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Re: 3-500Z socket.... Johnson vs Eimac
On Nov 13, 2006, at 2:30 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:The Eimac spec sheet says 0.82" at sea level.requires a high-pressure centrifugal blower, and Ham amps used an And that's for 500/1000 w CCSOpinions count way less than manometer measurements. Heck......The nickels are glued down about 5" apart.corners along one edge is light enough to rise automatically withA square of varnished cardboard with two nickels glued to theflap that hinges up to let the air out. It just doesn't look as They are correct -- it's called Stephan's Law and the power radiatedred radiation?RICH SEZ... So objects that glow red-orange do not exhibit infra-### here's the interesting bit. Eimac states the glass tubescool by infared radiation.... well my natural gas fireplace puts is a function of the object's Temp raised to the 4th power. I can put my handsYou would have done somewhat better at this point had you put your hands on the mouse and clicked Send. . on theThe SB-220 has a ¡Ö600W HV transformer. Hello! cheers, Jim .R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: "Father Measures"
On Nov 13, 2006, at 3:53 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:Hardly, Jim. I know too much about history to ever join any organized religion.make a good priest. Maybe they were joking?... cheers R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: Inrush filament current protection
On Nov 13, 2006, at 4:48 AM, Robert B. Bonner wrote:
Jim,Is not 240v standard in the United States? residential circuits are two wire, the third wire is a GROUNDIf they connect together in the breaker box, is this really safe? ... ... R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: Inrush filament current protection
Robert B. Bonner
Jim,
toggle quoted message
Show quoted text
I know several years ago a friend sent me some copies of the posts on AMPS when I wasn't a member. There were comments rather heated regarding POWER SERVICES and AC wiring to amps. I will end that quickly here as I won't tolerate incorrect info to pass me by. You are a smart guy, very knowledgeable and have some good experiences but let's define power services / wiring correctly to avoid any errors. You and I are saying the same things but differently. Separated by a common language. I worked three years as an electrician... Knew my business. Standard 220V residential circuits are two wire, the third wire is a GROUND (Green) not a neutral. Most dryers are 2 wires plus ground here. You wire your Ameritron its two wires plus a ground. If you have a 4 wire 220 circuit including Power Cord and a 4 conductor plug... Two blacks a white and a green. You have 220 plus neutral. This will give you 220V via two 120 circuits and a ground. This is a direct extension of your panel service. Most residential 220V items don't use 4 wire. Not to be confused with 3 Phase which is all different colors / uses. In residential services in the states we tie the NEUTRALS and the GROUND Buss together in the main panels, however that NEVER by definition makes them "the same thing". Neutral is Neutral and Ground is always Ground. Try switching them in a ground fault circuit and the breaker will blow. The green wire should NEVER conduct current. SO if you are utilizing a 120 volt transformer somewhere in your homebrew for a control circuit or filament you should also be utilizing either a 220-120V step down transformer in your construction or a 4 wire 220 circuit to meet code... This is why large commercial HF power generators like the Henrys (even the 8K) have 220-120 step down transformers inside them. Others use 220V filament transformers not 120 to meet the electrical code... Why don't they use all 220 transformers? New regs requiring both legs to blow when one goes. They put gangbared main breakers on the gear, but utilize 120 volt fuses for all the other small circuits to save money. The 220-120 step down is cheaper to fuse than dual breakers on all circuits. Now will it work your way? That is 120V circuits wired to one side of the line? YES... Does it meet code? No... FYI The base Alpha 77 wasn't UL approved. It had a hot ground wire. There was a higher cost version that had a step down transformer in it if you REQUIRED a two wire circuit. That's mentioned right in their manual. You are correct on all the other points. The separate CB's wouldn't fly today without a tied together gangbar to kill both sides of the AC line. A Grandfathered in system does not make it a good system. :-( That's what I was referring to as CHEATING The System. Breaking the Electrical Code. Since we are basically saying the same thing differently... We have no argument. BOB DD -----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of pentalab Sent: Monday, November 13, 2006 3:41 AM To: ham_amplifiers@... Subject: [ham_amplifiers] Re: Inrush filament current protection --- In ham_amplifiers@..., "Robert B. Bonner" <rbonner@...> wrote: RIGHT NOW that had me thinking the same thing. ### huh ? AS long as you have a relay/contactor/ ckt breaker that opens OFF BOTH sides of the 240v line... anything beyond that is a moot point...and legal. BEWARE... if using fuses on the primary.... they HAVE to be 240 V rated... NOT 120 V rated. Here's why. IF only one fuse in one leg of the primary blew open... and the 2nd fuse in the other leg was intact....you could end up in a situation where 120 v is fed to one side of the plate xfmr primary.... where it will simply pass throught the typ .08 ohm dc resistance primary... then back to the OUTPUT side of the blown fuse.