Re: [MBZ] OT: Source for electronic rectifier control
It just occurred to me that the everything I needed should have been in the APC 650 UPSs I recently pitched. Including the heat sink. too bad I can't modify one of them to work. The hoarders lament: As soon as I DO pitch something, I soon will need it. Some corollary to Murphy in there... If you keep it you won't need it, if you pitch it, you will soon have a need for it. On Mon, 9 Apr 2012 08:15:24 -0500 Dieselhead <126die...@gmail.com> wrote: 50 A 1000 Volt rated should work then. http://www.ebay.com/itm/110735275271?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649#ht_1380wt_702 ebay Item number: 110735275271 Yes, that is what I was describing. I can mount an old computer heat sink to the top of the case. It will have to be a fairly big heatsink (or else have a fan for forced air cooling). You want something that has a thermal resistance of 1 deg.C./Watt or less. Now if I can find a couple of panel voltmeters and a DC ammeter, I should have a linear rectifier as good as the one in the $8000 kit. Only yours won't be regulated. If your line voltage changes, your DC out will change, too. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Mon, 9 Apr 2012 08:15:24 -0500 Dieselhead <126die...@gmail.com> wrote: > 50 A 1000 Volt rated should work then. > http://www.ebay.com/itm/110735275271?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649#ht_1380wt_702 > > ebay Item number: 110735275271 Yes, that is what I was describing. > I can mount an old computer heat sink to the top of the case. It will have to be a fairly big heatsink (or else have a fan for forced air cooling). You want something that has a thermal resistance of 1 deg.C./Watt or less. > Now if I can find a couple of panel voltmeters and a DC ammeter, I > should have a linear rectifier as good as the one in the $8000 kit. Only yours won't be regulated. If your line voltage changes, your DC out will change, too. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
50 A 1000 Volt rated should work then. http://www.ebay.com/itm/110735275271?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649#ht_1380wt_702 ebay Item number: 110735275271 I can mount an old computer heat sink to the top of the case. Now if I can find a couple of panel voltmeters and a DC ammeter, I should have a linear rectifier as good as the one in the $8000 kit. On Sun, 8 Apr 2012 22:36:10 -0500 Dieselhead <126die...@gmail.com> wrote: What would the specs of the diodes need to be to pass up to 25 amps@ up to 120 V? Each rated for 25 Amp or more? It just seemed easier to buy a rectifier than to build one. But to get 25 amp, I may need to build. Get a pre-packaged bridge rectifier. They usually are square, have four terminals, and have a metal pad with a hole through it for bolting to a heat sink. You should get a bridge with at least a 400 V rating (the capacitor will store 120*sqrt(2) DC and the reversed diode will see the line go opposite polarity, for a total of 2*120*sqrt(2) ). Buy, don't build. If you'd like I can search for a source of the right kind of thing tomorrow. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Sun, 8 Apr 2012 22:36:10 -0500 Dieselhead <126die...@gmail.com> wrote: > What would the specs of the diodes need to be to pass up to 25 amps@ > up to 120 V? Each rated for 25 Amp or more? > > It just seemed easier to buy a rectifier than to build one. But to > get 25 amp, I may need to build. Get a pre-packaged bridge rectifier. They usually are square, have four terminals, and have a metal pad with a hole through it for bolting to a heat sink. You should get a bridge with at least a 400 V rating (the capacitor will store 120*sqrt(2) DC and the reversed diode will see the line go opposite polarity, for a total of 2*120*sqrt(2) ). Buy, don't build. If you'd like I can search for a source of the right kind of thing tomorrow. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
