just call it 2 phase

On Fri, 27 Mar 2009 15:42:42 -0400 Michael A. Terrell wrote: | | snipped-for-privacy@ipal.net wrote: |> |> On Wed, 25 Mar 2009 07:57:52 -0400 Michael A. Terrell wrote: |> |> | A lot of transformerless tube radios were sold as AC/DC, and wouldn't |> | have worked if it was a Phil claims. You just had to make sure the |> | power plug was inserted the right way, or you got no B+ for the tubes. |> |> And these were plugged into Edison's DC system? | | | No. They were plugged into the cigarette lighter of the flying | saucers at Area 51. If you are going to continue to post nonsense, I | might as well, too. :(

I asked a question. Obviously you never provide useful answers.

Projecting your failings again, or just another pathetic attempt at trolling?

Sure, from line frequency up to 11 GHZ. Ever work with Sallen-Key? Butterworth? How about FIR filters, and using them with DSP? How about UHF diplexers that handle over 200 KW? A filter can only do so much with the input, or we would still be using TRF radios. IOW, you can't make a silk purse out of a sow's ear, no matter how much you whine, or how many hissy fits you throw.

The only 'filter' that would work with your ridiculous pulsing DC would be a battery bank or a band of huge electrolytics. The battery would be a better choice, because the electrolytics would heat up quite a bit from all the AC flowing through them.

Those arching brushes would fail every EMI/RFI standard. Do you understand that? Or to make it even simpler for you, it would wipe out all radio & TV OTA signals for quite a distance. If it was a large power plant, it could be a mile or more each side of the HV distribution lines.

You never post any useful questions. You just post crap, or try to play troll, but you aren't capable of even doing that properly. WTH would they have built AC/DC radios if they couldn't be operated on Edison's DC generator designs? You can't be that stupid? Or can you?

On Sun, 29 Mar 2009 03:57:55 -0400 Michael A. Terrell wrote: | | snipped-for-privacy@ipal.net wrote: |> |> On Fri, 27 Mar 2009 15:34:59 -0400 Michael A. Terrell wrote: |> | |> | snipped-for-privacy@ipal.net wrote: |> |>

|> |> On Wed, 25 Mar 2009 21:44:03 -0400 Michael A. Terrell wrote: |> |>

|> |> | If homes were still fed with DC, the generators would have to be a |> |> | couple miles from your home. Also, it doesn't have to pulse to charge a |> |> | battery. |> |>

|> |> If using Edison's 220/110VDC split system, even a couple miles would be way |> |> too far. Today would could do transmission, distribution, service, and |> |> utilization, and different DC voltages and keep it DC all the way. It would |> |> still not be as cheap as AC, but it is possible to do. |> | |> | |> | Yawn. You could post something that makes sense, but you rarely do. |> | Lots of stupid things can be done, but why, other than to prove |> | someone's ignorance? |> |> So you don't really understand electricity, eh? | | | Projecting your failings again, or just another pathetic attempt at | trolling?

Actually, it is your inability to understand what you read that is a problem. In school, there was a subject called "reading comprehension". I guess you flunked that subject.

On Sun, 29 Mar 2009 04:09:40 -0400 Michael A. Terrell wrote: | | snipped-for-privacy@ipal.net wrote: |> |> On Fri, 27 Mar 2009 15:37:54 -0400 Michael A. Terrell wrote: |> | |> | snipped-for-privacy@ipal.net wrote: |> |>

|> |> On Wed, 25 Mar 2009 14:03:30 -0400 Michael A. Terrell wrote: |> |>

|> |> | The arcing commutator would generate so much hash that all you would |> |> | get would be a loud buzz. Any time the brush loses contact with the |> |> | armature, it arcs. |> |>

|> |> And a filter that can remove 60 Hz (or whatever slow rate was in use back in |> |> Edisn's day) could not clean up some modulated noise band at higher freqs? |> | |> | |> | Did you even read what you posted? That is one of your most pathetic |> | attempts at trolling, to date. |> |> Do you even understand filters at all? | | | Sure, from line frequency up to 11 GHZ. Ever work with Sallen-Key? | Butterworth? How about FIR filters, and using them with DSP? How about | UHF diplexers that handle over 200 KW? A filter can only do so much | with the input, or we would still be using TRF radios. IOW, you can't | make a silk purse out of a sow's ear, no matter how much you whine, or | how many hissy fits you throw.

Very good. You must have done some Googling to find all those terms.

| The only 'filter' that would work with your ridiculous pulsing DC | would be a battery bank or a band of huge electrolytics. The battery | would be a better choice, because the electrolytics would heat up quite | a bit from all the AC flowing through them.

