(OT) Grounding Mat
Locked
12
12
 
|
I'm sure this question has been answered before, if someone could point me
in the right direction, I would appreciate it. PC and K2 not talking. K2 Port ON; Computer-4800 baud, 8 data bits, no parity, 2 stop bits. Cable connections look good, RTS/CTS Loopback not used. Trying to use this setup with N1MM Logger. I can see the transceiver frequency in the software and it does respond to frequency changes and band changes, but thats all. Do I now check the voltages on the KIO2, or is there another place to look first? 73 Lou, KD2MU ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
Apparently it IS talking as you see the frequency reflected in the MM
display. The K2 is receiving a command to display the frequency, therefore it works TO the K2. That you see the frequency in MM means that the answer to the poll is being properly formatted and sent FROM the K2. Can you be more specific as to what is NOT happening? 73, Guy. On Thu, Mar 25, 2010 at 5:05 PM, Louis Visconti <[hidden email]> wrote: > I'm sure this question has been answered before, if someone could point me > in the right direction, I would appreciate it. > PC and K2 not talking. K2 Port ON; Computer-4800 baud, 8 data bits, no > parity, 2 stop bits. Cable connections look good, RTS/CTS Loopback not used. > Trying to use this setup with N1MM Logger. I can see the transceiver > frequency in the software and it does respond to frequency changes and band > changes, but thats all. Do I now check the voltages on the KIO2, or is there > another place to look first? > > 73 > Lou, KD2MU > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Louis Visconti
Lou,
If you can communicate in any way with the K2 (and you *can* because you said the frequency is displayed in N1MM), then the KIO2 is enirely capable of communications. Look at the software application setup for the problem. You might try putting the RTS/CTS jumper on the connector at the computer end. Even if your application does not use it, the jumper will do no harm 73, Don W3FPR Louis Visconti wrote: > I'm sure this question has been answered before, if someone could point me > in the right direction, I would appreciate it. > PC and K2 not talking. K2 Port ON; Computer-4800 baud, 8 data bits, no > parity, 2 stop bits. Cable connections look good, RTS/CTS Loopback not used. > Trying to use this setup with N1MM Logger. I can see the transceiver > frequency in the software and it does respond to frequency changes and band > changes, but thats all. Do I now check the voltages on the KIO2, or is there > another place to look first? > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Gary Hvizdak
Gary Hvizdak wrote:
> Wed Mar 24 22:14:20 EDT 2010 LS (W5QD) wrote ... > > The mat doesn't have to be grounded ... > > > WARNING! The statement W5QD just posted is completely false! The ESD mat > must be grounded in order for it to be able to dissipate an electrical The full reply from W5QD was perfectly correct. Everything conductive has to be connected together, but there is no need to connect to the earth itself. In practice, if the soldering station is mains powered, the result will be that it is also connected to the green wire in the mains, although that can be at a significantly different potential than the local true earth. In fact, unless there is a high resistance in the lead to the mat, it can be very dangerous to connect it to true earth, as it is usually possible to touch the connection to the mat and something cannected to the green wire, at the same time. > charge. If you don't ground the mat, then you might as well not have it, > since your entire work area could very easily be floating at tens of > thousands of volts above ground, just waiting for "somewhere" to discharge > "to" and "something" to discharge "through"! That is perfectly acceptable, as long as there is no way of touching something that has a relatively low resistance to true earth. (Incidentally, I have a feeling that true earth isn't actually electrically neutral, something has to balance the charge in thunderclouds. In a practical amateur environment, the optimum ground for this purpose is the green wire, and bringing any other ground into the situation can be dangerous. However, if you have a battery or gas soldering iron, and no conductors which could touch the work, but aren't connected to the mat, there need be no connection at all to anything approximating true earth. The green wire is not a best approximation to true earth for this purpose, it is actually the ideal thing to connect to, even if it bears no resemblance to true earth. -- David Woolley "we do not overly restrict the subject matter on the list, and we encourage postings on a wide range of amateur radio related topics" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Edward R Cole
On Thu, 25 Mar 2010 10:03:42 -0800, Edward Cole wrote:
>For some test equipment, isolation transformers should be used >because they ground circuits that you may not want grounded. Aside from the fractured logic in this sentence, power isolation transformers, installed per NEC, do NOT isolate the green wire on one side from the green wire on the other, because code requires that ALL grounds (including all green wires, and the chassis of all equipment) be bonded together! NEC also requires that the neutral of every transformer secondary must be bonded to ground, and as noted above, all grounds must be bonded together. So the question is, what, exactly, from a grounding perspective, do you expect to gain by using an isolation transformer? What the isolation transformer CAN do, IF it has one or more Faraday shields, and IF they are properly terminated, is reduce the transfer of noise between line and neutral from one winding to the other. Without those Faraday shields, the capacitance between windings will still couple most of the noise. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by n7ws
