Mega Watt Power Supplies?

[KD8TUT]

Hi guys,

Are any of you familiar with the PSUs made by this company? I'm interested in any impressions you may have?

http://www.megawattpowersupplies.com/

[WZ7U]

Can't speak directly to them myself, but I do run old server supplies at my place for HF. Set to 13.8v, 82A max per unit as well as a 5v terminal. Bought these for $20 each about 3 years ago used. Kinda reminded me of those.

Sorry I'm not more help.

On edit - HP branded server supplies, cycled out for age I'm sure. First learned about them from a friend into RC stuff. Apparently that demographic uses them to charge batteries.

[kb2vxa]

Interesting. When I read "Built for... ...CB Radio... ...or a linear amplifier" my mind instantly flashed here https://www.youtube.com/watch?v=ef6z3MaLOrU (skip forward to 0:55 ) then at 1:13 jump to here https://www.youtube.com/watch?v=fEAGHixZHJg for more incredible mindlessness.

[koØm]

Interesting. When I read "Built for... ...CB Radio... ...or a linear amplifier" my mind instantly flashed here https://www.youtube.com/watch?v=ef6z3MaLOrU (skip forward to 0:55 ) then at 1:13 jump to here https://www.youtube.com/watch?v=fEAGHixZHJg for more incredible mindlessness.

"Dave-made, Dave-made, Dave-made".......


The fact that the company's advertisements are directed at "Ham Radio" (not Amateur Radio) and list "CB Radio" on it's front page tells the whole story; a D.C. power supply that delivers 15 volts direct current at 400 amperes (6.0 Kw!); good to power a "128 pill" 12 volt bipolar transistor RF amplifier.

How does that look on the primary side of the transformer, *if* this PSU was 100% efficient (it's not), it would pull 27 amps on a 220 volt A.C. circuit (234 vac in reality but, round numbers are easier).

Towards the end of the page, he misspells "Reviews" and his "Reveiws" come from the WWDX free-band web site.

Look harder, you can do better if you want to.

[N8YX]

Years ago, my friend Hi (W8UXE - SK) came across some 100-150A linear supplies that were designed to deliver unregulated, ~16VDC to industrial computer equipment. His solution to regulation was to equip each of several feeds with a regulator/pass transistor arrangement which would supply 12-13VDC @ 35-40A to each radio that required DC power. A larger pass transistor setup - higher Ic devices, with more of them in parallel - allowed currents of upwards of 100A for use with the odd HF or VHF amplifier.

We measured the raw output @ >100A loading and most of these would only sag around 0.5V.

I wish I could remember who made the supplies.

[WØTKX]

They look familiar in the form factor. Like the PSU types for those bigass road messaging signs that I used to work on.

I have 4 28 VDC 40 amp supplies squirrelled away (rescued from the recycle bin at the old employer) that got tossed.

Because we went from Skyline displays to Daktronics. Refurbished spares. So yea, solid state amps. Maybe.

[kb2vxa]

My mind got side tracked by idiot CBers and I didn't continue down to the spelling errors red flag. What I did notice but failed to mention was a HUGE red flag, the misuse of a clamp on AC ammeter on DC leads. This looks like a product of The Donald with his child's mind, Mega What I wonder.

[WØTKX]

No. The Greenlee CM-1550 clamp meter measures DC amps just fine, as do many clamp meters.

Using a hall effect sensor, you can still use it for DC, just mind the direction (polarity).

Your confirmation bias regarding CeeBee and/or poor engrish is showing.

https://www.manualslib.com/manual/272034/Greenlee-Cm-1500.html?page=10#manual

https://www.explainthatstuff.com/hall-effect-sensors.html

[koØm]

My mind got side tracked by idiot CBers and I didn't continue down to the spelling errors red flag. What I did notice but failed to mention was a HUGE red flag, the misuse of a clamp on AC ammeter on DC leads. This looks like a product of The Donald with his child's mind, Mega What I wonder.

I saw that!