They do make filters for smoothing out the ripple that comes from converting AC to DC. Ever tried one of those? Most of them are low pass. Raise the frequency and the filtering is more effective.

| Those arching brushes would fail every EMI/RFI standard. Do you | understand that? Or to make it even simpler for you, it would wipe out | all radio & TV OTA signals for quite a distance. If it was a large | power plant, it could be a mile or more each side of the HV distribution | lines.

I never said that arcing brushes would pass EMI/RFI standards. The subject was on the power wiring. A low pass filter would block the higher frequencies on that path. What you do on the antenna connection is anothr matter.

On Sun, 29 Mar 2009 04:13:27 -0400 Michael A. Terrell wrote: | | snipped-for-privacy@ipal.net wrote: |> |> On Fri, 27 Mar 2009 15:42:42 -0400 Michael A. Terrell wrote: |> | |> | snipped-for-privacy@ipal.net wrote: |> |>

|> |> On Wed, 25 Mar 2009 07:57:52 -0400 Michael A. Terrell wrote: |> |>

|> |> | A lot of transformerless tube radios were sold as AC/DC, and wouldn't |> |> | have worked if it was a Phil claims. You just had to make sure the |> |> | power plug was inserted the right way, or you got no B+ for the tubes. |> |>

|> |> And these were plugged into Edison's DC system? |> | |> | |> | No. They were plugged into the cigarette lighter of the flying |> | saucers at Area 51. If you are going to continue to post nonsense, I |> | might as well, too. :( |> |> I asked a question. Obviously you never provide useful answers. | | | You never post any useful questions. You just post crap, or try to | play troll, but you aren't capable of even doing that properly. WTH | would they have built AC/DC radios if they couldn't be operated on | Edison's DC generator designs? You can't be that stupid? Or can you?

Questions are not something that has utility, except for people that want to know the answers. You do not need to perceive any utility in questions that I or anyone else asks. The utility of a questions does depend on the answers is gets.

AC/DC radios could be built to operate on AC or batteries. You cannot assume ever AC/DC radio ever built was intended to operate on the kind of DC system Edison ran. It might be that they didn't engage any filtering at all for DC.

If you had simply answered the question, the conversation would move forward. Instead, you clearly have the intent to always derail conversations. Should I assume malice on your part? Or maybe just incompetence in reading English?

The history of development of these radios is unknown to me at present. Whoever came up with the idea for transformerless ac radios must have realized that it would work about as well on Edison's dc system.

As a kid, I remember getting an RCA tube manual that had a lot of information on popular tubes. It cost about 25¢. The manual included many circuits for different kinds of equipment. It included an ac/dc radio of the kind being discussed.

At that time, RCA owned most of the patents transferred to them from the likes of GE,Westinghouse, ATT, etc. It behooved RCA to come up with designs that it would license to anyone capable of paying. At that time, I did not understand the concept of licensing--it still is a mystery to me.

Among other things, there were radio articles in Popular Science. One was on how to build an ac/dc radio.

Bill

You are right However, in most areas, these were not supplied from DC. I fear that the main purpose of these sets (with filaments in series,etc) was not to make them useful for both AC and DC service ( advertising was a side issue at the time that they were popular -40's to early 50's -they came in to being long after most systems were AC) but to eliminate the cost and weight of transformers as you indicate. Cheap sets- with reversible plugs and no separate chassis grounding- did their share in reducing the gene pool (smashed case, put it in the garage or shop- good case, perch it on the bathtub).

Sure that was the whole reason they existed, the "all-american five" tube lineup as they were commonly called, transformerless series string set was a masterpiece of cost reduction. The fact that they could be operated on either AC or DC current was simply a useful side effect of that which was marketed as a feature. Nevertheless, it was a side effect that some people did make use of.

Michael A. Terrell wrote:

wrote:

wrote:

You are throwing up a problem that didn't exist because efforts to cure other problems, which were far more apparent to the operators at the time, incidentally took care of this. For a large DC generator, there would be serious performance problems with arcing (not arching) brushes- particularly under load. In extreme cases, the whole commutator could be involved- not good. First of all, brush resistance and width are designed so that current reversal (which occurs only in the coils under commutation) and is completed before the shorting of the coils in which the current was reversing was completed. In addition, at the time that this switching takes place the voltage induced in the shorted coil is near zero- the combination means no arcing. However as load changes the "neutral axis" of the machine shifts which could lead to arcing. To take care of this, the brushes of early machines could be moved to a position where arcing ceased. In later machines, interpoles were used - which added a load dependent flux in the coils under the brushes to counter this (armature reaction) effect. These replaced manual compensation about 1915-25- prior to mains powered radios. Where you get arcing and interference is where you have poorly maintained commutators and brushes, or, for cost savings, no interpole compensation or brush adjustment compensation. Where do you get this? Mainly in small and cheap "universal" (DC series) motors which can produce a lot of hash (worse on AC). The larger machines, where it was important to provide compensation would not have failed the EMI/RFI standards if they had existed at the time.

