Re: [Elecraft] K3 inline fuse
Good advice from you both on battery fusing, particularly in vehicles, but you've drifted off the subject a little. Chris W7CTH said: Hi, I am ready to apply 12v for the first time to my new K3. I would use a current-limited power supply to connect up ANY equipment for the first time. No fuse is as fast as electronic limiting. Even the fastest semiconductor fuses require a huge overload to achieve a sluggish response. Busman 25A fuse: 340A^2t. I'm not an expert, but divide 340 by the time you want it break and then take the square root, I think that's how it's done. So, to blow in 100ms it takes 58A. Someone put me right. UK 13A plug fuses need 2.1 x 13A to guarantee to blow in 30seconds! David G3UNA Tom, You are absolutely correct. Take a mobile situation - the radio's power ground is connected to the transceiver chassis ground, as is the coax shield, microphone shield and other stuff. All that stuff can (and will) connect to the vehicle chassis at some point. I know the coax will connect at the point where it attaches to the antenna. Now imagine a situation where the negative lead fuse is open. The vehicle chassis is still connected to the battery negative - so the radio gets it positive lead directly from the battery (since that fuse is still good), but the negative battery terminal voltage flows through the vehicle chassis to the point where the coax shield connects to the vehicle chassis (presumably at the antenna), and then follows the coax shield to the transceiver. The transceiver still works, so you (the operator) are not aware that the negative fuse has opened, but the DC current paths will give rise to strange happenings. Bottom line, follow Tom's advice and fuse only the positive lead, and in a mobile situation, take the negative voltage from the vehicle chassis close to the radio. The fusing of the negative lead started when some were concerned about the vehicle's battery to engine block (or vehicle chassis) connection is broken, which could lead to massive starting motor currents being conducted from the coax ground at the mobile antenna, through the radio, and onto the battery negative terminal. Yes, that situation is quite real, but can be circumvented by periodically checking the engine block to chassis grounding in the vehicle, as well as the battery negative connection to the vehicle chassis. If the radio has an isolated (floating) negative connection (I believe only commercial mobile radios do that), then fusing of the negative lead is OK, but for most ham radios, the fusing of the negative lead can cause as much damage as the reasons given for inserting a fuse into the negative lead. Take your pick. 73, Don W3FPR Tom W8JI wrote: Positive lead fuses are a good idea. Negative lead fuses never were a good idea unless the radio has a totally floating negative buss. If the negative lead fuse to the radio opens for any reason all the negative lead current for the radio will flow through the negative lead of any accessories connected to the power supply. They are a terrible idea for any system with the negative lead common to ports in and out of the radio, or to the chassis. You certainly won't catch me using one!The negative lead needs to be connected solidly to the power supply negative for a multitude of reasons, the most prominent of which is if the negative lead fuse to the radio opens you can blow up accessories or open ground traces including traces in the radio. They are not even recommended in vehicles any longer in some countries because of the fire and damage hazard they create. 73 Tom __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
David Cutter wrote: I would use a current-limited power supply to connect up ANY equipment for the first time. No fuse is as fast as electronic limiting. Even the fastest semiconductor fuses require a huge overload to achieve a sluggish response. Busman 25A fuse: 340A^2t. I'm not an expert, but divide 340 by the time you want it break and then take the square root, I think that's how it's done. So, to blow in 100ms it takes 58A. Someone put me right. UK 13A plug fuses need 2.1 x 13A to guarantee to blow in 30seconds! The other important point is that fuses provide ZERO protection until AFTER they have blown. In the life and death of a semiconductor, even a few milliseconds is a very long time indeed. -- 73 from Ian GM3SEK http://www.ifwtech.co.uk/g3sek __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
