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OT How to size a diode?
I am fabricating a small box that will house a couple of "muffin" fans
to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks |
OT How to size a diode?
wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks What kind of fans are you using? 20W sounds like AC motors. If so, you do not want diodes. What you need is the right switch, or a two pole four postion rotary switch wired to give the function you want. Another way is the switch used in range hoods, or just a pair of SPST switches, one for each fan. You may need a metal flap to block the unused fan to keep the hot air from being pushed back through it. -- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated. |
OT How to size a diode?
On Jan 24, 12:07*pm, wrote:
I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. *I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. *I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. *I am having a bit of trouble with selecting a diode. *I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. *The fans draw 20W each. *For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: *http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. *Recommendations please. *Once I complete this task I can get down to forming the sheetmetal. *Thanks |
OT How to size a diode?
I might be missing something here , but why not just use 2 spst
switches and then you can run either fan , both fans, or none. |
OT How to size a diode?
wrote:
I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks You don't neet a diode, you need a switch. Specifically, a DPDT Center-off switch. Ground out both fans, and use the switch to switch the hot. Here is a picture of how you would wire it up: http://img510.imageshack.us/img510/9725/dpdtfan.jpg As you didn't provide specifications for your fans, determining the correct ratings (and size and mounting hole) for your switch is up to you. Personally, I would order it online and get the switch you want, instead of buying whatever radio shack has laying around made by God only knows who. Jon |
OT How to size a diode?
On Mon, 24 Jan 2011 13:17:46 -0800, "Jon Danniken"
wrote: wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks You don't neet a diode, you need a switch. Specifically, a DPDT Center-off switch. Ground out both fans, and use the switch to switch the hot. Here is a picture of how you would wire it up: http://img510.imageshack.us/img510/9725/dpdtfan.jpg As you didn't provide specifications for your fans, determining the correct ratings (and size and mounting hole) for your switch is up to you. Personally, I would order it online and get the switch you want, instead of buying whatever radio shack has laying around made by God only knows who. Jon IF he is running DC fans a center off double throw single pole switch will work with a diode. With the diode connected between the positive connections, and the negatives tied together, putting power to one side of the diode will run the one motor, with current to the other fan being blocked by the diode. Put power to the other side of the diode and the first fan will run through the diode, and the second fan will run full power. Not a bad way to do things - and the diode just needs to handle adequate voltage and current for one motor. If the fans are 12 volt, he needs a 25 voltpiv, 2 amp diode at the very minimum. I'd use a 50 volt 5 or 10 amp diode if I was doing it. The 3 amp barrel diode on the rat-shack site would do the job. It doesn't say on that site, but it is a 50 volt PIV diode. (some are actually 200PIV) - look up ecg-5800 for 50 volt,5801 is 100 volt, 5802 is 200 volt. A 6 amp diode would be a 5850, 5854, or 5855 and would be a stud-mount.(DO4 case) |
OT How to size a diode?
Inscribed thus:
I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks Go grab an old computer PSU and strip one of the low voltage diodes out ! -- Best Regards: Baron. |
OT How to size a diode?
Jon Danniken wrote:
You don't neet a diode, you need a switch. Specifically, a DPDT Center-off switch. Often described in the online catalogs as a DPDT ON-OFF-ON. Bob |
OT How to size a diode?
|
OT How to size a diode?
On Mon, 24 Jan 2011 13:05:25 -0800 (PST), beecrofter
wrote: On Jan 24, 12:07*pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. *I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. *I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. *I am having a bit of trouble with selecting a diode. *I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. *The fans draw 20W each. *For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: *http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. *Recommendations please. *Once I complete this task I can get down to forming the sheetmetal. *Thanks Fan specs? If they're AC fans (as the 20W suggests) then forget it, just get a more appropriate switch eg. DPDT with center-off. Diodes will fry the fans. |
OT How to size a diode?
Bob Engelhardt wrote: Jon Danniken wrote: ? You don't neet a diode, you need a switch. Specifically, a DPDT Center-off ? switch. Often described in the online catalogs as a DPDT ON-OFF-ON. How will that turn on both fans at once? -- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated. |
OT How to size a diode?
