On the subject of water cooling media. I am a professional welder and they make
a product for tig torches that are water cooled. TIG torch coolant holds up
very well for years at a time under a very abusive environment. I also use RV
water line antifreeze and that seems to be a very effective medium for water
cooling everything from tig torches to solid-state devices it has excellent
long-term stability and Electrical performance. I haven't experienced any high
voltage break down when using this product for at least three years at a time.
Jeremy Engbrock N0NZG
> On Feb 22, 2017, at 1:06 AM, amps-request@contesting.com wrote:
>
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> Today's Topics:
>
> 1. Checking Filament Voltage (Jim Thomson)
> 2. SS amps watercooling - was PowerGenius XL (Jim Thomson)
> 3. Re: Checking Filament Voltage (MU 4CX250B)
> 4. Re: SS amps watercooling - was PowerGenius XL (Paul Christensen)
> 5. Re: SS amps watercooling - was PowerGenius XL (Ron Youvan)
> 6. Re: SS amps watercooling - was PowerGenius XL (Roger (K8RI))
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 21 Feb 2017 18:45:15 -0800
> From: "Jim Thomson" <jim.thom@telus.net>
> To: <amps@contesting.com>
> Subject: [Amps] Checking Filament Voltage
> Message-ID: <F3609424867646939875B851B4E89F99@JimPC>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Date: Tue, 21 Feb 2017 14:24:53 -0700
> From: MU 4CX250B <4cx250b@miamioh.edu>
> To: Bill Turner <dezrat@outlook.com>
> Cc: Amps group <amps@contesting.com>
> Subject: Re: [Amps] Checking Filament Voltage
>
> The simplest solution for amps with separate filament xfmrs is
> probably to install an inrush current limiter in series with the
> xfmr's primary winding. These look like disc capacitors and cost about
> a dollar. I use them frequently on any circuit that has a initial
> surge current, and a constant load current in equilibrium.
>
> Probably the easiest amplifier to install one in is the drake L4B. I
> removed the jumper on a terminal strip and replaced it with the
> current limiter. Took five minutes, most of which was spent removing
> the screws on the bottom cover.
> 73,
> Jim w8zr
>
>
> ## watch out. They run HOT in normal operation, with a normal constant
> load.
> Which is all fine, provided the inrush current limiter is not in the airflow
> of any blower.
> If it gets air blown onto it, its resistance will start to climb = bad news.
>
> ## In the case of the drake amp, the fil xfmr and bifilar is in a separate
> compartment
> from the pressurized sockets. So the limiter, in that case will work good.
>
> ## I used an external 25 ohm step start on my Drake L4Bs...in series with
> one leg of the
> incoming 240 vac line. Then it step starts both the B+ and the fil
> xfmr..at the same time.
>
> ## I used a DPST relay to apply the 240 vac. A SPST relay is used to shunt
> out the 25 ohm
> resistor. Both relays and resistor reside in their own small box. Small
> control cable from that box
> runs over to the operating position, into a small mini box, with 2 x
> miniature toggle switches on it.
> Switch #1 turns on the DPST relay. Switch #2 turns on the SPST shunting
> relay.
>
> ## In normal operation, 1st toggle is thrown, and B+ comes up to 75-80 % .
> Tube fils
> come up to 75-80% normal brilliance. 2nd toggle is thrown, and both B+ and
> fil come up to
> full voltage.
>
> ## when toggling between low B+ setting..and high B+ setting, the 2nd toggle
> is thrown 1st,
> putting the step start 25 ohm resistor back into the circuit. Then hit the
> rocker switch, that
> increases B+ to the higher setting. Then operate the 2nd toggle, and shunt
> out the step start
> resistor.
>
> Jim VE7RF
>
> ------------------------------
>
> Message: 2
> Date: Tue, 21 Feb 2017 19:20:15 -0800
> From: "Jim Thomson" <jim.thom@telus.net>
> To: <amps@contesting.com>
> Subject: [Amps] SS amps watercooling - was PowerGenius XL
> Message-ID: <16951CB2D4224F29AB49C05781B0A027@JimPC>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Date: Tue, 21 Feb 2017 20:11:08 -0500
> From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
> To: amps@contesting.com
> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
>
> Not sure what you are disagreeing with. Distilled water presents a high
> resistance when first used, BUT, distilled and de-ionized water is ion
> hungry, or rephrased, quite corrosive. It will take the strength out of
> brass fittings to the point where you can crumble them between your
> finger.. IE, hose barbs. It is the metal ions that increase the
> conductivity. Tap water (with no salt) is still conductive)
>
> As the water ages, the dissolved metal ions lower the resistivity.