I did not have a current-limited power supply. Just a Astrom rs-35m. anyway I just went for it and everything worked out okay. all my ohm reading were all in the safe range and I did take my time to make sure I did eveything right. K3 turned on okay. Chris From: David Cutter d.cut...@ntlworld.com To: d...@w3fpr.com; Tom W8JI w...@w8ji.com Cc: elecraft@mailman.qth.net; Chris Hembree w7...@yahoo.com Sent: Fri, August 13, 2010 12:33:33 AM Subject: Re: [Elecraft] K3 inline fuse Good advice from you both on battery fusing, particularly in vehicles, but you've drifted off the subject a little. Chris W7CTH said: Hi, I am ready to apply 12v for the first time to my new K3. I would use a current-limited power supply to connect up ANY equipment for the first time. No fuse is as fast as electronic limiting. Even the fastest semiconductor fuses require a huge overload to achieve a sluggish response. Busman 25A fuse: 340A^2t. I'm not an expert, but divide 340 by the time you want it break and then take the square root, I think that's how it's done. So, to blow in 100ms it takes 58A. Someone put me right. UK 13A plug fuses need 2.1 x 13A to guarantee to blow in 30seconds! David G3UNA Tom, You are absolutely correct. Take a mobile situation - the radio's power ground is connected to the transceiver chassis ground, as is the coax shield, microphone shield and other stuff. All that stuff can (and will) connect to the vehicle chassis at some point. I know the coax will connect at the point where it attaches to the antenna. Now imagine a situation where the negative lead fuse is open. The vehicle chassis is still connected to the battery negative - so the radio gets it positive lead directly from the battery (since that fuse is still good), but the negative battery terminal voltage flows through the vehicle chassis to the point where the coax shield connects to the vehicle chassis (presumably at the antenna), and then follows the coax shield to the transceiver. The transceiver still works, so you (the operator) are not aware that the negative fuse has opened, but the DC current paths will give rise to strange happenings. Bottom line, follow Tom's advice and fuse only the positive lead, and in a mobile situation, take the negative voltage from the vehicle chassis close to the radio. The fusing of the negative lead started when some were concerned about the vehicle's battery to engine block (or vehicle chassis) connection is broken, which could lead to massive starting motor currents being conducted from the coax ground at the mobile antenna, through the radio, and onto the battery negative terminal. Yes, that situation is quite real, but can be circumvented by periodically checking the engine block to chassis grounding in the vehicle, as well as the battery negative connection to the vehicle chassis. If the radio has an isolated (floating) negative connection (I believe only commercial mobile radios do that), then fusing of the negative lead is OK, but for most ham radios, the fusing of the negative lead can cause as much damage as the reasons given for inserting a fuse into the negative lead. Take your pick. 73, Don W3FPR Tom W8JI wrote: Positive lead fuses are a good idea. Negative lead fuses never were a good idea unless the radio has a totally floating negative buss. If the negative lead fuse to the radio opens for any reason all the negative lead current for the radio will flow through the negative lead of any accessories connected to the power supply. They are a terrible idea for any system with the negative lead common to ports in and out of the radio, or to the chassis. You certainly won't catch me using one!The negative lead needs to be connected solidly to the power supply negative for a multitude of reasons, the most prominent of which is if the negative lead fuse to the radio opens you can blow up accessories or open ground traces including traces in the radio. They are not even recommended in vehicles any longer in some countries because of the fire and damage hazard they create. 73 Tom __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
On Fri, 13 Aug 2010 11:08:04 +0100, Ian White GM3SEK wrote: The other important point is that fuses provide ZERO protection until AFTER they have blown. In the life and death of a semiconductor, even a few milliseconds is a very long time indeed. Yes. On the other hand, boards are all pre-tested at the factory, and assembly instructions included several resistance checks, which I suspect are carefully selected to expose any faults that may have happened during assembly. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
Ian wrote... The other important point is that fuses provide ZERO protection until AFTER they have blown. In the life and death of a semiconductor, even a few milliseconds is a very long time indeed. I like to tell the story about a series of tests we did when I worked at Fairchild, in Silicon Valley. Our little VHF silicon transistors were very expensive, and quite fragile. We tested many fuses to identify which one(s) would be suitable protection for the transistors. To summarize: transistors are a very effective way of protecting fuses! 73, George T Daughters, K6GT CU in the California QSO Party (CQP) October 2-3, 2010 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
