OPTOISOLATED DC-DC
in [Design]
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From: Sjouke Burry on 29 Apr 2010 19:55 Jan Panteltje wrote: > On a sunny day (Thu, 29 Apr 2010 13:27:16 -0700) it happened John Larkin > <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in > <dqqjt5tded693q7b3oifcq9hm92volte6e(a)4ax.com>: > >> On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> hamilton wrote: >>>> On 4/29/2010 12:09 PM, Joerg wrote: >>>>> Spehro Pefhany wrote: >>>>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>>>> >>>>>>> Gentlemen, I was curious on any ideas of an opto dc-dc converter >>>>>>> providing 20mA. Small footprint and heighth.. >>>>>>> Any ideas? Please and Thank You. >>>>>>> >>>>>>> VIN-8-16VDC >>>>>>> VOUT 5VDC 20mA, >>>>>> It's certainly possible (since you don't specify efficiency), but it >>>>>> probably would cost in the thousands of dollars. JDS Uniphase might be >>>>>> a place to start. It could well be a practical solution for such >>>>>> challenging problems as powering instrumentation that's at 100's of kV >>>>>> potential relative to ground. >>>>> Even that I'd try to power magnetically through some porcelain or glass >>>>> insulation. >>>>> >>>> That's not opto isolation, its magnetic, right ?? >>>> >>> Yes, just meant as a hint that you can do this stuff at high isolation >>> voltages. >>> >>> >>>> So the OPs request is not feasible. >>>> >>> Maybe feasible but it gets expensive. >>> >>>> hamilton >>>> >>>> PS: OK, solar cells maybe. >>> >>> With small footprint and height that can become a challenge. >> >> Motor. Long fiberglass rod. Generator. Megavolts of isolation. >> >> John > > Well, been thinking: > Motor, belt, generator. > It is not optical, but OK, if the belt is isolating you get a very good efficiency :-) An isolating belt is how they make a de Graaf generator, to produce high voltage. It would produce a very nasty leak to ground. a plastic rod with motor/dynamo attached would be better.
From: Joerg on 29 Apr 2010 20:17 John Larkin wrote: > On Thu, 29 Apr 2010 13:33:03 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> John Larkin wrote: >>> On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> hamilton wrote: >>>>> On 4/29/2010 12:09 PM, Joerg wrote: >>>>>> Spehro Pefhany wrote: >>>>>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>>>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>>>>> >>>>>>>> Gentlemen, I was curious on any ideas of an opto dc-dc converter >>>>>>>> providing 20mA. Small footprint and heighth.. >>>>>>>> Any ideas? Please and Thank You. >>>>>>>> >>>>>>>> VIN-8-16VDC >>>>>>>> VOUT 5VDC 20mA, >>>>>>> It's certainly possible (since you don't specify efficiency), but it >>>>>>> probably would cost in the thousands of dollars. JDS Uniphase might be >>>>>>> a place to start. It could well be a practical solution for such >>>>>>> challenging problems as powering instrumentation that's at 100's of kV >>>>>>> potential relative to ground. >>>>>> Even that I'd try to power magnetically through some porcelain or glass >>>>>> insulation. >>>>>> >>>>> That's not opto isolation, its magnetic, right ?? >>>>> >>>> Yes, just meant as a hint that you can do this stuff at high isolation >>>> voltages. >>>> >>>> >>>>> So the OPs request is not feasible. >>>>> >>>> Maybe feasible but it gets expensive. >>>> >>>>> hamilton >>>>> >>>>> PS: OK, solar cells maybe. >>>> With small footprint and height that can become a challenge. >>> >>> Motor. Long fiberglass rod. Generator. Megavolts of isolation. >>> >> ... minor imbalance, some rumbling is heard, bigger imbalance, snapping >> noise, stuff flying about, hissing, amperage stench develops, siren >> begins to wail, the captain from engine company 89 hollers something, >> his guys hurriedly don their helmets ... >> >> :-) > > You would enjoy that, wouldn't you? > No joke, I have personally seen an aircraft go down because of it. New design, prototype was ready to go. Engine up front, prop in the rear, long shaft going through the fiber fuselage. I did some EMI fixing because that arrangement was causing static in the NAV/COM and this was a bear to debug because there was no ground to speak of. But I got it quiet. Then I wondered aloud whether the long shaft in a somewhat compliant fiber fuselage would not get out of whack at some rpm. "Nah, it was always fine in the run-ups and vibration tests" ... "What if there's g-load on the frame, like in a turn?" ... "Nah, it'll be fine". Test pilot donned his leather helmet, fired her up. At first it all sounded ok but then somehow the rpms dropped during the takeoff roll and the engine sounded very labored. From then on the flight was doomed. Due to the proximity of the fence the pilot had no choice but to continue the take-off. It all ended in a potato field half a mile away and luckily the pilot was fine. The aircraft did not fare so well, suffered a serious prop strike which I guess meant a mandatory engine teardown. Later I inquired as to what went wrong. "Strong vibrations" ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Spehro Pefhany on 29 Apr 2010 20:21 On Thu, 29 Apr 2010 23:25:12 GMT, the renowned Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Thu, 29 Apr 2010 13:27:16 -0700) it happened John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in ><dqqjt5tded693q7b3oifcq9hm92volte6e(a)4ax.com>: > >>On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> >>wrote: >> >>>hamilton wrote: >>>> On 4/29/2010 12:09 PM, Joerg wrote: >>>>> Spehro Pefhany