> That's why we monitor the resistivity. Eventually the resistivity gets
> low enough that the water needs to be replaced with, fresh, clean,
> distilled water.
>
> 73, Roger (K8RI)
>
> ## distilled water is water that has been boiled, and the steam
> condensed back to water. Its pure water. AFAIK, distilled
> water is not ion depleted. If it is ion depleted, bad news, it will
> eat the insides out of any external rad used....esp Aluminum.
>
> ## de-ionized water is a chemical process, so you end up with pure
> water..... without having to go through the boiling process.
>
> ## You cant use 100 % distilled water in any eng or supercharger closed loop
> system, unless corrosion and rust inhibitors are used. 100% distilled water
> extracts a lot more heat vs a 50-50 mix of distilled water + glycol.
>
> ## so dunno if distilled water would work in a SS application. Do you
> really require
> the high resistivity for a 50 vdc device ? I thought there was an
> electrical insulating
> barrier between the LDMOS and its mating heatsink. If so, water resistivity
> is
> a moot point.
>
> ## Plane jane tap water is used for water cooled dummy loads. 20 kw into 50
> ohms = 1414 V peak. Those type of dummy loads are not an issue. Available
> up to 200 kw.
>
> Jim VE7RF
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Tue, 21 Feb 2017 20:26:04 -0700
> From: MU 4CX250B <4cx250b@miamioh.edu>
> To: Jim Thomson <jim.thom@telus.net>
> Cc: "amps@contesting.com" <amps@contesting.com>
> Subject: Re: [Amps] Checking Filament Voltage
> Message-ID: <5472095878531626573@unknownmsgid>
> Content-Type: text/plain; charset=UTF-8
>
> Sent from my iPhone
>
>> On Feb 21, 2017, at 7:45 PM, Jim Thomson <jim.thom@telus.net> wrote:
>>
>> Date: Tue, 21 Feb 2017 14:24:53 -0700
>> From: MU 4CX250B <4cx250b@miamioh.edu>
>> To: Bill Turner <dezrat@outlook.com>
>> Cc: Amps group <amps@contesting.com>
>> Subject: Re: [Amps] Checking Filament Voltage
>>
>> The simplest solution for amps with separate filament xfmrs is
>> probably to install an inrush current limiter in series with the
>> xfmr's primary winding. These look like disc capacitors and cost about
>> a dollar. I use them frequently on any circuit that has a initial
>> surge current, and a constant load current in equilibrium.
>>
>> Probably the easiest amplifier to install one in is the drake L4B. I
>> removed the jumper on a terminal strip and replaced it with the
>> current limiter. Took five minutes, most of which was spent removing
>> the screws on the bottom cover.
>> 73,
>> Jim w8zr
>>
>>
>> ## watch out. They run HOT in normal operation, with a normal constant
>> load.
>> Which is all fine, provided the inrush current limiter is not in the airflow
>> of any blower.
>> If it gets air blown onto it, its resistance will start to climb = bad news.
>
> Very good point, Jim. Yes, ICLs run hot and must be kept out of a
> cooling airflow. I normally do not shorten the leads to the ICL, and
> insulate the leads with teflon tubing. I position the ICL so that it
> is suspended by its leads (about an inch on each lead) and not
> adjacent to other components.
>
> My Fluke 87-5 has a peak reading feature, so in evaluating the effect
> of the ICL, I replace the fuse (if one is in the primary xfmr circuit)
> with a 1ohm resistor and measure the peak current before and after
> installing the ICL. It's also good to measure the steady-state current
> after the ICL has been on awhile. The specific device has to be
> selected carefully.
> 73,
> Jim w8zr
>
>
> ------------------------------
>
> Message: 4
> Date: Tue, 21 Feb 2017 22:48:50 -0500
> From: "Paul Christensen" <w9ac@arrl.net>
> To: "'Amps Amps'" <amps@contesting.com>
> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
> Message-ID: <005701d28cbe$9509ad80$bf1d0880$@arrl.net>
> Content-Type: text/plain; charset="us-ascii"
>
>> ## Plane jane tap water is used for water cooled dummy loads. 20 kw into
> 50 ohms = 1414 V peak. Those type of dummy loads are not an issue.
> Available up to 200 kw.