Michael A. Terrell wrote:
Bob Engelhardt wrote: Jon Danniken wrote: ? You don't neet a diode, you need a switch. Specifically, a DPDT Center-off ? switch. Often described in the online catalogs as a DPDT ON-OFF-ON. How will that turn on both fans at once? In Jon's diagram, the "down" position turns both on. Bob |
OT How to size a diode?
Bob Engelhardt wrote:
Jon Danniken wrote: You don't neet a diode, you need a switch. Specifically, a DPDT Center-off switch. Often described in the online catalogs as a DPDT ON-OFF-ON. Aye, I also notice some of them say DPDT ON-NONE-ON. Jon |
OT How to size a diode?
On Mon, 24 Jan 2011 16:13:19 -0800, the renowned "Jon Danniken"
wrote: Bob Engelhardt wrote: Jon Danniken wrote: You don't neet a diode, you need a switch. Specifically, a DPDT Center-off switch. Often described in the online catalogs as a DPDT ON-OFF-ON. Aye, I also notice some of them say DPDT ON-NONE-ON. Jon It could also be done with a 2-pole 3-position (DP3T) slide switch, which could be wired to give off-lo-hi in that (or any other) order. Eg. http://www.allelectronics.com/make-a...-SWITCH/1.html 33 cents each. ;-) Too bad there's no easy way to mount it to a panel. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
OT How to size a diode?
On Jan 24, 7:13*pm, "Jon Danniken"
wrote: Bob Engelhardt wrote: .. Often described in the online catalogs as a DPDT ON-OFF-ON. Aye, I also notice some of them say DPDT ON-NONE-ON. Jon That's the two position version without a center OFF position. jsw |
OT How to size a diode?
On 1/24/2011 7:16 PM, Jim Wilkins wrote:
On Jan 24, 7:13 pm, "Jon Danniken" wrote: Bob Engelhardt wrote: .. Often described in the online catalogs as a DPDT ON-OFF-ON. Aye, I also notice some of them say DPDT ON-NONE-ON. Jon That's the two position version without a center OFF position. jsw This is exactly the switch function of an ordinary, every day 3-way lamp switch available at most any hardware store for a couple of bucks. Off-Low-Medium-High switch positions correspond to no motor, one motor, other motor and both motors. Carla It's all fun and games until she asks if you've ever seen "The Crying Game." |
OT How to size a diode?
On 1/24/2011 9:07 AM, wrote:
I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks is there any reason why you don't use a DPDT switch ? no diodes, works with AC or DC fans -- www.wbnoble.com |
OT How to size a diode?
Jim Wilkins wrote:
"Jon Danniken" wrote: Aye, I also notice some of them say DPDT ON-NONE-ON. That's the two position version without a center OFF position. Thanks Jim, now I know that. Jon |
OT How to size a diode?
On Mon, 24 Jan 2011 21:43:15 -0800, Carla Fong
wrote: On 1/24/2011 7:16 PM, Jim Wilkins wrote: On Jan 24, 7:13 pm, "Jon Danniken" wrote: Bob Engelhardt wrote: .. Often described in the online catalogs as a DPDT ON-OFF-ON. Aye, I also notice some of them say DPDT ON-NONE-ON. Jon That's the two position version without a center OFF position. jsw This is exactly the switch function of an ordinary, every day 3-way lamp switch available at most any hardware store for a couple of bucks. Off-Low-Medium-High switch positions correspond to no motor, one motor, other motor and both motors. Carla Good catch! |
OT How to size a diode?
On Jan 25, 12:43*am, Carla Fong wrote:
... This is exactly the switch function of an ordinary, every day 3-way lamp switch available at most any hardware store for a couple of bucks. Carla Yabbut those stores never have the right drill to mount those wall switches neatly in an aluminum panel. jsw, who has wired a motorcycle with duct-taped light switches to get it running. |
OT How to size a diode?