[call this leg #2] Meanwhile... on the INPUT side of the blown fuse.... you still have 120 V [coming from leg #1.] The potential difference across the blown fuse in leg #1 will be ...240 V. IE: with EITHER fuse blown [but only one], you will have 240 v across an open fuse.... so DON'T use 120 V rated fuses in either leg of a 240 v LINE. ### ALSO BEWARE.... some amps like the L4B... use two SEPARATE circuit breaker's... one per hot leg... and NO tie bar between em. These are usually the type that resemble a 3agc fuse holder.When these type of breakers open up... they extend outwards. wire plus neutral. ### partially agreed. ALL wire now comes with a bare or insulated grnd...whether u want it or not. The grnd is NEVER considered any more in the wire count. So, you either ask/order 2 conductor wire.... OR 3 conductor wire. 2 x conductor wire comes with a grnd... so total wires = 3. 3 x conductor wire also comes with a grnd... so total wires = 4. IE: you ask fo 3 x wire XXX ga.... u get a total of 4 x conductor's. practices you could get by with only 1 resistor in the step start. #### The electrical code will state on a 240 v circuit you will require a TWO pole breaker..and/or a TWO pole relay/contactor... to open off BOTH sides of the line. After that.. they could care less if u install a 12.5 ohm resistor in EACH hot leg... or a 25 ohm resistor in just ONE hot leg. Putting a resistor in both legs is a waste of effort. It's total LOOP resistance we are concerned with here. like a filament transformer that runs on 110 you would want to have 2 resistors in the step start. ### Agreed. BUT.... on an amp like the L4B.. and 99% of em... that have a SEPARATE fil xfmr.... the fil xfmr will ALWAYS have it's own dual 120 v primary's.... which can be wired in parallel for 120v... or in series for 240 V. The only exception to this.. would be if in a condo with 208/120V wiring per suite. You can then run 208 V into the plate xfmr [wired for 240V.. so u end up with slightly less plate V].... and run 120 V to the fil xfmr [wired for 120V... so fil gets correct V] ### IF, indeed one had a fil xfmr that ONLY ran on 120v.... then, you would have to ensure that the hot leg feeding the fil xfmr.. came from the SAME side of the 240 v line.... as your single step start resistor.... so when step started... you step start BOTH the HV supply AND the fil xfmr... at the same time...from the same source. ### No you wouldn't. That could only happen if one side of the 120V fil xfmr [or any other 120 v device] was tied directly to the chassis.. instead of the neutral. That isn't going to happen.. since it's not allowed... would violate every electrical code in North America. On a similar note... you NEVER bond the neutral to the chassis.... that also violates every electrical code in NA. The ONLY thing bonded to the chassis is the grnd wire. With any shorts from either side of line to chassis... the grnd wire handles the full fault current. ### On circuits which require a huge 240 V load... like a HV supply... but only a tiny load for the 120 V load... like say a 120 V blower... some tiny xfmr's for a T/R supply, etc... then it would be ok to use a smaller neutral.... as long as the neutral could handle the entire fault current... IF a line to neutral short occured. EG: 2 ga wire for each hot leg... and a 100 A main breaker in panel... but only 6 ga wire for the neutral.... and also 6 ga wire for the grnd. ### You see that in the Henry 8 k manual. They do that to run the 120 v Dayton blower. In EU/UK... they don't use a 3 wire 220 v line. They only have 2 x wires from the pole pig... with 220 v across em. One side of the line is bonded to earth ground... so one leg is hot... the other leg is valled neutral. That way, they only have to fuse the ONE hot leg... and any switches, relays, etc, are only required to be single pole types... for the one hot leg. As per the 8K... when you look up the Dayton blower part number they spec in their parts list in their manual.... and cross reference it to the Dayton blowers on Grainger's website... turns out it's the 230 V version of the same blower... and in fact, the 240/120 V step down xfmr shown in the schematic and also the picture drawings.... doesn't exist. ## Notice on 240 V clothes dryers... they always include a neutral... to run the 120 V blower. Seems stupid to me. They shoulda just used a 240v blower... and could have eliminated the requirement for a neutral..... just like a 240 v hot water tank.... none of which have a neutral... since the heating els run on 240 V only. Another option is 4 wire circuitry where you have 220 plus neutral and ground. What a pain with the outlets etc...