A transistor is the fastest fuse on 3 legs, beats a 2-legged fuse any day. David G3UNA I like to tell the story about a series of tests we did when I worked at Fairchild, in Silicon Valley. Our little VHF silicon transistors were very expensive, and quite fragile. We tested many fuses to identify which one(s) would be suitable protection for the transistors. To summarize: transistors are a very effective way of protecting fuses! 73, George T Daughters, K6GT CU in the California QSO Party (CQP) October 2-3, 2010 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
The transistor is the most probable reason for the fuse blowing but the fuse may save the other components and semi conductors as well as the circuit board. The original query stated he would be using an Astron 35 which has a current limiter but limiting the current to 35 amps will still allow a lot of damage. Sent from my iPhone On Aug 13, 2010, at 9:55, gdaug...@stanford.edu wrote: Ian wrote... The other important point is that fuses provide ZERO protection until AFTER they have blown. In the life and death of a semiconductor, even a few milliseconds is a very long time indeed. I like to tell the story about a series of tests we did when I worked at Fairchild, in Silicon Valley. Our little VHF silicon transistors were very expensive, and quite fragile. We tested many fuses to identify which one(s) would be suitable protection for the transistors. To summarize: transistors are a very effective way of protecting fuses! 73, George T Daughters, K6GT CU in the California QSO Party (CQP) October 2-3, 2010 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse current limiting
If you do not have an **adjustable** current limited supply, do what I do on the bench. I have a 35 amp limited supply on the bench, and my 13.8 volt buss has jacks that are direct, through a 10 ohm 10 watt resistor, and through a second 10 ohm in series with that. I can get a really good idea if something is going to power up OK because I can start with 20 ohms, move the tap to 10 ohms, and then add a jumper plug to make it 5 ohms. My supply also is variable voltage, and although it only goes down to 9 volts (and up to 18) that still helps. Many things do not show with a resistance test, but a resistor limited test will show problems with popping bigger transistors or foil traces. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
One thing that hasn't been mentioned is that the K3 has a built-in 6A fuse for the basic rig and a separate 20A circuit breaker for the KPA3. So it's not like there's no protection at all between the APP connector and the internal circuits. 73 -- Joe KB8AP On Aug 13, 2010, at 9:02 AM, Willis wrote: The transistor is the most probable reason for the fuse blowing but the fuse may save the other components and semi conductors as well as the circuit board. The original query stated he would be using an Astron 35 which has a current limiter but limiting the current to 35 amps will still allow a lot of damage. Sent from my iPhone On Aug 13, 2010, at 9:55, gdaug...@stanford.edu wrote: Ian wrote... The other important point is that fuses provide ZERO protection until AFTER they have blown. In the life and death of a semiconductor, even a few milliseconds is a very long time indeed. I like to tell the story about a series of tests we did when I worked at Fairchild, in Silicon Valley. Our little VHF silicon transistors were very expensive, and quite fragile. We tested many fuses to identify which one(s) would be suitable protection for the transistors. To summarize: transistors are a very effective way of protecting fuses! 73, George T Daughters, K6GT CU in the California QSO Party (CQP) October 2-3, 2010 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
Amen! Best so far. Let´s move on. / James - On 2010-08-13 17:01, David Cutter wrote: A transistor is the fastest fuse on 3 legs, beats a 2-legged fuse any day. David G3UNA I like to tell the story about a series of tests we did when I worked at Fairchild, in Silicon Valley. Our little VHF silicon transistors were very expensive, and quite fragile. We tested many fuses to identify which one(s) would be suitable protection for the transistors. To summarize: transistors are a very effective way of protecting fuses! 73, George T Daughters, K6GT CU in the California QSO Party (CQP) October 2-3, 2010 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