> Dieselhead wrote: > What would the specs of the diodes need to be to pass up to 25 > amps@ up to 120 V? Each rated for 25 Amp or more? Each diode carries the full current, but only half the time. So if it is going to have 25 A continuous through it, I would look for a 30-35 A diode rated for at least 200 V (120 V-RMS is 170 V peak). > It just seemed easier to buy a rectifier than to build one. > But to get 25 amp, I may need to build. It's easy to build. Four diodes is all it takes. Here is a link to a diagram for a bridge rectifier. https://en.wikipedia.org/wiki/File:Diode_bridge_smoothing.svg That diagram is the article: https://en.wikipedia.org/wiki/Diode_bridge The advantage to a pre-built bridge is it's easier to wire. And occasionally it's cheaper. As Craig said, there will be a fair amount of heat from these diodes, so be sure to mount them in a way to dissipate that heat. -- Philip ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
What would the specs of the diodes need to be to pass up to 25 amps@ up to 120 V? Each rated for 25 Amp or more? It just seemed easier to buy a rectifier than to build one. But to get 25 amp, I may need to build. Thanks Philip and Craig for helping me out with this demo unit. You can build your own bridge out of four individual diodes. ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
Good idea, but it might take some of the "fun" out of the demo! If it were me, I would wire a high value resistor across the capacitor to dissipate the change so that after 10 or 15 minutes the "hairy" is gone from your BHC. -- Philip ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
> Dieselhead wrote: I found 50 Amp bridge rectifiers. I figured I could use 2 in parallel to be able to pass 50 to 70 amps. Nope. Not unless you have two transformers. Each diode will have a _slightly_ different turn-on voltage, so the one that's a touch lower will hog all the current and the other one will not do much of anything. You can build your own bridge out of four individual diodes. So wire the variac to the rectifiers, (AC side) then hang the BHC across the DC side of the rectifiers. Is that right? (DC to the iron cathode and anode.) If it were me, I would wire a high value resistor across the capacitor to dissipate the change so that after 10 or 15 minutes the "hairy" is gone from your BHC. -- Philip ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Sun, 8 Apr 2012 12:47:27 -0500 Fmiser wrote: > If it were me, I would wire a high value resistor across the > capacitor to dissipate the change so that after 10 or 15 minutes > the "hairy" is gone from your BHC. This is a good idea. Each capacitor will hold about 48 Joules of energy when the variac outputs 120 VAC. You will want to check things with a voltmeter before you handle the connections after a run. If you run less than 120 VDC output, a 25 W lightbulb will make a dandy bleeder resistor. Just wire one or two across the capacitor bank. One will give you a time constant of 6 seconds; two will give a time constant of 3 seconds. Five time constants (15 - 30 s) will drop the voltage across the capacitor bank to close to zero. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Sun, 8 Apr 2012 08:38:36 -0500 Dieselhead <126die...@gmail.com> wrote: > Sorry! It is 450V rated That's quite enough. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
> Dieselhead wrote: > I found 50 Amp bridge rectifiers. I figured I could use 2 in > parallel to be able to pass 50 to 70 amps. Nope. Not unless you have two transformers. Each diode will have a _slightly_ different turn-on voltage, so the one that's a touch lower will hog all the current and the other one will not do much of anything. You can build your own bridge out of four individual diodes. > So wire the variac to the rectifiers, (AC side) then hang the > BHC across the DC side of the rectifiers. Is that right? > (DC to the iron cathode and anode.) If it were me, I would wire a high value resistor across the capacitor to dissipate the change so that after 10 or 15 minutes the "hairy" is gone from your BHC. -- Philip ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
