Home |
Search |
Today's Posts |
#11
|
|||
|
|||
Hammarlund HX-50 choke question.
Scott Dorsey wrote:
Chuck Harris wrote: Scott Dorsey wrote: Chuck Harris wrote: But that is exactly backwards from the way chokes work. As the current rises, and the core approaches saturation, the coil starts to lose the inductance enhancement provided by the core, and it approaches the inductance of an equivalent air core choke. That is, the inductance *drops*, and the inductive reactance *drops* and the AC current shoots way up. That makes perfect sense to me. So how _do_ current-limiting chokes work, then? I always assumed they worked as I described but I may well be wrong. On DC, they can't! No way, no how. Right, but I was thinking that in the position where that coil is in the circuit, it's directly in series with the AC coming off the transformer. On AC, a choke can limit the current by being a reactive component... kind of a lossless resistor for AC. But! Swinging chokes always reduce their inductance when the current rises. They typically have a 100:1 change in inductance over their design current range. How does the reduced inductance translate to higher series impedance? It doesn't. Where did you get the idea that such an inductor exists? A swinging choke aids in the *voltage* regulation of a choke input power supply by having a high inductive reactance at low currents (where the supply would tend to be too high in voltage), and having low inductive reactance at high currents (where the supply would normally tend to droop.) Is that what you are thinking of? -Chuck |
#12
|
|||
|
|||
Hammarlund HX-50 choke question.
Chuck Harris wrote:
A swinging choke aids in the *voltage* regulation of a choke input power supply by having a high inductive reactance at low currents (where the supply would tend to be too high in voltage), and having low inductive reactance at high currents (where the supply would normally tend to droop.) Is that what you are thinking of? Ahh! So the increased current causes the inductive reactance to drop, causing the series impedance to drop. That makes sense, so long as the source impedance is the same all the time, right? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#13
|
|||
|
|||
Hammarlund HX-50 choke question.
Scott Dorsey wrote:
Chuck Harris wrote: A swinging choke aids in the *voltage* regulation of a choke input power supply by having a high inductive reactance at low currents (where the supply would tend to be too high in voltage), and having low inductive reactance at high currents (where the supply would normally tend to droop.) Is that what you are thinking of? Ahh! So the increased current causes the inductive reactance to drop, causing the series impedance to drop. That makes sense, so long as the source impedance is the same all the time, right? --scott If the source impedance changed, it could either help, or hurt the process. It would all depend on how it changed. But I would expect that for the usual diode, and transformer combination, the source impedance should be pretty stable. For a swinging choke to work, the power supply must be choke input. It is necessary that the choke see the massive AC ripple that comes out of the rectifier. No ripple, no regulating effect from the reactance. -Chuck |
#14
|
|||
|
|||
Hammarlund HX-50 choke question.
Chuck Harris wrote:
For a swinging choke to work, the power supply must be choke input. It is necessary that the choke see the massive AC ripple that comes out of the rectifier. No ripple, no regulating effect from the reactance. Okay, wait a second. You're talking about a configuration where the choke is seeing both AC and DC on it, and both are required for regulation. The impressed AC is modulated by the DC, correct? As the DC voltage changes, the inductance changes, so the reactive part of the impedance changes and the AC voltage changes. Do I have that right? I was thinking about a configuration where the choke sees entirely AC, which would be a different thing altogether, like you see in arc lamp power supplies. I thought they worked the same way but it's clear they don't. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#15
|
|||
|
|||
Hammarlund HX-50 choke question.
Its Alive!!!
http://www.ppinyot.com/hammarlund.htm More work to be done but it now makes heat into a dummy load. Thanks for all the suggestions. Paul. |
#16
|
|||
|
|||
Hammarlund HX-50 choke question.
"Paul P" wrote in message news:WbPDh.1220$JB2.1177@trnddc07... Its Alive!!! http://www.ppinyot.com/hammarlund.htm More work to be done but it now makes heat into a dummy load. Thanks for all the suggestions. Paul. Congratulations!!! Sometimes it takes quite a bit of digging to discover what's wrong. -- --- Richard Knoppow Los Angeles, CA, USA -- Posted via a free Usenet account from http://www.teranews.com |
#17
|
|||
|
|||
FU Hammarlund Testing later this week on FreeWheeler's net.
If all goes well with the alignment, I should be on next week, with this
rig, testing on the FreeWheelers Net 10:30 pm central 3.916 LSB. That band's crystal is working good. Paul KB3LZP |
#18
|
|||
|
|||
FU Hammarlund Testing later this week on FreeWheeler's net.
On Feb 24, 4:18 pm, "Paul P"
wrote: If all goes well with the alignment, I should be on next week, with this rig, testing on the FreeWheelers Net 10:30 pm central 3.916 LSB. That band's crystal is working good. Paul KB3LZP What, besides the other option does FU mean? |
#19
|
|||
|
|||
FU Hammarlund Testing later this week on FreeWheeler's net.
On 25 Feb 2007 00:14:00 -0800, "Steven"
wrote: On Feb 24, 4:18 pm, "Paul P" wrote: If all goes well with the alignment, I should be on next week, with this rig, testing on the FreeWheelers Net 10:30 pm central 3.916 LSB. That band's crystal is working good. Paul KB3LZP What, besides the other option does FU mean? LOL. Probably "follow-up", or maybe "full-up" testing... Dale I have plenty of FU boatanchors |
#20
|
|||
|
|||
FU Hammarlund Testing later this week on FreeWheeler's net.
On Feb 25, 3:15 am, Dale Carlson wrote:
On 25 Feb 2007 00:14:00 -0800, "Steven" wrote: On Feb 24, 4:18 pm, "Paul P" wrote: If all goes well with the alignment, I should be on next week, with this rig, testing on the FreeWheelers Net 10:30 pm central 3.916 LSB. That band's crystal is working good. Paul KB3LZP What, besides the other option does FU mean? LOL. Probably "follow-up", or maybe "full-up" testing... Dale I have plenty of FU boatanchors Not the -BAR kind I hope. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Feb 23 is the No-code date | Policy | |||
Antenna RF choke questions | Antenna | |||
Choke Balun Torture | Antenna | |||
Hammarlund HX50 6DQ5 Plate choke question. | Boatanchors | |||
Hammarlund hq 100 choke info | Boatanchors |