You are much better off using the current limiting feature of your dc supply. A fuse is not fast enough to protect any electronic circuitry. Strictly speaking a fuse in line is rated to protect the cable in the event of a short circuit in the rig which would be a very big fuse, far bigger than your psu is rated to supply most likely. Fuses and their holders are too slow and drop valuable volts along with the cable drop and connectors, which all add up to a poorer distortion figure on transmit. David G3UNA Hi, I am ready to apply 12v for the first time to my new K3. Should I have a inline fuse on the DC to the K3? and if so what amp. Just don't look right not to have a fuse inline. Thanks Chris W7CTH __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
I completely agree with you. The inline fuses are there for mobile installations where you have a direct connection to the car battery. On my ICOM radios I have always shortened the power cable removing the inline fuse in the process. AB2TC - Knut David Cutter wrote: You are much better off using the current limiting feature of your dc supply. A fuse is not fast enough to protect any electronic circuitry. Strictly speaking a fuse in line is rated to protect the cable in the event of a short circuit in the rig which would be a very big fuse, far bigger than your psu is rated to supply most likely. Fuses and their holders are too slow and drop valuable volts along with the cable drop and connectors, which all add up to a poorer distortion figure on transmit. David G3UNA snip -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-inline-fuse-tp5414371p5418061.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
Follow the instructions and check the + terminal to - with an ohm meter for any shorts. The problem you face is the transistor is the worlds fastest fuse and on initial turn on you are looking at a low current surge as the unit charges the supply and decoupling caps. A full current rated fuse will not protect the PCB if you did something wrong, nor will current limit if set for the max current the K3 will draw on transmit. If you test the resistance first, the chances are you will be safe on initial power up. Like one suggested using a current limiting PS set say at 3 amps, that will protect you adequately. When the K3 comes alive, you can increase the current limit to operating conditions. I hope this helps. Mel --- On Thu, 8/12/10, ab2tc ab...@arrl.net wrote: From: ab2tc ab...@arrl.net Subject: Re: [Elecraft] K3 inline fuse To: elecraft@mailman.qth.net Date: Thursday, August 12, 2010, 3:13 PM I completely agree with you. The inline fuses are there for mobile installations where you have a direct connection to the car battery. On my ICOM radios I have always shortened the power cable removing the inline fuse in the process. AB2TC - Knut David Cutter wrote: You are much better off using the current limiting feature of your dc supply. A fuse is not fast enough to protect any electronic circuitry. Strictly speaking a fuse in line is rated to protect the cable in the event of a short circuit in the rig which would be a very big fuse, far bigger than your psu is rated to supply most likely. Fuses and their holders are too slow and drop valuable volts along with the cable drop and connectors, which all add up to a poorer distortion figure on transmit. David G3UNA snip -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-inline-fuse-tp5414371p5418061.html Sent from the [K3] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
The best method is Wayne's suggestion from way back: In both Neg and Pos leads, supply a fuseholder and fuse. I use the stubby fuses from Motorola @ 30A, you should use something like that. These are T-rated, meaning they're designed to open with a DC load. Don't use a fuse out of your home's fusebox... General setup: 12V AGM Battery @ 110 AH, cabled to a set of panel-mounted MOT inline fuse holders. Each lead is covered by a 30A fuse. The battery is charged by solar power, two Siemens SR50 (50W) panels on the roof of the shack. Note: This recommendation is a little more permanent than what you're probably looking for right now. If you're interested in this approach, I can probably get you the part numbers you need. MOT has a service center in IL, and you can phone in your order. 73, matt W6NIA On Wed, 11 Aug 2010 16:32:12 -0700 (PDT), you wrote: Hi, I am ready to apply 12v for the first time to my new K3. Should I have a inline fuse on the DC to the K3? and if so what amp. Just don't look right not to have a fuse inline. Thanks Chris W7CTH __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