wrote: >>>>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>>>> >>>>>>> Gentlemen, I was curious on any ideas of an opto dc-dc converter >>>>>>> providing 20mA. Small footprint and heighth.. >>>>>>> Any ideas? Please and Thank You. >>>>>>> >>>>>>> VIN-8-16VDC >>>>>>> VOUT 5VDC 20mA, >>>>>> >>>>>> It's certainly possible (since you don't specify efficiency), but it >>>>>> probably would cost in the thousands of dollars. JDS Uniphase might be >>>>>> a place to start. It could well be a practical solution for such >>>>>> challenging problems as powering instrumentation that's at 100's of kV >>>>>> potential relative to ground. >>>>> >>>>> Even that I'd try to power magnetically through some porcelain or glass >>>>> insulation. >>>>> >>>> That's not opto isolation, its magnetic, right ?? >>>> >>> >>>Yes, just meant as a hint that you can do this stuff at high isolation >>>voltages. >>> >>> >>>> So the OPs request is not feasible. >>>> >>> >>>Maybe feasible but it gets expensive. >>> >>>> hamilton >>>> >>>> PS: OK, solar cells maybe. >>> >>> >>>With small footprint and height that can become a challenge. >> >> >>Motor. Long fiberglass rod. Generator. Megavolts of isolation. >> >>John > >Well, been thinking: >Motor, belt, generator. >It is not optical, but OK, if the belt is isolating you get a very good efficiency :-) Just spray some charge on the belt and you might not need the generator. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: Phil Allison on 29 Apr 2010 21:59 "John Larkin" "Phil Allison" > >>"Johnny5" <dirtylogicdesigns(a)gmail.com >> >> >>** Google Monkey alert !! >> >> >>> Gentlemen, I was curious on any ideas of an opto dc-dc converter >>> providing 20mA. Small footprint and heighth.. >>> Any ideas? Please and Thank You. >>> >>> VIN-8-16VDC >>> VOUT 5VDC 20mA, >> >> >>** Ever though of using solar cells and a 12 volt lamp ?? >> > > Done carefully, that might approach 1% efficiency. ** Much more than that with a high efficiency LED lamp. Hardly matters when you are only generating 100mW. ..... Phil
From: John Larkin on 29 Apr 2010 23:22
On Thu, 29 Apr 2010 17:17:53 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Thu, 29 Apr 2010 13:33:03 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> John Larkin wrote: >>>> On Thu, 29 Apr 2010 11:58:40 -0700, Joerg <invalid(a)invalid.invalid> >>>> wrote: >>>> >>>>> hamilton wrote: >>>>>> On 4/29/2010 12:09 PM, Joerg wrote: >>>>>>> Spehro Pefhany wrote: >>>>>>>> On Thu, 29 Apr 2010 07:37:08 -0700 (PDT), Johnny5 >>>>>>>> <dirtylogicdesigns(a)gmail.com> wrote: >>>>>>>> >>>>>>>>> Gentlemen, I was curious on any ideas of an opto dc-dc converter >>>>>>>>> providing 20mA. Small footprint and heighth.. >>>>>>>>> Any ideas? Please and Thank You. >>>>>>>>> >>>>>>>>> VIN-8-16VDC >>>>>>>>> VOUT 5VDC 20mA, >>>>>>>> It's certainly possible (since you don't specify efficiency), but it >>>>>>>> probably would cost in the thousands of dollars. JDS Uniphase might be >>>>>>>> a place to start. It could well be a practical solution for such >>>>>>>> challenging problems as powering instrumentation that's at 100's of kV >>>>>>>> potential relative to ground. >>>>>>> Even that I'd try to power magnetically through some porcelain or glass >>>>>>> insulation. >>>>>>> >>>>>> That's not opto isolation, its magnetic, right ?? >>>>>> >>>>> Yes, just meant as a hint that you can do this stuff at high isolation >>>>> voltages. >>>>> >>>>> >>>>>> So the OPs request is not feasible. >>>>>> >>>>> Maybe feasible but it gets expensive. >>>>> >>>>>> hamilton >>>>>> >>>>>> PS: OK, solar cells maybe. >>>>> With small footprint and height that can become a challenge. >>>> >>>> Motor. Long fiberglass rod. Generator. Megavolts of isolation. >>>> >>> ... minor imbalance, some rumbling is heard, bigger imbalance, snapping >>> noise, stuff flying about, hissing, amperage stench develops, siren >>> begins to wail, the captain from engine company 89 hollers something, >>> his guys hurriedly don their helmets ... >>> >>> :-) >> >> You would enjoy that, wouldn't you? >> > >No joke, I have personally seen an aircraft go down because of it. New >design, prototype was ready to go. Engine up front, prop in the rear, >long shaft going through the fiber fuselage. I did some EMI fixing >because that arrangement was causing static in the NAV/COM and this was >a bear to debug because there was no ground to speak of. But I got it >quiet. Then I wondered aloud whether the long shaft in a somewhat >compliant fiber fuselage would not get out of whack at some rpm. "Nah, >it was always fine in the run-ups and vibration tests" ... "What if >there's g-load on the frame, like in a turn?" ... "Nah, it'll be fine". > >Test pilot donned his leather helmet, fired her up. At first it all >sounded ok but then somehow the rpms dropped during the takeoff roll and >the engine sounded very labored. From then on the flight was doomed. Due >to the proximity of the fence the pilot had no choice but to continue >the take-off. It all ended in a potato field half a mile away and >luckily the pilot was fine. The aircraft did not fare so well, suffered >a serious prop strike which I guess meant a mandatory engine teardown. >Later I inquired as to what went wrong. "Strong vibrations" ... The drive shaft on the F35 JSF transmits 32,000 horsepower to the forward lift fan. I understand there was some concern about stability. In fact, we sold some waveform generators to help out with the simulation. I think it's a tube, not a solid rod. John |