### what's the problem with the outlets ??? A 30 A dryer outlet comes with 2 x hots, one neutral... one gound. A 40 A stove is exactly the same thing. Ditto with 20 A circuits. brewing does it really matter? NAW it will turn on and work. ### with HB HV supplies... you don't need an outlet. You just hardwire the 2 ga wire directly to the line side input of the front or rear panel mounted breaker. OR hardwire the 2 ga wire directly to the jumbo contactor input..... either way... you still have the breaker in the main panel that feeds this mess. You can buy 75/100/150/200 A outlets... cost a small fortune. You don't need em.... just hardwire the big wire in..... and when working on the amp.... kill the breaker in the main panel. IF the HV supply/amp needs to be rolled over to the bench... just disconnect the 4x wires at the HV/amp end. prettier, double pole relay, pair of resistors, double pole relay all in line. Nice pretty yellow adjustable time delay relay. ### Here's what I do. I use 25 ohms in one leg only... and only one contactor to short out the resistor. The kicker is.. I use a pair of paralled 50 ohm resistor's to make up the 25 ohms ! If one resistor ever opened up... the 2nd one [albeit 50 ohms] is still in the circiut. That way... I can never shunt an open single resistor with the step start contactor... and slam a huge load on the diodes.... IE: no step start at all... which would be a disaster with 100-200 uf C input filter. These large metal finned resistor's you see made by DALE and other's, works perfectly for the step start R. Just bolt it to metal chassis anywhere. Cuz of our magnetizing current.... I use a min of a 100w - 200 W rated units... EACH. You will have the entire 240 V dumped across em when you 1st hit the switch. When everything settles down... I still have 2 A of magnetizing current flowing through em..[100/200 w]... then they get shunted. ## I also use the yellow /white adjustable Time delay relay. The TD relays are all DPDT 10 A contacts.... which are used to activate the coil of the step start contactor. The big step start contactor has loads of AUX contacts... which are wired to the amp key line.... ditto with main incoming contactor.... so you can't key the amp unless all the contactor's are actually operated. We use loads of 120 v neons as well.. status lamps... to tell us instantly, where a problem is.. works slick.. if and when it comes time to trbl shoot anything. A row of 3agc fuses [and more neons on the output sides of the fuses] are the various feeds for the blower, TD relays, small xfmr's for T/R relays, contactor's etc. ### On the big stuff.... we use a separate Time delay for the fil xfmr... which has it's own step start resistor/ variac, etc. The fil TD is set for 8-10 seconds.... the HV delay is set for 15- 25 seconds. The blower over run TD is set for 15 mins. -also have an airflow vane/ switch, retrofitted inside the blower. Contacts of the airflow switch are wired to the coil of a small relay.... whose contacts open off the 240 V to the fil xfmr. The last thing you want is no air to a tube... esp when it's 30' away... in another room. The slick thing about this setup is... IF the commercial AC power goes off.... everything shuts down. When the power comes back on.... everything just goes through it's normal step start sequence etc. You can't key the amp... until it's all finished. Later... Jim VE7RF [mailto:ham_amplifiers@...] On Behalf Of Garry Drummondresistor in both sides of the 240 volt line for inrush current protection orwould a single resistor of adequate size in one leg do the job? I amspeaking of the typical amplifier running a pair of 3-500's. Yahoo! Groups Links |
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Re: "Father Measures"
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
make a good priest. Maybe they were joking?... ### I can just see it now.... "Father Measures" ... up on the mound.. preaching a fire and brimstone lecture about..."parasitic hell"....to us globar heathen's, with the ARRL bible in one hand.... and a wouf hong ...made of solid Nichrome in the other hand. Quick... run for your lives ! The sky is falling. later... Jim VE7RF R L Measures, AG6K, 805.386.3734 |
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Results of removing grid fuse + cathode fuse
pentalab
OK, here's the deal.
I had my buddy with the 3x6 remove the fast 750 ma grid fuse from the 3agc fuse holder... then try and apply 800w of drive. INPUT SWR on the big amp goes sky high.... and then the IPA [87-A] kicks itself offline..... leaving just the MK-V... which then see's the same sky high swr.... and the yaesu MK-V of course throttles back to zero watts output. .... good. Grid fuse was re-installed. Next up... the 3A 3agc cathode fuse was removed. Again, 800w of drive applied. Exact same results..... sky high input SWR... etc. Note... the grid fuse results ONLY happen, if their is NOTHING placed across the grid fuse holder.[no path for DC grid current, amp can't be driven]. Originally we had a 100 K 3 w mof reistor in parallel with the grid fuse holder. Upon grid fuse removal... and drive applied.... we were down to 2kw out... instead of the usual 12 kw. Input swr went from 0 watts reflected, to 60 w reflected [800 w forward = 8 % reflected.=low swr] We could also pull grid current.... but a LOT less. What was happening is this. The V drop across the 100 k mof resistor [with grid fuse removed] was directly in parallel with the reverse connected 6 A diodes... wired between chassis and B- The V drop across the 100 k resistor turned on the diode.... and grid current would flow via this new...alternate path. Meanwhile, the V drop across the 100 K resistor was still being applied to the cathode... and heavily biasing the amp into class C. So, the 100k resistor across the grid fuse ISNT'T needed.... don't install it. Rich suggested a MOV in parallel with the grid fuse holder. That's not needed either. The RVS connected diodes between chassis and B- are STILL in parallel with the grid fuse holder. Later... Jim VE7RF |
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Re: Can a ..power factor correction cap be used on the input of a Plate Xfmr ??
