Hallicrafter's Tour on Film [25 Hz power]
"Richard Knoppow" wrote in message
... 25hz is used for industrial purposes, particularly for electric railways because core losses are lower in motors and transformers (less heat dissipated). Richard, I believe the real reason for 25 Hz power near Niagara Falls was the large number of chlor-alkali plants in the area. The Castner Electrolytic Alkali Company began operation at Niagara Falls in 1897. Eventually this became the Olin Niachlor plant. Chlor-alkali plants are a major consumer of electricity, and it was plentiful and cheap at Niagara Falls. Other companies in the same area with chlor-alkali plants are DuPont and Hooker (later to be Occidental Chemical). The reason for using 25 Hz AC is related to the need for high current DC for use in the process. In the early days, mechanical (rotary) rectifiers were used to convert the AC to DC. Essentially a synchronous motor was used to turn large disks broken into sections. AC was fed to these disks. Brushes would rub on the disk producing a unipolar output. Operating at 1500 RPM this system was quite efficient. But at 50 or 60 Hz, rotating the disks at 3000 or 3600 RPM, the efficiency was less (the off time, essentially the insulating space between the disk sections, became a larger portion of the total period) and the brushes wore out faster. Operating at lower frequencies would have been even more efficient but transformer size became excessive. Unfortunately the early electrolytic cells used mercury for one electrode leading to a major pollution problem. You might recognize the name Hooker Chemical from their waste being dumped in the Love Canal. 73, Dr. Barry L. Ornitz WA4VZQ |
Hallicrafter's Tour on Film
On Wed, 8 Apr 2009 09:39:03 +0100, "Roger Basford" Roger at new-gate
dot co dot uk wrote: "Jon Teske" wrote in message .. . I'm going a vague memory here, but one of the fellows did look like Bill Halligan who 10 years later was often pictured in Hallicrafter's ads. I remember he had a two letter suffix in his call and for some reason I thought it was W9AN. See www.geocities.com/w8jyz/W9AC.pdf Thanks Roger for that link. I wonder how he pulled off that two letter call suffix having had a three letter one before. That must have been quite rare or perhaps some sort of "reward" for his WW II engineering service. I have no idea how that worked in those days. By the time I got into radio (1956 as a teen) two letter suffixes were VERY rare in the US until they became available as a sort of reward for having the Extra Class and a certain amount of longevity. Later they became available as a "vanity" program in conjuction with holding certain classes of license. 1X2 calls don't seem to become available very often now. Allowing for changes in eyeglasses and a bit of aging, it does appear that the fellow pictured in your link is the same guy I think was Halligan in the movie. I knew one fellow who had worked with him during the war and he said that Bill Halligan was a real gentleman and a brilliant engineer. Jon Teske, W3JT |
Hallicrafter's Tour on Film [25 Hz power]
On Wed, 8 Apr 2009 21:26:07 -0400, "Phred" wrote:
"Richard Knoppow" wrote in message ... 25hz is used for industrial purposes, particularly for electric railways because core losses are lower in motors and transformers (less heat dissipated). Richard, I believe the real reason for 25 Hz power near Niagara Falls was the large number of chlor-alkali plants in the area. The Castner Electrolytic Alkali Company began operation at Niagara Falls in 1897. Eventually this became the Olin Niachlor plant. Chlor-alkali plants are a major consumer of electricity, and it was plentiful and cheap at Niagara Falls. Other companies in the same area with chlor-alkali plants are DuPont and Hooker (later to be Occidental Chemical). The reason for using 25 Hz AC is related to the need for high current DC for use in the process. In the early days, mechanical (rotary) rectifiers were used to convert the AC to DC. Essentially a synchronous motor was used to turn large disks broken into sections. AC was fed to these disks. Brushes would rub on the disk producing a unipolar output. Operating at 1500 RPM this system was quite efficient. But at 50 or 60 Hz, rotating the disks at 3000 or 3600 RPM, the efficiency was less (the off time, essentially the insulating space between the disk sections, became a larger portion of the total period) and the brushes wore out faster. Operating at lower frequencies would have been even more efficient but transformer size became excessive. Unfortunately the early electrolytic cells used mercury for one electrode leading to a major pollution problem. You might recognize the name Hooker Chemical from their waste being dumped in the Love Canal. 73, Dr. Barry L. Ornitz WA4VZQ I vaguely remember my father (an electrician) telling me that power at the very beginning of WW II in the Gary Indiana area was 25 Hz. Does anyone know anything about that? Would the presence of steel mills and other heavy industry have anything to do with it. I have no reason to doubt what my father had said (but I can't ask him anymore.) Were there other places in the US that had non standard Hz. Also I'd be interested in knowing when 60 Hz became the US standard and why? The Gary, Hammond, East Chicago area and Southern parts of nearby Chicago is, of course, one of the more heavily industrialized areas in the US, or at least it was in the first half of the 20th century. Gary (which happens to be my birthplace though I only lived there 10 weeks, at the beginning of WW II) was founded specifically as a "Company Town" in 1906 for US Steel and is named for an early president of the company. Jon Teske, W3JT [And as I found out on the only visit I ever made to Gary aside from bypassing it on the tollways when I stopped to get an Indiana Birth Certificate, my claim to fame is that I was born in the same hospital as the Jackson family kids...Michael, Janet, Tito etc. Sheesh! ] |
Hallicrafter's Tour on Film
Anybody notice any audio-video sync problems in the MP4
version? I tried two different players and the track was way off. I'm going to download the MPeg2 version and see how that plays... Jim On Sat, 4 Apr 2009 18:30:48 -0700, "Richard Knoppow" wrote: I found a tour of the Hallicrafter's plant on line. This is a WW-2 propaganda film, dated 1944 and titled "Voice of Victory". In two parts at http://www.archive.org It has considerable detail on the construction of the BC-610 and shows some other products in somewhat less detail. |
Hallicrafter's Tour on Film
"Jim" wrote in message ... Anybody notice any audio-video sync problems in the MP4 version? I tried two different players and the track was way off. So is my Verizon Fiber TV box running my NTSC TV. Paul P. |
Hallicrafter's Tour on Film
Jim wrote:
Anybody notice any audio-video sync problems in the MP4 version? I tried two different players and the track was way off. How can you tell? From what I remembered and a quick review, the only place there could be synchronized sound is at the begining with the ham who was later identifed as the chief engineer of Halicrafters (Samuelson) "on the air" and the speech at the end of the second part by the head of the Signal Corps. They were both fine with my playing them using QuickTime player and VLC under MacOS. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
Hallicrafter's Tour on Film
http://library.duke.edu/digitalcolle...R0111-lrg.jpeg
Looks like their letterhead circa 1945. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
Hallicrafter's Tour on Film
"Geoffrey S. Mendelson" wrote in message ... http://library.duke.edu/digitalcolle...R0111-lrg.jpeg Looks like their letterhead circa 1945. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM Sure does look like a letterhead although letterheads usually also have phone numbers and cable addresses on them. There is a copyright notice below the word "radio" indicating 1945 and the pictures feature the mobile radio station from the movie (forgot the SCR number) with an E for Efficiency banner, also the SX-28, probably the best known H product of the time. I wonder what the original source was. -- Richard Knoppow Los Angeles WB6KBL |
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