so had no time to
see the power out.
The FETs are safe :-))) but the 6x1000pF caps in the tank circuit are
cooked..
So now I have some work again to do ;-)
Will rewire the PS for direct rectification of the mains, replacing the
tank capacitors with a serie/parallel combination and a new output
transformer (this one was ok for 180Vdc but is a bit under stress if
the suplly goes to 340Vdc).
That's all for the moment.
Long life to the FETs :-))
Marco, IK1HSS
in the mean while the wspr beacon is still transmitting at qrp level
originating limit signals.. almost all nights I have reports from
OH2EAT for short time (about 1 hour in the middle of the night) :-)
thank you Tatu for being there!
----Messaggio originale----
Da: [email protected]
Data: 5-giu-2017 15.51
A: <[email protected]>
Ogg: R: Re: R: Re: R: Re: LF: Re: I: Fw: For today the FETs survived...
Hi Stefan,
and thank you for effort and suggestion :-)
Indeed carefully checking while testing I found what was going wrong
beyond 30Vdd of supply to FETs: the xfmr between the IXDD stage and
gates became very hot!!
Nothing up to 30Vdd but then.. xfmr warm and degradated wave forms!
The xfmr was wound on a little binocular form made of N30 material and
I replaced it with a BN43-202 increasing the number of turns (total
inductance a bit more than 1mH) and everything was solved and PA now
is
almost ready to go to the final intended supply of 180Vdc.
The tank coil, made of 1,5mm² wire was then warming, and yesterday I
made a new, bulky, coil with 2,5 mm² which also get warm (abt 60°C)
melting the hot melt glue used to fix to the chassis... so now some
mechanical artwork for new support without hotmelt glue...
Marco IK1HSS
----Messaggio originale----
Da: [email protected]
Data: 5-giu-2017 11.18
A: <[email protected]>
Ogg: Re: R: Re: R: Re: LF: Re: I: Fw: For today the FETs survived...
Hello Marco,
I was unable to write a longer text for a few days (no desktop PC
available, just the smartphone and Teamviewer) so my answer is a bit
late. You've got a lot of advice since that time.
I'm just adding what came to my mind...
-I assume you already checked that the supply voltages stay constand
in
any working point.
-The gate voltages are important. Also the duty cycle should be
constant
and close to 50% for best operation.
In my H bridge PA for 137 kHz the gate voltage is +- 8V, quite a
rectangular waveform. Unfortunately i have no scope captures quickly
available.
-Try to lower the 4 Ohm resistor after the IDXX driver. It is there to
avoid oscillations after the switching slopes. Maybe 2 Ohm is enough.
-Even more important: Make sure the transformer is wound for a minimum
stray inductance because this will quickly lead to strong
oscillations.
Wind all the 3 windings equally spread arround the whole core
(ferrite,
e.g. N30, AL>2000nH). Wind them trifilar, not separated.
If there are still problems show us images of: The gate source
voltage,
the gate drive transformer.
73, Stefan
Am 03.06.2017 16:44, schrieb [email protected]:
> Hi Stefan,
>
> and thank you :-) so you have too something to mumble while sending
> VLF SMS ;-)
> There is nothing really new.. I started from an avalable
> chassis with on board a PS giving 180Vdc (1200W) and assembled the
> Andy's half bridge 700W switching PA and before give it the full
power
> I'm checking with lower DC supply. Attached you see the schematic
with
> some change at the moment..
> The output xfmr has 7T/19T, the coil of the guard circuit is not
> connected (now is in serie with L2) and the resonating caps now are
> 5x1000pF in parallel.
> The aim is finally with 180Vdc of supply have an output of 0,5÷1kW
> but.... as you probably red in the previous messages, from 10 to
30Vdc
> the PA runs, at low power of course (up to 15W), and complies the
> calculations; with supply between 30 and 50 Vdc the output go down
to
a
> couple of W.
> I made several trials it the last days, changing the core of the
xfmr,
> the turn ratio, the kind of capacitators but nothing changes (or at
> least the change are within a fraction of dB).
>
> that's the sad history Stefan...
> All thoughts and suggestions are welcome! (including go to fish ;-))
)
> Marco
>
> ----Messaggio originale----
> Da: [email protected]
> Data: 3-giu-2017 16.19
> A:<[email protected]>
> Ogg: Re: R: Re: LF: Re: I: Fw: For today the FETs survived...
>
> 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 [email protected]:
>
>> 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: [email protected]
>> Data: 2-giu-2017 15.58
>> A:<[email protected]>
>> 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:<[email protected]>
>> To:<[email protected]>
>> 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: [email protected]
>> Data: 2-giu-2017 14.36
>> A:<[email protected]>
>> 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:<[email protected]>
>> To:<[email protected]>
>> 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: [email protected]
>> Data: 1-giu-2017 22.20
>> A:<[email protected]>
>> 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: [email protected]
>> Data: 1-giu-2017 22.03
>> A:<[email protected]>
>> 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, [email protected]<[email protected]>
>> 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: [email protected]
>>> Data: 31-mag-2017 21.05
>>> A:<[email protected]>
>>> 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: [email protected]
>>> Data: 31-mag-2017 20.39
>>> A:<[email protected]>
>>> Cc:<[email protected]>
>>> 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, [email protected]<[email protected]>
>>> 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: [email protected]
>>>> Data: 30-mag-2017 23.50
>>>> A:<[email protected]>
>>>> Cc:<[email protected]>
>>>> 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<[email protected]>
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, [email protected]<marcocadeddu@tin.
>>>>>
>>>>>
>> 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: [email protected]
>>>>>> Data: 28-mag-2017 21.18
>>>>>> A: "[email protected]"<[email protected]>,
>>>>>> <[email protected]>
>>>>>> Cc:<[email protected]>
>>>>>> 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, [email protected]<marcocadeddu@tin.
>>>>>>
>>>>>>
>> 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: "[email protected]" [email protected]
>>>>>>> Date: Sun, 28 May 2017 17:01:33 +0200
>>>>>>> To: [email protected]
>>>>>>> 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: "[email protected]"<[email protected]>
>>>>>>> To:<[email protected]>
>>>>>>> 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.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
|