On Thu, 25 Mar 2010 08:23:52 -0700 (PDT), Wes Stewart wrote:
>Also known as the, "You can't get a static charge on a wet cat" theory. > One thing is certain: you will have a devil of a time assembling a K3 with a wet cat tied to your wrist. 73, Drew AF2Z ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Jim Brown-10
I find this (that there must always be ground continuity across and
isolation transformer, and that one end of the secondary must be connected to neutral) unlikely. There are at least five circumstances in which this doesn't apply under UK regulations, and I am pretty sure that the same situations apply in the USA. The first is Separated Extra Low Voltage (SELV - e.g. the common or garden wall wart). The second is the common or garden bathroom shaver socket. The third, is class IT systems, which have no earth at all, and are required in certain areas of hospitals. The fourth is special non-conducting environments, where it is physically impossible to touch more than one conductor at a time. And the fifth is environments where all exposed conductors are bonded together, but not to the supply earth. The last two are specialist cases. Jim Brown wrote: > Aside from the fractured logic in this sentence, power isolation > transformers, installed per NEC, do NOT isolate the green wire on one side > from the green wire on the other, because code requires that ALL grounds > (including all green wires, and the chassis of all equipment) be bonded > together! > > NEC also requires that the neutral of every transformer secondary must be > bonded to ground, and as noted above, all grounds must be bonded together. > So the question is, what, exactly, from a grounding perspective, do you > expect to gain by using an isolation transformer? > David Woolley "we do not overly restrict the subject matter on the list, and we encourage postings on a wide range of amateur radio related topics" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
Dave,
An isolation transformer *does* isolate the neutral (and the hot), but does *not* isolate the "green wire ground" - and for safety, it should not. 73, Don W3FPR David Woolley (E.L) wrote: > I find this (that there must always be ground continuity across and > isolation transformer, and that one end of the secondary must be > connected to neutral) unlikely. There are at least five circumstances > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by David Woolley (E.L)
On Sat, 27 Mar 2010 10:20:09 +0000, David Woolley (E.L) wrote:
>I find this (that there must always be ground continuity across and >isolation transformer, and that one end of the secondary must be >connected to neutral) unlikely. There are at least five circumstances >in which this doesn't apply under UK regulations, and I am pretty sure >that the same situations apply in the USA. I can't speak to UK regulations, but I am certain about those in North America. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Don Wilhelm-4
On Sat, 27 Mar 2010 09:32:12 -0400, Don Wilhelm wrote:
>An isolation transformer *does* isolate the neutral (and the hot), NO! This is a summary of NEC (National Electric Code) requirements: The NEUTRAL of a transformer on the secondary side MUST be bonded to the equipment ground (steel conduit, the green wire, building structure, etc), and that green wire must be carried from the breaker panel to each outlet and to the transformer. The neutral conductor that feeds the primary side of the transformer must be bonded to ground at the service for the building (that is, the main breaker panel). And, as we all know, all groundes must be bonded together. Thus, an isolation transformer does NOT isolate either the neutral or the equipment ground. What an isolation transformer DOES do is reduce the voltage between neutral and ground to zero. It also shortens the return path for leakage currents on the green wire -- they now return to that transformer, not to the more distant breaker panel at the service entrance. This has the potential to reduce noise current on the shield of signal cables. BUT -- the simple bonding regimen outlined in my Ham Interfacing Power Point is a MUCH less expensive AND more effective solution. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
> NO! This is a summary of NEC (National Electric Code)
> requirements: The > NEUTRAL of a transformer on the secondary side MUST be > bonded to the > equipment ground (steel conduit, the green wire, building > structure, etc), > and that green wire must be carried from the breaker panel > to each outlet and > to the transformer. The neutral conductor that feeds the > primary side of the > transformer must be bonded to ground at the service for > the building (that > is, the main breaker panel). And, as we all know, all > groundes must be bonded > together. Thus, an isolation transformer does NOT isolate > either the neutral > or the equipment ground. I wonder when that changed? All of my isolation transformers, probably manufactured in the 70's or 80's, float the mains terminals on the load side. We used them all the time working on AC/DC radios and I still use them now working on SMPS. Only the case and safety grounds are grounded. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Jim Brown-10
But Jim,