Positive lead fuses are a good idea. Negative lead fuses never were a good idea unless the radio has a totally floating negative buss. If the negative lead fuse to the radio opens for any reason all the negative lead current for the radio will flow through the negative lead of any accessories connected to the power supply. They are a terrible idea for any system with the negative lead common to ports in and out of the radio, or to the chassis. You certainly won't catch me using one!The negative lead needs to be connected solidly to the power supply negative for a multitude of reasons, the most prominent of which is if the negative lead fuse to the radio opens you can blow up accessories or open ground traces including traces in the radio. They are not even recommended in vehicles any longer in some countries because of the fire and damage hazard they create. 73 Tom In both Neg and Pos leads, supply a fuseholder and fuse. I use the stubby fuses from Motorola @ 30A, you should use something like that. These are T-rated, meaning they're designed to open with a DC load. Don't use a fuse out of your home's fusebox... __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
Tom, You are absolutely correct. Take a mobile situation - the radio's power ground is connected to the transceiver chassis ground, as is the coax shield, microphone shield and other stuff. All that stuff can (and will) connect to the vehicle chassis at some point. I know the coax will connect at the point where it attaches to the antenna. Now imagine a situation where the negative lead fuse is open. The vehicle chassis is still connected to the battery negative - so the radio gets it positive lead directly from the battery (since that fuse is still good), but the negative battery terminal voltage flows through the vehicle chassis to the point where the coax shield connects to the vehicle chassis (presumably at the antenna), and then follows the coax shield to the transceiver. The transceiver still works, so you (the operator) are not aware that the negative fuse has opened, but the DC current paths will give rise to strange happenings. Bottom line, follow Tom's advice and fuse only the positive lead, and in a mobile situation, take the negative voltage from the vehicle chassis close to the radio. The fusing of the negative lead started when some were concerned about the vehicle's battery to engine block (or vehicle chassis) connection is broken, which could lead to massive starting motor currents being conducted from the coax ground at the mobile antenna, through the radio, and onto the battery negative terminal. Yes, that situation is quite real, but can be circumvented by periodically checking the engine block to chassis grounding in the vehicle, as well as the battery negative connection to the vehicle chassis. If the radio has an isolated (floating) negative connection (I believe only commercial mobile radios do that), then fusing of the negative lead is OK, but for most ham radios, the fusing of the negative lead can cause as much damage as the reasons given for inserting a fuse into the negative lead. Take your pick. 73, Don W3FPR Tom W8JI wrote: Positive lead fuses are a good idea. Negative lead fuses never were a good idea unless the radio has a totally floating negative buss. If the negative lead fuse to the radio opens for any reason all the negative lead current for the radio will flow through the negative lead of any accessories connected to the power supply. They are a terrible idea for any system with the negative lead common to ports in and out of the radio, or to the chassis. You certainly won't catch me using one!The negative lead needs to be connected solidly to the power supply negative for a multitude of reasons, the most prominent of which is if the negative lead fuse to the radio opens you can blow up accessories or open ground traces including traces in the radio. They are not even recommended in vehicles any longer in some countries because of the fire and damage hazard they create. 73 Tom In both Neg and Pos leads, supply a fuseholder and fuse. I use the stubby fuses from Motorola @ 30A, you should use something like that. These are T-rated, meaning they're designed to open with a DC load. Don't use a fuse out of your home's fusebox... __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] K3 inline fuse
On 8/11/2010 6:32 PM, Chris Hembree wrote: Hi, I am ready to apply 12v for the first time to my new K3. Should I have a inline fuse on the DC to the K3? and if so what amp. Just don't look right not to have a fuse inline. Thanks Chris W7CTH __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html If you have one, it probably would not hurt to do so. I put one on mine just in case. john km5ps __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
