Batteryless current clamps?
in [Design]
|
Prev: Tunable Bandpass Filter
Next: good book
From: Bill Sloman on 18 Nov 2009 11:50 On Nov 18, 2:46 pm, John Fields <jfie...(a)austininstruments.com> wrote: > On Wed, 18 Nov 2009 00:35:12 -0800 (PST),Bill Sloman > > > > <bill.slo...(a)ieee.org> wrote: > >On Nov 17, 3:10 pm, Jeroen Belleman <jer...(a)nospam.please> wrote: > >> Bill Slomanwrote: > >> > [...] > >> > Try to find out where the caps lock is, and unlock it. At the moment > >> > you like more like Prostheticus. > > >> > For future reference, if you don't know the answer to a question, it > >> > is not helpful to tell people that it is in some unspecified technical > >> > book somewhere. > >> > [...] > > >> You could have added a line for the OP, saying that a passive > >> current clamp is a transformer, or some such. > > >Unfortunately, I don't know that. > > --- > Finally owning up to your ignorance, huh? > --- > > >There are several ways in which a > >current clamp can work, and not all of them depend on on the clamp > >acting as a transformer. > > --- > Really? > > How about some examples, then, Mr. Bullshit Artist, and don't forget > that the keyword here is "passive". If one can rely on that "passive". Someone who knew a little more than you might extract some of the power circulating through the wire and produce an active solution without an external power source. -- Bill Sloman, Nijmegen
From: Fester Bestertester on 18 Nov 2009 12:08 > On Tue, 17 Nov 2009 00:18:55 -0800, Fester Bestertester <fbt(a)fbt.net> > wrote: > >> I'm curious how the Fluke i200s current clamp probe can give mV output >> without the use of batteries. >> >> How is this done? If one is measuring 200A I can see how the magnetic field >> could generate enough current in the probe to support some high-impedance, >> low-draw circuitry. >> >> But when measuring on the low scale, say, 2 or 3 amps, how could the probe >> output a few hundred mV? (The clamp is spec'd to output 100mV / amp on the >> 20A low scale, 10mV on the 200A high scale.) >> >> Can someone explain this to me? I'm fascinated to see it's possible & >> curious >> to know how. > > --- > OK. > > A passive clamp-on ammeter is essentially the secondary of a transformer > wound on a core that can be opened or closed in order to get it around a > conductor so the current in that conductor can be measured without > cutting it and using a conventional ammeter. > [...] > JF FINALLY an answer on-topic. Thank you. After watching the 3 Stooges act that is aee / sed... Sheesh! I AM FBt
From: Pointless Posts on 18 Nov 2009 13:57 Fester Bestertester wrote: >> On Tue, 17 Nov 2009 00:18:55 -0800, Fester Bestertester >> <fbt(a)fbt.net> >> wrote: >> >>> I'm curious how the Fluke i200s current clamp probe can give >>> mV >>> output without the use of batteries. >>> >>> How is this done? If one is measuring 200A I can see how the >>> magnetic field could generate enough current in the probe to >>> support some high-impedance, low-draw circuitry. >>> >>> But when measuring on the low scale, say, 2 or 3 amps, how >>> could >>> the probe output a few hundred mV? (The clamp is spec'd to >>> output >>> 100mV / amp on the 20A low scale, 10mV on the 200A high >>> scale.) >>> >>> Can someone explain this to me? I'm fascinated to see it's >>> possible >>> & curious >>> to know how. >> >> --- >> OK. >> >> A passive clamp-on ammeter is essentially the secondary of a >> transformer wound on a core that can be opened or closed in >> order to >> get it around a conductor so the current in that conductor can >> be >> measured without cutting it and using a conventional ammeter. >> [...] >> JF > > FINALLY an answer on-topic. Thank you. > > After watching the 3 Stooges act that is aee / sed... > > Sheesh! > > I AM FBt Admitted that the S/N ratio on Usenet can be frustrating. But did you stop to consider the possibility that a) you failed to grasp other attempts to explain it to you; b) your question was so elementary for *this* group that few people bothered; c) your last post might be taken as a slap in the face by those who tried to help.
From: John Fields on 18 Nov 2009 15:36 On Wed, 18 Nov 2009 08:50:08 -0800 (PST), Bill Sloman <bill.sloman(a)ieee.org> wrote: >On Nov 18, 2:46�pm, John Fields <jfie...(a)austininstruments.com> wrote: >> On Wed, 18 Nov 2009 00:35:12 -0800 (PST),Bill Sloman >> <bill.slo...(a)ieee.org> wrote: >> >There are several ways in which a >> >current clamp can work, and not all of them depend on on the clamp >> >acting as a transformer. >> >> --- >> Really? >> >> How about some examples, then, Mr. Bullshit Artist, and don't forget >> that the keyword here is "passive". > >If one can rely on that "passive". --- Can't come up with anything, huh? What a surprise!!! --- >Someone who knew a little more than >you might extract some of the power circulating through the wire and >produce an active solution without an external power source. --- I guess that'll keep you out of the running, n'est-ce pas? JF
From: Fester Bestertester on 18 Nov 2009 16:54
> Admitted that the S/N ratio on Usenet can be frustrating. But did > you stop to consider the possibility that a) you failed to grasp > other attempts to explain it to you; b) your question was so > elementary for *this* group that few people bothered; c) your > last post might be taken as a slap in the face by those who tried > to help. Right you are. A big thank you to those responders who gave answers to my question. Much appreciated. My comment was addressed to the "noise". :-) FBt |