Sorry! It is 450V rated On Sat, 7 Apr 2012 23:29:06 -0500 Dieselhead <126die...@gmail.com> wrote: Does 3500 Microfarad count as BHC? Yes. WHAT VOLTAGE RATING? I can buy one on fleabay for $10 or 3 for $20. I was thinking maybe buying 3 and using as many as needed. I found 50 Amp bridge rectifiers. I figured I could use 2 in parallel to be able to pass 50 to 70 amps. Paralleling rectifiers can be tricky and is not recommended (you can easily get thermal run-away, where one bridge is taking all the current). The original article said 70 V and 30 A. I'd use just one. You will need to make sure the rectifier has a good heat sink -- at 30 A, you will be dissipating roughly 60 W in the bridge and want to keep the bridge's temperature below 70 deg.C. or so. So wire the variac to the rectifiers, (AC side) then hang the BHC across the DC side of the rectifiers. Is that right?(DC to the iron cathode and anode.) Yes, that is correct. Just remember both output leads will be hot with respect to ground. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Sat, 7 Apr 2012 23:29:06 -0500 Dieselhead <126die...@gmail.com> wrote: > > Does 3500 Microfarad count as BHC? Yes. WHAT VOLTAGE RATING? > I can buy one on fleabay for $10 or 3 for $20. I was thinking maybe > buying 3 and using as many as needed. > I found 50 Amp bridge rectifiers. I figured I could use 2 in > parallel to be able to pass 50 to 70 amps. Paralleling rectifiers can be tricky and is not recommended (you can easily get thermal run-away, where one bridge is taking all the current). The original article said 70 V and 30 A. I'd use just one. You will need to make sure the rectifier has a good heat sink -- at 30 A, you will be dissipating roughly 60 W in the bridge and want to keep the bridge's temperature below 70 deg.C. or so. > So wire the variac to the rectifiers, (AC side) then hang the BHC > across the DC side of the rectifiers. Is that right?(DC to the > iron cathode and anode.) Yes, that is correct. Just remember both output leads will be hot with respect to ground. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
If you are making a simple variable DC power supply, yes. Dan Dieselhead <126die...@gmail.com> wrote: > >Does 3500 Microfarad count as BHC? > >I can buy one on fleabay for $10 or 3 for $20. I was thinking maybe >buying 3 and using as many as needed. > >I found 50 Amp bridge rectifiers. I figured I could use 2 in >parallel to be able to pass 50 to 70 amps. > >So wire the variac to the rectifiers, (AC side) then hang the BHC >across the DC side of the rectifiers. Is that right?(DC to the >iron cathode and anode.) > >___ >http://www.okiebenz.com >For new and used parts go to www.okiebenz.com >To search list archives http://www.okiebenz.com/archive/ > >To Unsubscribe or change delivery options go to: >http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
Does 3500 Microfarad count as BHC? I can buy one on fleabay for $10 or 3 for $20. I was thinking maybe buying 3 and using as many as needed. I found 50 Amp bridge rectifiers. I figured I could use 2 in parallel to be able to pass 50 to 70 amps. So wire the variac to the rectifiers, (AC side) then hang the BHC across the DC side of the rectifiers. Is that right?(DC to the iron cathode and anode.) ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Fri, 6 Apr 2012 22:31:04 -0500 Dieselhead <126die...@gmail.com> wrote: > The 1 got cut off the front. Try this: > 144.206.159.178/ft/1092/72646/1241702.pdf Yup, that works much better. > The DC power supply is described in 2.1 on page 4066: >From that page, the appropriate description is: > The laboratory test system consisted of an electrocoagulator unit with > a 500W (70 V/30 A) DC power supply (Wayne Kerr Electronics Ltd., Model > AP7030), Besides the fact that 70 V x 30 A is not 500 W, there doesn't seem to be much required of the power supply. The variac, bridge rectifier, and BHC will do the job just fine. Just don't forget that both output leads of the setup will be hot with respect to ground. I would use iron electrodes, not aluminum, since aluminum has been implicated in Alzheimers. (And then there is table salt that has aluminum in it and baking powder that has aluminum in it, but don't get me started on those.) Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