N.B. I have run multiple unfiltered 5-10HP DC motors and generators in labs in a building (without any problems with radio or near by labs depending on RF and electronics). If any sparking (as opposed to arcing) occurred, the commutator was cleaned and the brushes checked or replaced. I have been in plants where much larger DC generators are used without any problems with RF. On the other hand, I have also run into problems with a simple small 12V DC motor completely messing up radio control (incidentally, the motor was fed from an automotive battery).

The "pulsing DC" (and you are right about this being ridiculous) is something that did not occur except possibly in machines designed on the basis of "build your own DC motor" in children's "explore physics" books.

You could do these things but, in practice, it would be a rather stupid step backwards (and somehow involving changes from AC to DC, back to AC etc, ad nauseum. Inefficient and bloody expensive.

For distribution, service, utilization, and different DC voltages, there is no comparison, AC wins hands down. With regard to switching, again AC wins. For transmission- it is a balance between line and terminal costs (point to point systems, not grids) or an asynchronous connection is needed- then HVDC has advantages. These factors have been known for roughly 80 years or so. As for generation. DC is severely limited- so what do we do- generate AC (simpler, cheaper and more efficient) step it up or down with simple transformers and then use it in loads that generally don't care whether it is AC or DC or can be handled by an induction motor in a more efficient and far less complex machine than a DC machine.

So where to use DC? In those places where it provides a cost or technical advantage or a specific need for DC (long distance HV transmission, long cable systems, asynchronous links between grids, aluminum pot lines, electronic power supplies, etc.) However, for voltage level changing, switching, and most utilization, AC wins. That is a lesson that was learned over 100 years ago and modern electronics hasn't changed the situation. Wishful thinking to the contrary.

One of the largest universal motors must be the traction motors that an E-Lok (electric locomotive) has. It's 4 motors of 1 MW each, series, supplied with 700 V max, ac, 16 2/3 Hz. Newer technolgy allows them to be supplied with 50 Hz. Cetenary is 15 kV 16 2/3 Hz (old lines) and 25 kV, 50 Hz (newer lines). The AC motors have special construction to avoid arcing etc., which under these conditions would be destructive. Excitation for a 300 MW, 21 kV, 10 kA, alternator, is 220 V, 1000 A, DC. The rings that supply the DC to the alternator, are big as bricks, and usually, there's another shunt DC generator, on the same shaft, to excite the excitation (shunt DC) generator, and usually, there's also a tacho, too.

More substandard trolling?

More substandard trolling?

More substandard trolling?

More substandard trolling?

Stupid questions deserve stupid answers, when the one asking the questions is trolling.

That's it. Another fantasy, instead of doing any research.

is a wealth of early tube circuit data, including the Radiotron Designers handbook, an multiple receiving tube manuals with circuits of AA5, AC/DC radios. I know you are too arrogant and ignorant to download and read any of them, but the proof is out there.

As far as no filtering on a DC powered radio? Obviously you have never designed or repaired a radio. If there is no filtering on the DC rail, any line noise will blast through, the AVC won't work, and the radio will motorboat. Of course you will deny this, but everyone knows you are just a ham radio operator, not a tech, or an engineer.

ADmit it, Phil. You are just another lame brain troll. Any malice is on your end, in an attempt to cover your tracks on subjects you don't know.

You know, you could just filter him like I did, having done that, I don't see his posts, but I still see the useless crap you post in response to every one of them.

I'm starting to see why usenet is dying in favor of moderated discussion groups, I just wish the latter were more centralized and had a clean standardized interface.

I built one of these a bit over a half century ago- worked well. The next was a Heathkit unit that worked better (and the "paint by numbers" instructions were such that the "rats nest" situation didn't occur -if they were followed).

I built my first Heathkits over 40 years ago, starting with a couple VTVM kits. I bought one and built it. My uncle saw it, and ordered one, but decided I should build it while he talked to my dad for an hour.