The secondary of an isolation transformer is fully isolated - i.e. floating AC. The fact that the neutral of the transformer input side is bonded to the green wire ground is quite a different thing. A proper isolation transformer has no relationship to neutral on the secondary side - only the safety ground and the voltage across the secondary winding. Remember the old AC/DC receivers that had one side of the AC line tied to the chassis! Every proper service bench had an isolation transformer during that era. 73, Don W3FPR Jim Brown wrote: > On Sat, 27 Mar 2010 09:32:12 -0400, Don Wilhelm wrote: > > >> An isolation transformer *does* isolate the neutral (and the hot), >> > > NO! This is a summary of NEC (National Electric Code) requirements: The > NEUTRAL of a transformer on the secondary side MUST be bonded to the > equipment ground (steel conduit, the green wire, building structure, etc), > and that green wire must be carried from the breaker panel to each outlet and > to the transformer. The neutral conductor that feeds the primary side of the > transformer must be bonded to ground at the service for the building (that > is, the main breaker panel). And, as we all know, all groundes must be bonded > together. Thus, an isolation transformer does NOT isolate either the neutral > or the equipment ground. > > What an isolation transformer DOES do is reduce the voltage between neutral > and ground to zero. It also shortens the return path for leakage currents on > the green wire -- they now return to that transformer, not to the more > distant breaker panel at the service entrance. This has the potential to > reduce noise current on the shield of signal cables. BUT -- the simple > bonding regimen outlined in my Ham Interfacing Power Point is a MUCH less > expensive AND more effective solution. > > 73, > > Jim Brown K9YC > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: (OT) Isolation Transfomer Bonding
|
|
This is one of those areas where the term "isolation transformer" can take
on a different meaning and conform to a different set of compliance standards, depending on whether it's located before or after a receptacle. UL 1950 appears to allow for full isolation of the neutral on the isolation transformer's secondary where the iso-transformer is used after a receptacle. By contrast, isolation transformers used on feeder or branch circuits on the "NEC side" of power distribution require that neutral and ground be bonded at the transformer secondary. This is known as a "separately-derived power source." When such source is created by the iso-transformer, this is the only other instance allowed by the NEC where neutral and ground are bonded beyond the Xo ground at the service entrance panel. The IEEE Emerald Book repeatedly discusses a reduction in common-mode noise when the secondary's neutral and ground are bonded. This is my take after reading applicable portions of the NEC, UL 1950 and IEEE Emerald Book (2005 Sec. 9.9.5 and 10.4.2.1). I'll concede that my thoughts on this may not be correct. Paul, W9AC ----- Original Message ----- From: "Don Wilhelm" <[hidden email]> To: "Jim Brown" <[hidden email]> Cc: "Elecraft List" <[hidden email]> Sent: Saturday, March 27, 2010 4:23 PM Subject: Re: [Elecraft] (OT) Grounding Mat > But Jim, > > The secondary of an isolation transformer is fully isolated - i.e. > floating AC. The fact that the neutral of the transformer input side is > bonded to the green wire ground is quite a different thing. A proper > isolation transformer has no relationship to neutral on the secondary > side - only the safety ground and the voltage across the secondary > winding. > > Remember the old AC/DC receivers that had one side of the AC line tied > to the chassis! Every proper service bench had an isolation transformer > during that era. > > 73, > Don W3FPR > > Jim Brown wrote: >> On Sat, 27 Mar 2010 09:32:12 -0400, Don Wilhelm wrote: >> >> >>> An isolation transformer *does* isolate the neutral (and the hot), >>> >> >> NO! This is a summary of NEC (National Electric Code) requirements: The >> NEUTRAL of a transformer on the secondary side MUST be bonded to the >> equipment ground (steel conduit, the green wire, building structure, >> etc), >> and that green wire must be carried from the breaker panel to each outlet >> and >> to the transformer. The neutral conductor that feeds the primary side of >> the >> transformer must be bonded to ground at the service for the building >> (that >> is, the main breaker panel). And, as we all know, all groundes must be >> bonded >> together. Thus, an isolation transformer does NOT isolate either the >> neutral >> or the equipment ground. >> >> What an isolation transformer DOES do is reduce the voltage between >> neutral >> and ground to zero. It also shortens the return path for leakage currents >> on >> the green wire -- they now return to that transformer, not to the more >> distant breaker panel at the service entrance. This has the potential to >> reduce noise current on the shield of signal cables. BUT -- the simple >> bonding regimen outlined in my Ham Interfacing Power Point is a MUCH less >> expensive AND more effective solution. >> >> 73, >> >> Jim Brown K9YC >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by W8JI
On Sat, 27 Mar 2010 16:09:36 -0400, Tom W8JI wrote:
>> NO! This is a summary of NEC (National Electric Code) >> requirements: The >> NEUTRAL of a transformer on the secondary side MUST be >> bonded to the >> equipment ground (steel conduit, the green wire, building >> structure, etc), >> and that green wire must be carried from the breaker panel >> to each outlet and >> to the transformer. The neutral conductor that feeds the >> primary side of the >> transformer must be bonded to ground at the service for >> the building (that >> is, the main breaker panel). And, as we all know, all >> groundes must be bonded >> together. Thus, an isolation transformer does NOT isolate >> either the neutral >> or the equipment ground. >I wonder when that changed? All of my isolation >transformers, probably manufactured in the 70's or 80's, >float the mains terminals on the load side. We used them all >the time working on AC/DC radios and I still use them now >working on SMPS. Only the case and safety grounds are >grounded. I have some UTC or Triads like that too. You can probably get away with using them on a service bench, but an electrical inspector would red tag you if you tried to install them without bonding the neutral. If I'm not mistaken, there also needs to be a breaker or fuse somewhere. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
«
Return to [K3]
|
1 view|%1 views
| Free forum by Nabble | Edit this page |