On Mon, 24 Jan 2011 21:59:20 -0800, Bill Noble
wrote: On 1/24/2011 9:07 AM, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks is there any reason why you don't use a DPDT switch ? no diodes, works with AC or DC fans He would need a dpdt center off switch. And exactly haw are you going to select ONE motor on one position, and 2 on the other with the motors in parallell? I can see if you tie the commons together, and tie both terninals of one side together, then feed the motors from the 2 terminals on one end of the switch - for 1 motor switch to the position that connects the common to the bridged terminals and the empty non-bridged terminal. For both to the position that connects the common to the occupied non-bridged and the bridged terminals. Other end of both motors tied together to the other (neuatral) line. Any other way? |
OT How to size a diode?
wrote:
He would need a dpdt center off switch. And exactly haw are you going to select ONE motor on one position, and 2 on the other with the motors in parallell? I can see if you tie the commons together, and tie both terninals of one side together, then feed the motors from the 2 terminals on one end of the switch - for 1 motor switch to the position that connects the common to the bridged terminals and the empty non-bridged terminal. For both to the position that connects the common to the occupied non-bridged and the bridged terminals. Other end of both motors tied together to the other (neuatral) line. Any other way? http://www.grumpyoldgeek.com/images/fan.jpg |
OT How to size a diode?
On Tue, 25 Jan 2011 10:37:58 -0800, Jim Stewart
wrote: wrote: He would need a dpdt center off switch. And exactly haw are you going to select ONE motor on one position, and 2 on the other with the motors in parallell? I can see if you tie the commons together, and tie both terninals of one side together, then feed the motors from the 2 terminals on one end of the switch - for 1 motor switch to the position that connects the common to the bridged terminals and the empty non-bridged terminal. For both to the position that connects the common to the occupied non-bridged and the bridged terminals. Other end of both motors tied together to the other (neuatral) line. Any other way? http://www.grumpyoldgeek.com/images/fan.jpg Basically what I said. You just moved the one jumper - has the same effect. |
OT How to size a diode?
OT, but worth mentioning.
Obama is on Fox on one TV and I'm recording Lynyrd Skynyrd singing God and Guns on PBS on the other one, jsw |
OT How to size a diode?
On 1/25/2011 10:07 AM, wrote:
On Mon, 24 Jan 2011 21:59:20 -0800, Bill Noble wrote: On 1/24/2011 9:07 AM, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. I have a 3 position switch (0, 1 , 2) so that I can run either one or two fans. I need a "check valve" (diode?) to prevent both of the fans from running when the switch is set for a single fan. I am having a bit of trouble with selecting a diode. I did a quick google search that leads me to believe that the diode needs to be specified based on reverse current to be blocked and the voltage. The fans draw 20W each. For such a cheap simple part, I wish to buy it at Radio Shack but looking at their web page: http://www.radioshack.com/family/ind...goryId=2032269 I am having difficulty trying to pick one - many of the diodes do not even show a spec sheet. Recommendations please. Once I complete this task I can get down to forming the sheetmetal. Thanks is there any reason why you don't use a DPDT switch ? no diodes, works with AC or DC fans He would need a dpdt center off switch. And exactly haw are you going to select ONE motor on one position, and 2 on the other with the motors in parallell? I can see if you tie the commons together, and tie both terninals of one side together, then feed the motors from the 2 terminals on one end of the switch - for 1 motor switch to the position that connects the common to the bridged terminals and the empty non-bridged terminal. For both to the position that connects the common to the occupied non-bridged and the bridged terminals. Other end of both motors tied together to the other (neuatral) line. Any other way? first, I don't recall a mention of off, but yes, a center off switch is the way to go. Wire white to both motors. Wire black to both center terminals of the switch. Connect motor 1 to pole 1 terminal 1. Connect motor 2 to pole 2, both terminals. How hard it this? -- www.wbnoble.com |
OT How to size a diode?
wrote:
On Tue, 25 Jan 2011 10:37:58 -0800, Jim wrote: wrote: He would need a dpdt center off switch. And exactly haw are you going to select ONE motor on one position, and 2 on the other with the motors in parallell? I can see if you tie the commons together, and tie both terninals of one side together, then feed the motors from the 2 terminals on one end of the switch - for 1 motor switch to the position that connects the common to the bridged terminals and the empty non-bridged terminal. For both to the position that connects the common to the occupied non-bridged and the bridged terminals. Other end of both motors tied together to the other (neuatral) line. Any other way? http://www.grumpyoldgeek.com/images/fan.jpg Basically what I said. You just moved the one jumper - has the same effect. Well, I read your paragraph 3 times and still couldn't understand what you were saying. Nor could I decide whether you were asking a real or rhetorical question. In any case, this sort of thing begs for a picture or drawing. |
OT How to size a diode?