pentalab
--- In ham_amplifiers@..., "craxd" <craxd@...> wrote:
### Yes.. pse do. It would be much appreciated as I have hit a dead end here. That value though seems way to much at 35 uF for this. Placed across the primary leads, it will start looking like a short or a leak if big enough. That's why your seeing an increased current. The cap is causingmore current to be drawn or mag I + cap I. #### My conclusion is... since pri current went from 1.8 A to 2.3A.... Cap current added another .5 A All transformers have magnetizing current which is low compared to their output power.the higher the flux density its ran at, the higher it will be.### agreed. Point here is that we spend most of the time on RX... and 2 A of magnetizing current = 480Va. Nothing we can do about it. As far as power factor goes... that might be something we can do something about. IF the correct size pwr factor cap can be installed.... and the cap still draws current on RX.... then it would be easy to switch out the cap on RX... with a vac relay. For this type transformer service, the power factor should be about 0.95 or so. ### I'd say the power factor on a large C input filter would be at least .9 EG: u want to suck 900 w.... u need 1000 va. .9 x 1000 = 900w. Also 1000va/900w = 1.11 or 11% more primary current required... due to power factor. Then you have to factor in core losses.. another 10 %. So to convert DC input WATTS to PRIMARY VA.... u gotta multiply dc input x 1.22 I measured it... that's excatly what I get on a hypersil C core... like atyp pole pig... or a Dahl product. On My 80 lb hammond plate xfmrs [high reactance EI types... made for choke input.... but configured as a C input filter] you gotta multiply dc input watts by 1.35 Other xfmr's are worse still. ### add more filter C... and power factor gets even worse still. If the ripple is low where you want it, I wouldn't worry about adding anything else that may draw more current.### I'm fine with the ripple... it's under 1%. I'm worried about the power factor.... and if something can be done.,.. great... if not.... no big deal... since nobody is on TX for that long anyway.... with vox/ roundtables etc. ## Being able to do something about 480 va CCS... caused by magnetizing current would be nice. I suppose one could just shut off the HV supply... if you knew you were gonna be on RX for an hour... and just leave the fils on. Only a few seconds to get the HV back online.... then ph Nuke station #6... and tell em to pull the rods out. Later..... Jim cap tothetry it myself. It gets installed directly in parallel with thepri of the plate xfmr. [this is for a C input HV supply]. wentwrong value. What I did notice was the magnetizing current capsup on the pole pig... from 1.8A to 2.3A ! The magnetizing upresistor]to max V. [u always have current flowing through the drop withThe plate xfmr is always sucking magnetizing current... even becausenothing connected to the secondary. ofdrawsload. The idea I had was to use a small possibly sped up vacthe excess1.8 A. My electrician buddy sez they never oversize vault biggermagnetizing current. HVDahl draw LESS magnetizing current than the smaller 120 lb poleThese secC input filter. Maybe I'm confused here... but it appears theloadis not the XL load of the xfmr... but the HV C filter on the mightside ? behasfruitless....... or maybe it works on TX... but correction cap aboutto be switched out on RX. IF it works... how do you go throughsizing the correction cap ?.... and how much current flows the correction cap ??? |
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Re: ARRL - Political - was: Filament Voltage regulator
On Nov 12, 2006, at 5:42 PM, FRANCIS CARCIA wrote:
In West Hollywood, this would be considered a perquisite. None of this was news to me after learning that.Correct, Frank, which is why they adopted the priestly vow of not to do women 9-centuries ago. It is all about money (sick).Right, and Bernard Law gets an allowance of c. $12,000 a month. ... ... ...R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: 3-500Z socket.... Johnson vs Eimac
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