>
> Recently purchased a NOS 5KW Altronic Omegaline load. Connect a garden
> hose, crack open a faucet, set reasonable water flow and warm water comes
> flowing out to water the yard or fill the pool. Just throw the coax out the
> shack window when load testing! Works great.
>
> The plan is to add a flow sensor to the inlet port. The sensor has N.C.
> contacts when flow is adequate and can be linked back to the transmitter or
> amplifier as an interlock. If a problem develops with the flow rate (e.g.,
> kinked hose) the interlock opens, kills R.F. and saves a very expensive
> glass resistor.
>
> Paul, W9AC
>
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 21 Feb 2017 23:06:24 -0500
> From: Ron Youvan <ka4inm@gmail.com>
> To: amps <amps@contesting.com>
> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
> Message-ID: <433b31e1-3907-b43b-3156-baf676f727fa@gmail.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> Jim Thomson wrote:
>
>> ## de-ionized water is a chemical process, so you end up with pure
>> water..... without having to go through the boiling process.
>
> De-ionized water IS NOT pure water, the de-ionizing process does NOT
> remove silicates that are abundant is some parts of the world, very
> present in the central Florida aquifer. It settles out creating a
> white ceramic like thermally insulating coating on things that get hot.
> De-ionized water is not the same as steam distilled water, here.
> --
> Ron KA4INM - Youvan's corollary:
> Every action results in unwanted side effects.
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 22 Feb 2017 02:06:31 -0500
> From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
> To: amps@contesting.com
> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
> Message-ID: <83e99bf4-bf1c-c5a1-ba88-31d3b3111ab6@rogerhalstead.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> A properly designed SS amp running Class A, AB1, AB2, B, and C uses
> about the same power and class as a tube amp may require less cooling
> than the tube amp as there is no heat from a filament. Many tube amps
> in the legal limit power range require fan cooling directed at the
> filament pins and lower seals.
>
> Only SS amps using exotic modes require less cooling.
>
> To me, it makes more sense to use modern devices that can run 2400 W for
> a pair of transistors per module, use a pair of modules through
> combiners, design the whole works for the legal limit and you will get a
> super clean amp for less than the cost of an equivalent tube amp and
> without the fan noise, without the need for a lot of complicated
> monitoring and protection circuitry.
>
> Adding hardware predistortion gives an outstanding signal, while dynamic
> predistortion gives an even cleaner signal.
>
> I've used several SS, air cooled amps in the 1 to 1.2 KW range and they
> did not suffer from excessive heat. In fact, they were very quiet,
> unlike my tube amps.
>
> The only legal limit amp I have that is quiet is my old HT33B, but that
> legal limit was quite a bit less than today's.
>
> 73, Roger (K8RI)
>
>> On 2/21/2017 9:26 PM, Jim Thomson wrote:
>> Date: Tue, 21 Feb 2017 20:11:42 +0000
>> From: Manfred Mornhinweg <manfred@ludens.cl>
>> To: amps@contesting.com
>> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
>>
>> Hi all,
>>
>> It's my humble opinion that this whole thread on how to cool high power
>> solid state amplifiers, using water (or evaporation, oil, freon,
>> whatever) is on the wrong track.
>>
>> Instead of using high power amplifiers built basically like small signal
>> amplifiers on steroids, that is, transistors acting as RF-controlled
>> variable resistors that drop more or less of the supply's voltage to
>> produce the desired waveform, and thus incur in huge power loss that has
>> to be removed as heat, we should be building high efficiency amplifiers,
>> in which the transistors act as RF-controlled switches, so that the
>> power loss is tiny and can be easily handled with very modestly sized
>> heatsinks.
>>
>> The broadcasters have been doing it for ages. It's about high time that
>> we "technologically advanced" hams do it too. A handful of hams are
>> actually doing it, but most hams still cling to antiquated and
>> inefficient technology, and that's really a shame.
>>
>> I don't mean to blame any individual ham. For a single individual it
>> does take a considerable effort to think totally outside the box and
>> come up with a good, highly efficiency, low distortion power amplifier
>> that doesn't break the bank. But collectively we should be able to move
>> standard ham equipment technology from class AB linear amps to something
>> much better.
>>
>> Manfred
>>
>> ## which broadcasters are using SSB ???
>>
>> Jim VE7RF
>>
>>
>>
>>
>> _______________________________________________
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>>
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>
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>
> End of Amps Digest, Vol 170, Issue 42
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