On Jan 26, 11:57*am, Jim Stewart wrote:
. In any case, this sort of thing begs for a picture or drawing. Fixed pitch font. 0 is a switch terminal, / is a closed switch contact. Fan 1 is connected to two diagonally opposite terminals. Fan 1 only: fan1--0 0 / / power-0--0 fan2--0 0--fan1 Both fans: fan1--0 0 power-0--0 \ \ fan2--0 0--fan1 jsw |
OT How to size a diode?
Jim Wilkins wrote:
On Jan 26, 11:57 am, Jim wrote: . In any case, this sort of thing begs for a picture or drawing. That's why I linked to this picture when I replied: http://www.grumpyoldgeek.com/images/fan.jpg Fixed pitch font. 0 is a switch terminal, / is a closed switch contact. Fan 1 is connected to two diagonally opposite terminals. Fan 1 only: fan1--0 0 / / power-0--0 fan2--0 0--fan1 Both fans: fan1--0 0 power-0--0 \ \ fan2--0 0--fan1 jsw |
OT How to size a diode?
On Jan 24, 12:07*pm, wrote:
I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. * Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). Thanks again. |
OT How to size a diode?
|
OT How to size a diode?
On Wed, 26 Jan 2011 22:08:10 -0500, the renowned
wrote: On Wed, 26 Jan 2011 15:15:24 -0800 (PST), wrote: On Jan 24, 12:07*pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. * Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Diodes do not work as switches in AC circuits. You will need a proper switch to do the job on AC. The only way that comes to mind with AC would be to add an AC-coil SPST NO relay and I think a double pole switch will be easier and cheaper. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
OT How to size a diode?
On 1/26/2011 3:15 PM, wrote:
On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). Thanks again. I hope this doesn't sound snide, it's not intended to be. Please look at what a diode does. There are certainly diodes available to operate at AC mains voltages, and they are cheap. But what a diode does is not what you need done. There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. The question you asked shows a basic misunderstanding of AC current and how AC motors work. Reading even the most basic text will help you understand these responses. A switch that fits the existing hole will not be a problem. -- www.wbnoble.com |
OT How to size a diode?
On Wed, 26 Jan 2011 21:32:03 -0800, Bill Noble
wrote: On 1/26/2011 3:15 PM, wrote: On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). Thanks again. I hope this doesn't sound snide, it's not intended to be. Please look at what a diode does. There are certainly diodes available to operate at AC mains voltages, and they are cheap. But what a diode does is not what you need done. There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. The question you asked shows a basic misunderstanding of AC current and how AC motors work. Reading even the most basic text will help you understand these responses. A switch that fits the existing hole will not be a problem. If he was running DC fans, a diode does EXACTLY what he wants to do - but a diode cannot do that job on AC, no matter what kind of diode you manage to get your hands on. |
OT How to size a diode?
On Jan 27, 6:28*pm, wrote:
On Wed, 26 Jan 2011 21:32:03 -0800, Bill Noble wrote: On 1/26/2011 3:15 PM, wrote: On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. *The fans are 120v. *I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. *I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. *I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). *Thanks again. I hope this doesn't sound snide, it's not intended to be. *Please look at what a diode does. *There are certainly diodes available to operate at AC mains voltages, and they are cheap. *But what a diode does is not what you need done. *There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. *The question you asked shows a basic misunderstanding of AC current and how AC motors work. *Reading even the most basic text will help you understand these responses. *A switch that fits the existing hole will not be a problem. *If he was running DC fans, a diode does EXACTLY what he wants to do - but a diode cannot do that job on AC, no matter what kind of diode you manage to get your hands on. This Whole Thread is a massive.. Who Cares! The OP was a Hit and run, and hasn't been back anyway. But a lot of good discussion, and solutions, and lateral and forward thinking. |
OT How to size a diode?