requires a high-pressure centrifugal blower, and Ham amps used an ordinary centrifugal blower. pressure.### See my note above. A 3-500Z only requires a .08" h2o RICH SEZ... Correct, but Eimac's 0.82" water column spec is the pressure differential across the socket, and that usually means a fairly noisy blower. ### The actual spec for a 3-500Z is 13 cfm @ .13" h2o...... or 26 cfm @ .13"... for a pair. And that's for 500/1000 w CCS anode diss. Now .13" pressure is zip imo. Heck... the requirements for a SINGLE 3CX-800A7 are 19 cfm @ .5" A 4CX- 250R is 6.4 cfm @ .59" A blower capable of .13" h2o is NOT noisy. The puny blower in the L4B is dead quiet.. a lot quieter than the 1" diam tiny fan in my outboard 30 vdc supply for the yaesu MK-V. [the noise in the mk-v power supply is from the slots in the cab... not the actual 1" diam fan] corners along one edge is light enough to rise automatically withA square of varnished cardboard with two nickels glued to theflap that hinges up to let the air out. It just doesn't look as the airflow passing through an 8170. When the amp is off the cardboard flops down, keeping spiders from constructing webs on the insides. ### well, at least you got 2 x nickels to rub together ! red radiation?RICH SEZ... So objects that glow red-orange do not exhibit infra-### here's the interesting bit. Eimac states the glass tubescool by infared radiation.... well my natural gas fireplace puts ### If a 3-500Z is suppose to cool partially via infrared radiation... I think they are full of it. I can put my hands on the left side cabinet... [which is flat black... in and out]... and it's stone cold... and also has zero air on it. You can take the cab right off... and put ur hand [carefully] on the insides anywhere... and feel no heat from the infrared radiation. The outsides of the chimney's are hot [dead cxr, tubes red]... but that's from a lack of air. The puny blower in the L4B is good for 600W CCS anode diss... NOT 1kw. The point is.. the infrared radiation is not heating anything else up in the cabinet. The Fluke 62 IR confirms this. ### Another point here. The 3CX-800A7 has got 60% MORE anode diss than a 3-500Z.... but only requires 46% more CFM than a 3- 500Z. So much for..."cooling" by infrared radiation. ### Rich... if you operated the SB-220 at 1500W out RTTY for 1 hr... you wouldn't have enough cooling on the tubes. You would have to use a real noisy fan. [asuming a real pwr supply, and loads of air on tank components... like that flaky bandswitch]. The point here is the fan set up in the SB-220 is designed for 600 w out cw operation [400 w peak anode diss, 200 w CCS].... and 1200 w pep out on ssb [800 w peak anode diss, maybe 400-500 W CCS] that's it.... and that asumes you are not TX'ing all the time either. Later... Jim VE7RF ...R L Measures, AG6K, 805.386.3734 |
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Re: 3-500Z socket.... max current ratings
pentalab
--- In ham_amplifiers@..., Bill Turner <dezrat@...>
wrote: them into account. I would just caution anyone on adding an arbitraryXX% of airflow "just in case". If you are serious about your ampdesign, you should test the seal temperatures under any and all operatingfilters, high ambient temperature, etc, etc. Only then can you be sure yourmanufacturers specify a maximum value. If a designer ONLY measures airflow and### Highly agreed. Seal temperature is the final determining factor. Use of temperature sensitive paints are easy to use... they are well documented in care and feeding and other literature... they will melt and turn cystaline, when the pre-set temp is exceeded. Due to the normal chimney setups... even my Fluke mini 62 can't be pointed at the seals... only the portion of the metal anode above the chimney.... which is nice to know.... but not what we really want to know. On a glass tube... a Fluke 62 will work fine on the top seal. However,you still can't get at the bottom pins/seals very easily. Later... Jim VE7RF 13:21:24 -0000, "pentalab" <jim.thomson@...> wrote:bases commercialtheir airflow specs on 225 deg C.. allowing a 25 deg C "safety bat.gear [ real broadcast gear... not Ameritron ham stuff] will take dirtyThat will factor in ducting from blower to plenum... and also air filters, right angle bends etc.<snip> |
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Re: Inrush filament current protection
pentalab
--- In ham_amplifiers@..., "Robert B. Bonner"
<rbonner@...> wrote: RIGHT NOW that had me thinking the same thing. ### huh ? AS long as you have a relay/contactor/ ckt breaker that opens OFF BOTH sides of the 240v line... anything beyond that is a moot point...and legal. BEWARE... if using fuses on the primary.... they HAVE to be 240 V rated... NOT 120 V rated. Here's why. IF only one fuse in one leg of the primary blew open... and the 2nd fuse in the other leg was intact....you could end up in a situation where 120 v is fed to one side of the plate xfmr primary.... where it will simply pass throught the typ .08 ohm dc resistance primary... then back to the OUTPUT side of the blown fuse.