The 1 got cut off the front. Try this: 144.206.159.178/ft/1092/72646/1241702.pdf On Fri, 6 Apr 2012 21:38:08 -0500 Dieselhead <126die...@gmail.com> wrote: I am not sure of the specs needed. I have been trying to find out. The application is a bench scale electrocoagulation unit. Sounds like it might prefer fairly good quality DC. These are too small: www.testequipmentconnection.com/tecspecs/Agilent-HP_E3610A.PDF Here is a paper that explains the process. The DC power supply is described in 2.1 on page 4066: 44.206.159.178/ft/1092/72646/1241702.pdf That URL doesn't load for me. Perhaps you can copy and paste? TIA for any and all assistance I'll try ... Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Fri, 6 Apr 2012 21:38:08 -0500 Dieselhead <126die...@gmail.com> wrote: > I am not sure of the specs needed. I have been trying to find out. > The application is a bench scale electrocoagulation unit. Sounds like it might prefer fairly good quality DC. > These are too small: > www.testequipmentconnection.com/tecspecs/Agilent-HP_E3610A.PDF > > Here is a paper that explains the process. The DC power supply is > described in 2.1 on page 4066: > 44.206.159.178/ft/1092/72646/1241702.pdf That URL doesn't load for me. Perhaps you can copy and paste? > TIA for any and all assistance I'll try ... Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
I am not sure of the specs needed. I have been trying to find out. The application is a bench scale electrocoagulation unit. These are too small: www.testequipmentconnection.com/tecspecs/Agilent-HP_E3610A.PDF Here is a paper that explains the process. The DC power supply is described in 2.1 on page 4066: 44.206.159.178/ft/1092/72646/1241702.pdf TIA for any and all assistance On Tue, 27 Mar 2012 22:27:34 -0500 Dieselhead <126die...@gmail.com> wrote: Alles: I need a source for a 25 Amp 110 volt AC (input) variable linear DC voltage control. A listing of components to build one would be ok too. Could I build such a thing out of one of the variacs I have with a full wave bridge rectifier? What else might be needed for this approach? It depends on what quality of DC power you need and how you are going to use it. If you don't mind the DC not being grounded, are careful with isolation of the output to ground, and don't want accurate regulation, all you need is a full wave bridge rectifier and a big hairy capacitor, BHC (tm). You will need to be careful you don't exceed the voltage rating of the capacitor. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Sat, 31 Mar 2012 10:35:01 -0500 OK Don wrote: > I can vouch for that! My first transmitter's power amp was fed 500 > volts. All I had in the junk box was a pair 450 volt capacitors, so I > figured it would have suffienct of a margin of error built in. Usually, you want to derate the capacitor and not run it at its voltage rating. For commercial equipment, you want to run it at 80% of its rating. For military, 50%. > It worked for about six months, then one cap went bang - blew the bottom > out and released a LOT of smoke. Once again proving that electronics really runs on smoke. If you let the smoke out, the electronics stops working. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
> > You will need to be careful you don't exceed the voltage rating of the > capacitor. > > > Craig I can vouch for that! My first transmitter's power amp was fed 500 volts. All I had in the junk box was a pair 450 volt capacitors, so I figured it would have suffienct of a margin of error built in. It worked for about six months, then one cap went bang - blew the bottom out and released a LOT of smoke. Needless to say, I wasn't able to complete that conversation (CW, 80 meters). -- OK Don KD5NRO 2001 ML320 1992 300D 2.5T 1990 300D 2.5T 1997 Plymouth Grand Voyager ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT: Source for electronic rectifier control
On Tue, 27 Mar 2012 22:27:34 -0500 Dieselhead <126die...@gmail.com> wrote: > Alles: > > I need a source for a 25 Amp 110 volt AC (input) variable linear DC > voltage control. > > A listing of components to build one would be ok too. > > Could I build such a thing out of one of the variacs I have with a > full wave bridge rectifier? What else might be needed for this > approach? It depends on what quality of DC power you need and how you are going to use it. If you don't mind the DC not being grounded, are careful with isolation of the output to ground, and don't want accurate regulation, all you need is a full wave bridge rectifier and a big hairy capacitor, BHC (tm). You will need to be careful you don't exceed the voltage rating of the capacitor. Craig ___ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com