Cross-Slide wrote: On Jan 27, 6:28 pm, wrote: On Wed, 26 Jan 2011 21:32:03 -0800, Bill Noble wrote: On 1/26/2011 3:15 PM, wrote: On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). Thanks again. I hope this doesn't sound snide, it's not intended to be. Please look at what a diode does. There are certainly diodes available to operate at AC mains voltages, and they are cheap. But what a diode does is not what you need done. There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. The question you asked shows a basic misunderstanding of AC current and how AC motors work. Reading even the most basic text will help you understand these responses. A switch that fits the existing hole will not be a problem. If he was running DC fans, a diode does EXACTLY what he wants to do - but a diode cannot do that job on AC, no matter what kind of diode you manage to get your hands on. This Whole Thread is a massive.. Who Cares! The OP was a Hit and run, and hasn't been back anyway. Yes, he was. In fact, the orginal message and his reply are quoted in your message. But a lot of good discussion, and solutions, and lateral and forward thinking. -- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated. |
OT How to size a diode?
On Jan 27, 8:28*pm, "Michael A. Terrell"
wrote: Cross-Slide wrote: On Jan 27, 6:28 pm, wrote: On Wed, 26 Jan 2011 21:32:03 -0800, Bill Noble wrote: On 1/26/2011 3:15 PM, wrote: On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. *The fans are 120v. *I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. *I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. *I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). *Thanks again. I hope this doesn't sound snide, it's not intended to be. *Please look at what a diode does. *There are certainly diodes available to operate at AC mains voltages, and they are cheap. *But what a diode does is not what you need done. *There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. *The question you asked shows a basic misunderstanding of AC current and how AC motors work. *Reading even the most basic text will help you understand these responses. *A switch that fits the existing hole will not be a problem. *If he was running DC fans, a diode does EXACTLY what he wants to do - but a diode cannot do that job on AC, no matter what kind of diode you manage to get your hands on. This Whole Thread is a massive.. Who Cares! The OP was a Hit and run, and hasn't been back anyway. * *Yes, he was. *In fact, the orginal message and his reply are quoted in your message. I stand corrected! |
OT How to size a diode?
Cross-Slide wrote: On Jan 27, 8:28 pm, "Michael A. Terrell" wrote: Cross-Slide wrote: On Jan 27, 6:28 pm, wrote: On Wed, 26 Jan 2011 21:32:03 -0800, Bill Noble wrote: On 1/26/2011 3:15 PM, wrote: On Jan 24, 12:07 pm, wrote: I am fabricating a small box that will house a couple of "muffin" fans to direct air behind a fireplace insert. Thanks to all of you for the responses. The fans are 120v. I just assumed that there were diodes available for line voltage - they make hydraulic check valves for all sorts of pressures. Looks like I need to find a different switch. I bought the switch a couple of years ago for this (future) project and suddenly when I got the meter out to check the terminals, I realised that both fans were going to run on both fan settings. I'll look into the switches mentioned and see how I can package them (the hole is already made - duh!). Thanks again. I hope this doesn't sound snide, it's not intended to be. Please look at what a diode does. There are certainly diodes available to operate at AC mains voltages, and they are cheap. But what a diode does is not what you need done. There are some very simple, easy to read books and articles about basic electricity, that explain AC and DC and some essential concepts - one of my favorite was a military training manual which is probably available in PDF. The question you asked shows a basic misunderstanding of AC current and how AC motors work. Reading even the most basic text will help you understand these responses. A switch that fits the existing hole will not be a problem. If he was running DC fans, a diode does EXACTLY what he wants to do - but a diode cannot do that job on AC, no matter what kind of diode you manage to get your hands on. This Whole Thread is a massive.. Who Cares! The OP was a Hit and run, and hasn't been back anyway. Yes, he was. In fact, the orginal message and his reply are quoted in your message. I stand corrected! Then sit down! You're blocking everyone's view. ;-) -- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated. |
OT How to size a diode?
Coooool way coooool , switching transistors , pulll down the fan , to ground ... no diodes .. BTW create stuf @ googlegroups . com no noise , its moderated .. If its a technical problem its OK in this news group ,, but i dont know how to access my news group , help ! give me your email adress , ill add if i knew how .. yes , i can add addresses , but i can access the account , cant find it nor figure it , yet im the creator ! I promise a huge database of tech stuff . |
OT How to size a diode?
for got to post the easier way . buy Home Depot curly compact flour bulbs , transistors , diodes high voltage caps inductors , worth far more than the $1 I got 1000 the hard way , sawing off the base and cutting the PCB and re wiring the 13003 / BLD123a high voltage NPN's parallel , for 300 watts from a 23watt CFL . News Groups ? High tech moderated createstuf @ Googlegroups . com I need help to access it , and yet i created it , give help pls |
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