[call this leg #2] Meanwhile... on the INPUT side of the blown fuse.... you still have 120 V [coming from leg #1.] The potential difference across the blown fuse in leg #1 will be ...240 V. IE: with EITHER fuse blown [but only one], you will have 240 v across an open fuse.... so DON'T use 120 V rated fuses in either leg of a 240 v LINE. ### ALSO BEWARE.... some amps like the L4B... use two SEPARATE circuit breaker's... one per hot leg... and NO tie bar between em. These are usually the type that resemble a 3agc fuse holder.When these type of breakers open up... they extend outwards. wire plus neutral. ### partially agreed. ALL wire now comes with a bare or insulated grnd...whether u want it or not. The grnd is NEVER considered any more in the wire count. So, you either ask/order 2 conductor wire.... OR 3 conductor wire. 2 x conductor wire comes with a grnd... so total wires = 3. 3 x conductor wire also comes with a grnd... so total wires = 4. IE: you ask fo 3 x wire XXX ga.... u get a total of 4 x conductor's. practices you could get by with only 1 resistor in the step start. #### The electrical code will state on a 240 v circuit you will require a TWO pole breaker..and/or a TWO pole relay/contactor... to open off BOTH sides of the line. After that.. they could care less if u install a 12.5 ohm resistor in EACH hot leg... or a 25 ohm resistor in just ONE hot leg. Putting a resistor in both legs is a waste of effort. It's total LOOP resistance we are concerned with here. like a filament transformer that runs on 110 you would want to have 2 resistors in the step start. ### Agreed. BUT.... on an amp like the L4B.. and 99% of em... that have a SEPARATE fil xfmr.... the fil xfmr will ALWAYS have it's own dual 120 v primary's.... which can be wired in parallel for 120v... or in series for 240 V. The only exception to this.. would be if in a condo with 208/120V wiring per suite. You can then run 208 V into the plate xfmr [wired for 240V.. so u end up with slightly less plate V].... and run 120 V to the fil xfmr [wired for 120V... so fil gets correct V] ### IF, indeed one had a fil xfmr that ONLY ran on 120v.... then, you would have to ensure that the hot leg feeding the fil xfmr.. came from the SAME side of the 240 v line.... as your single step start resistor.... so when step started... you step start BOTH the HV supply AND the fil xfmr... at the same time...from the same source. ### No you wouldn't. That could only happen if one side of the 120V fil xfmr [or any other 120 v device] was tied directly to the chassis.. instead of the neutral. That isn't going to happen.. since it's not allowed... would violate every electrical code in North America. On a similar note... you NEVER bond the neutral to the chassis.... that also violates every electrical code in NA. The ONLY thing bonded to the chassis is the grnd wire. With any shorts from either side of line to chassis... the grnd wire handles the full fault current. ### On circuits which require a huge 240 V load... like a HV supply.... but only a tiny load for the 120 V load... like say a 120 V blower... some tiny xfmr's for a T/R supply, etc... then it would be ok to use a smaller neutral.... as long as the neutral could handle the entire fault current... IF a line to neutral short occured. EG: 2 ga wire for each hot leg... and a 100 A main breaker in panel... but only 6 ga wire for the neutral.... and also 6 ga wire for the grnd. ### You see that in the Henry 8 k manual. They do that to run the 120 v Dayton blower. In EU/UK... they don't use a 3 wire 220 v line. They only have 2 x wires from the pole pig... with 220 v across em. One side of the line is bonded to earth ground... so one leg is hot... the other leg is valled neutral. That way, they only have to fuse the ONE hot leg... and any switches, relays, etc, are only required to be single pole types... for the one hot leg. As per the 8K... when you look up the Dayton blower part number they spec in their parts list in their manual.... and cross reference it to the Dayton blowers on Grainger's website... turns out it's the 230 V version of the same blower... and in fact, the 240/120 V step down xfmr shown in the schematic and also the picture drawings.... doesn't exist. ## Notice on 240 V clothes dryers... they always include a neutral... to run the 120 V blower. Seems stupid to me. They shoulda just used a 240v blower... and could have eliminated the requirement for a neutral..... just like a 240 v hot water tank.... none of which have a neutral... since the heating els run on 240 V only. Another option is 4 wire circuitry where you have 220 plus neutral and ground. What a pain with the outlets etc...