[Drakelist] REDUCED: USA Made Power Resistors
FOR SALE: USA made Power Resistors Suitable for bleeder resistors in HV power supplies, etc. These are good quality, new old stock parts. QTY 1 each. Now reduced - $6.00 to $18.00 each. Picture and ordering page at: http://www.af4k.com/resistors.htm 50,000 ohms at 100 watts 25,000 ohms w/slider at 100 watts 25,000 ohms at 100 watts 25,000 ohms at 75 watts 25,000 ohms at 50 watts 24,000 ohms at 72 watts 20,000 ohms at 100 watts 20,000 ohms at 50 watts 18,000 ohms at 86 watts 18,000 ohms at 55 watts 16,000 ohms at 50 watts 15,000 ohms at 120 watts 15,000 ohms at 72 watts 14,000 ohms at 50 watts (QTY 2) 12,000 ohms at 116 watts 12,000 ohms at 75 watts 12,000 ohms at 68 watts 12,000 ohms at 40 watts 12,000 ohms at 30 watts Picture and ordering page at: http://www.af4k.com/resistors.htm ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Light bulb for inrush currrent protection.
Has anyone heard any additional information about using a light bulb in the AC line ahead of your radios ac input to reduce the inrush current to the rigs as they are turned on. I would like to hear more about doing that if the information is available. It seems there is quit a surge when I turn on the transmitter Drake T4xB. Thanks 73 de Fred WD8ADG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Light bulb for inrush currrent protection.
Fred - That technique is normally done when troubleshooting a 'new' piece of gear to protect power transformers, etc. when a radio is in unknown condition. It's really not indicated for operation. The AC-4 power supplies all THUMP at turn-on, depending upon where the AC waveform is at the instant the switch closes. I've never seen a bad transformer in an AC-4 that hadn't been destroyed by too big a fuse or other mis-treatment. The 'correct' fix is a 'thermistor', or 'inrush current limiter', which is a device shaped like a large disc ceramic capacitor. It is a temperature dependent resistor that has a specific resistance when cold, that drops considerably when it heats up from the current through it. They are not expensive, but do get quite warm in operation, and of course affect power supply regulation. Selecting the appropriate one is a bit of a pain, you want one that starts out high enough to limit that initial inrush current, yet drops to a low enough resistance when hot to minimize regulation. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com fjmel...@aol.com wrote: /Has anyone heard any additional information about using a light bulb in the AC line ahead of your radios ac input to reduce the inrush current to the rigs as they are turned on. I would like to hear more about doing that if the information is available. It seems there is quit a surge when I turn on the transmitter Drake T4xB./ // /Thanks / /73 de Fred WD8ADG / ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Light bulb for inrush currrent protection.
A light bulb is not the way to go as its resistance is very low when cold and goes higher with temperature. That is the reverse of what you want for an inrush current limiter. If you really need to do this you will need the appropriate thermister. 73, Alan - Original Message - From: fjmel...@aol.com To: drakelist@zerobeat.net Sent: Wednesday, January 26, 2011 9:35 AM Subject: Re: [Drakelist] Drakelist Digest,Light bulb for inrush currrent protection. Has anyone heard any additional information about using a light bulb in the AC line ahead of your radios ac input to reduce the inrush current to the rigs as they are turned on. I would like to hear more about doing that if the information is available. It seems there is quit a surge when I turn on the transmitter Drake T4xB. Thanks 73 de Fred WD8ADG -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Want to buy...
Hi, If anyone has a set of T4anything and R4anything that they want to sell please email me and let me know what you need for them. I do not need a power supply and the cases do not have to be in flawless conditions since I can just repaint them. If you don't have those perhaps you have a TR4 or TR4C or CW that you would like to part with. I would be interested in either the pair of radios or a TR4, TR4C or TR4CW. Thanks Kevin Elliott I am about ready to get rid of my Kenwood TS-2000 and get all tube radios, the sound quality of my TR4 finds me using it far more than my 2000. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Light bulb for inrush currrent protection.
On Wed, 26 Jan 2011 13:22:47 -0500, Garey Barrell wrote: The 'correct' fix is a 'thermistor', or 'inrush current limiter', which is a device shaped like a large disc ceramic capacitor. Usually flat black in color, often called an NTC because of the negative temperature coefficient. Selecting the appropriate one is a bit of a pain, you want one that starts out high enough to limit that initial inrush current, yet drops to a low enough resistance when hot to minimize regulation. I find that units salvaged from scrap PC power supplies are often a decent size for your average tube rig. Some of them have markings on them that can be Googled for the specs. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Light bulb for inrush currrent protection.
On Wed, 26 Jan 2011 12:35:45 EST, fjmel...@aol.com wrote: Has anyone heard any additional information about using a light bulb in the AC line ahead of your radios ac input to reduce the inrush current to the rigs as they are turned on. I would like to hear more about doing that if the information is available. It seems there is quit a surge when I turn on the transmitter Drake T4xB. I actually saw the lightbulb idea in an old magazine. The idea was to use a delay relay in the power supply to bypass the light bulb after the PS has come up part way. It works, but as Garey pointed out, there are alternatives. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