### what's the problem with the outlets ??? A 30 A dryer outlet comes with 2 x hots, one neutral... one gound. A 40 A stove is exactly the same thing. Ditto with 20 A circuits. brewing does it really matter? NAW it will turn on and work. ### with HB HV supplies... you don't need an outlet. You just hardwire the 2 ga wire directly to the line side input of the front or rear panel mounted breaker. OR hardwire the 2 ga wire directly to the jumbo contactor input..... either way... you still have the breaker in the main panel that feeds this mess. You can buy 75/100/150/200 A outlets... cost a small fortune. You don't need em.... just hardwire the big wire in..... and when working on the amp.... kill the breaker in the main panel. IF the HV supply/amp needs to be rolled over to the bench... just disconnect the 4x wires at the HV/amp end. prettier, double pole relay, pair of resistors, double pole relay all in line. Nice pretty yellow adjustable time delay relay. ### Here's what I do. I use 25 ohms in one leg only... and only one contactor to short out the resistor. The kicker is.. I use a pair of paralled 50 ohm resistor's to make up the 25 ohms ! If one resistor ever opened up... the 2nd one [albeit 50 ohms] is still in the circiut. That way... I can never shunt an open single resistor with the step start contactor... and slam a huge load on the diodes.... IE: no step start at all... which would be a disaster with 100-200 uf C input filter. These large metal finned resistor's you see made by DALE and other's, works perfectly for the step start R. Just bolt it to metal chassis anywhere. Cuz of our magnetizing current.... I use a min of a 100w - 200 W rated units... EACH. You will have the entire 240 V dumped across em when you 1st hit the switch. When everything settles down... I still have 2 A of magnetizing current flowing through em..[100/200 w]... then they get shunted. ## I also use the yellow /white adjustable Time delay relay. The TD relays are all DPDT 10 A contacts.... which are used to activate the coil of the step start contactor. The big step start contactor has loads of AUX contacts... which are wired to the amp key line.... ditto with main incoming contactor.... so you can't key the amp unless all the contactor's are actually operated. We use loads of 120 v neons as well.. status lamps... to tell us instantly, where a problem is.. works slick.. if and when it comes time to trbl shoot anything. A row of 3agc fuses [and more neons on the output sides of the fuses] are the various feeds for the blower, TD relays, small xfmr's for T/R relays, contactor's etc. ### On the big stuff.... we use a separate Time delay for the fil xfmr... which has it's own step start resistor/ variac, etc. The fil TD is set for 8-10 seconds.... the HV delay is set for 15- 25 seconds. The blower over run TD is set for 15 mins. -also have an airflow vane/ switch, retrofitted inside the blower. Contacts of the airflow switch are wired to the coil of a small relay.... whose contacts open off the 240 V to the fil xfmr. The last thing you want is no air to a tube... esp when it's 30' away... in another room. The slick thing about this setup is... IF the commercial AC power goes off.... everything shuts down. When the power comes back on.... everything just goes through it's normal step start sequence etc. You can't key the amp... until it's all finished. Later... Jim VE7RF [mailto:ham_amplifiers@...] On Behalf Of Garry Drummondresistor in both sides of the 240 volt line for inrush current protection orwould a single resistor of adequate size in one leg do the job? I amspeaking of the typical amplifier running a pair of 3-500's. |
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Re: ARRL - Political - was: Filament Voltage regulator
FRANCIS CARCIA
My next door neighbor growing up wanted to be a priest. In the late 60s he spent 3 years going to school then all of a sudden dropped out.?I asked him why he changed his mind a couple years later. He told me he was afraid to go to bed at night for fear of who would join him. Sick. None of this was news to me after learning that. Church is too cheap to support priests who marry. It is all about money (sick). Law (Boston)?should have also gone to jail but was promoted. R L Measures wrote:
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Re: Inrush filament current protection
craxd
For the life of me, I can't figure out why you would need one for
each line lead? If the voltage drops, the current rises making the same output power from the transformer. The same amount of power will be drawn either way if the amps output is the same. Example, 220Vac x 14 amperes is 3,080 watts, and 110 Vac x 28 amperes is 3,080 watts. A 25 ohm resistor at 110 Vac or 220 Vac would see the same power in watts since when the voltage drops, the current rises, and when voltage rises to 220 vac, current drops by 1/2. Does the surge current increase more than double by dropping the voltage down to 110 Vac? The only difference in the primary windings are having them either in series or parallel. Thanks, Will --- In ham_amplifiers@..., R L Measures <r@...> wrote: resistor in both sides of the 240 volt line for inrush current protection orAmplifiers that run on two voltages need two step-start resistors, |
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Re: Can a ..power factor correction cap be used on the input of a Plate Xfmr ??
craxd
Jim,
I've seen these used, but they were used in smaller DC supplies. I have several books on the subject and will look it up. That value though seems way to much at 35 uF for this. Placed across the primary leads, it will start looking like a short or a leak if big enough. That's why your seeing an increased current. The cap is causing more current to be drawn or mag I + cap I. All transformers have magnetizing current which is low compared to their output power. However, the larger the transformer, the more this will be. Also, the higher the flux density its ran at, the higher it will be. For this type transformer service, the power factor should be about 0.95 or so. If the ripple is low where you want it, I wouldn't worry about adding anything else that may draw more current. Best, Will --- In ham_amplifiers@..., "pentalab" <jim.thomson@...> wrote: to try it myself. It gets installed directly in parallel with theup to max V. [u always have current flowing through the drop resistor]of load. The idea I had was to use a small possibly sped up vacthe cap.These xfmr's typ have a .9 pwr factor... and even worse with a bigger HVload is not the XL load of the xfmr... but the HV C filter on the secbe fruitless....... or maybe it works on TX... but correction cap has |
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Re: ARRL - Political - Hiram Percy maxim
craxd
Hirams Percys father, Hiram Stevens Maxim was the daddy of the Maxim
machine gun that helped cause all the carnage in WWI. Though the Browning machine gun eventually won out during US government testing, the Maxim was still used in Britan. It went out of production though and became the Vickers machine gun. The size came down and others had increased capacity like the Thompson "Tommy" gun. This was the mobs favorite in the 20's. The same Browning 30 and 50 cal's are still being produced and used today. The Vickers was used up to 1968 by Britan. I would think that dealing out death ran in the Maxim family. The first way was quickly, and the second silently. Hiram Stephens brother Hudson Maxim was also a military inventor, specializing in explosives. Again, a death dealer. Just because Hiram Percy was one of the founders of the ARRL, doesn't hide his family history. Best, Will --- In ham_amplifiers@..., R L Measures <r@...> wrote: of headphones -the firearms silencer, Hiram P. Maxim, wearing a set of everythingbut strangely he is given no credit whatsoever for his brilliantNot according to history, Jim. hisfrom air conditioners to cars.. planes etc. He didn't like the way "Maximinvention? silencer" gun attachment. Son and nephew of famous inventors,Maxim graduated from Massachusetts Institute of Technology, then inBoston, at age 16 ..."they do not silence the sonic crack of a bullet traveling faster thanthe speed of sound (c. 1060 feet per second), so even a 22-LONG RIFLEexits out the side from the gap between the receiver and the cylinder.towel around the revolver to muffle the cylinder gap noise as well asthe muzzle-blast when he terminates the neighborhood asshole.pellets typically leave the barrel about 300-ft-sec above the speed ofsound. like### Here's a question. Can one still be an ARRL life member ??The last I heard, yes.As $500.00 to $750.00R L Measures, AG6K, 805.386.3734 |
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Re: Inrush filament current protection
On Nov 12, 2006, at 7:29 AM, Garry Drummond wrote:
When running an amp on 240 volts, is it necessary to put a resistor inAmplifiers that run on two voltages need two step-start resistors, but those that run on one V need only one R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
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Re: Inrush filament current protection
Robert B. Bonner
Garry,
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That is a great question. I have a couple projects going together RIGHT NOW that had me thinking the same thing. It depends on if you cheat or not. OK what does that mean? 220V wiring is 2 wire plus ground, not 2 wire plus neutral. If you use legal by code 220/221V (whatever it takes) building practices you could get by with only 1 resistor in the step start. If you cheat and have some 110 volt circuitry in the amplifier like a filament transformer that runs on 110 you would want to have 2 resistors in the step start. In this situation you would have current flow on the GROUND LEAD. That's why professional grade equipment has a 220 - 110 step down transformer on board. Another option is 4 wire circuitry where you have 220 plus neutral and ground. What a pain with the outlets etc... A guy should follow good construction practices. BUT for home brewing does it really matter? NAW it will turn on and work. Just an FYI, I use a double resistor. It just happens to look prettier, double pole relay, pair of resistors, double pole relay all in line. Nice pretty yellow adjustable time delay relay. BOB DD -----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Garry Drummond Sent: Sunday, November 12, 2006 9:29 AM To: ham_amplifiers@... Subject: [ham_amplifiers] Inrush filament current protection When running an amp on 240 volts, is it necessary to put a resistor in both sides of the 240 volt line for inrush current protection or would a single resistor of adequate size in one leg do the job? I am speaking of the typical amplifier running a pair of 3-500's. Thanks, Garry - WR4R Yahoo! Groups Links |
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Inrush filament current protection
Garry Drummond
When running an amp on 240 volts, is it necessary to put a resistor in both sides of the 240 volt line for inrush current protection or would a single resistor of adequate size in one leg do the job? I am speaking of the typical amplifier running a pair of 3-500's.
Thanks, Garry - WR4R |
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Re: 3-500Z socket.... max current ratings
Bill Turner
All of Jim's points are valid and a good amp designer will take them
into account. I would just caution anyone on adding an arbitrary XX% of airflow "just in case". If you are serious about your amp design, you should test the seal temperatures under any and all operating conditions it may run into such as high altitude, dirty air filters, high ambient temperature, etc, etc. Only then can you be sure your design will work under those conditions. My point was, and is, that measurements of airflow, back pressure, etc, are nice but what counts in the end is the temperature of the tube seals. That is the weak point and that is why tube manufacturers specify a maximum value. If a designer ONLY measures airflow and ignores seal temp, he is asking for trouble down the road. I realize for most of us homebrewers that isn't really practical to perform all those tests in all cases, but we should try to come as close as we can. Bill, W6WRT ------------ ORIGINAL MESSAGE ------------On Sun, 12 Nov 2006 13:21:24 -0000, "pentalab" <jim.thomson@...> wrote: <snip> <snip> |
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