Actually had me questioning my own intellect.

ETA: If I were still "working" I would invest in one of those new fangeled DC reading clamp on ammeters, for my involvement now days, the old AC clamp in will have to do.

[kb2vxa]

Clamp on >DC< ammeter, that's a new one on me. My last job as a plant electrician was before those critters came on the scene, I used an antique analog meter to check phase balance. Anyway, I wouldn't trust a tech writer who can't spell AND is too dumb to use a good spell checker and/or use one of scores of Internet dictionaries when the spell checker doesn't look quite right. In this case the tech writer is a CB Bubba with a 6th grade education that participates in "shoot outs" like the one with arcing antennas and bitches about the "beepers" on 10 meters.

What looks like a bargain can turn into a disaster, especially when you don't know the source and find out too late. Those PSUs look like pulls, pulls from what and where? Reputable dealers have become clearing houses for sellers, many in China, and they don't screen sellers that use their web site. Recently I decided to dig into my computer and replace the drives, C Main (OS and apps) became a Seagate 240GB SSD and D Data Volume (videos, music, etc.) was a 4TB Seagate Barracuda became a Seagate Terascale designed for server data storage in a data center. The whole idea being the drive used most being designed to run continuously and warranted for 5 years should be a brute made to last. It passed a SMART test with flying colors, POH (power on hours) 0, looked to me to be NIB half priced. No such luck, in a week it started grinding coffee, the Barracuda went back in awaiting delivery of a 4TB Seagate Exos 7E8 that I was going to buy until I spotted the "bargain". Now the Exos is D Data Volume and the Barracuda holds two compressed backups, one of each drive. Being it only spins up for 8 hours a month I expect it isn't going to die any time soon. Reading users reviews (read suckers) I discovered they use software to roll back POH to zero so it reads SMART like a new HDD, like an old trick now illegal used car salesmen used, disconnect the speedo cable and using a drill roll the odometer back. Unfortunately legislators haven't caught on to these electronic cheats.

That's what I went through trying to be a cheapskate and got punished for it, here's the run down on the history of the Seagate Terascale HDD. It's an obsolete server pull, if you see it for sale shun it. It's being sold by a company with a bad reputation for selling shit hiding behind reputable companies that unfortunately don't screen the companies they contract web page space to. Now I read the fine print so to speak, if it's not sold directly by a reputable company I usually avoid it. Seagate makes lots of Enterprise Capacity HDDs, sifting through them I found a few in my price range that have been around a while, but the Exos 7E8 replaces the Constellation ES3 no longer listed as Enterprise Capacity. It looks like the Exos is the latest and greatest in that price range and will be around for at least 5 years while the Constellation is on the way out.

So why did I go through all this HDD stuff? Two reasons, an FYI if you would like to make your machines into kaiju (Japanese for giant monsters) that like Godzilla King Of The Monsters that lived from 1952 to 1992 (the new Godzilla is actually his son Minya now full grown and Shin Godzilla is another beast entirely) are built to last, and compare a known disreputable company to one even the Google search engine can't find. Now I'll bet you dollars to doughnuts this "Mega Watt" is like Mel suggested, another "Dave Made" Chicken Band moron I wouldn't trust any farther than I can throw an Iowa Class battleship!

[koØm]

Clamp on >DC< ammeter, that's a new one on me.

Me too, I find it interesting that it can determine the polarity (direction of current flow) in the DC circuit; it has a built in "Left-Hand Rule".

For those here that had Basis Electric Theory taught to them, where they were introduced to the "Left Hand Rule"? If so, is this the way you remember it?

Definition of left-hand rule

:a rule in electricity: if the thumb and first two fingers of the left hand are arranged at right angles to each other on a conductor and the hand oriented so that the first finger points in the direction of the magnetic field and the middle finger in the direction of the electric current then the thumb will point in the direction of the force on the conductor.

So, I wonder if, holding the meter in your left hand or right hand or, the orientation on any axis makes a difference in the readings? (JK)

.

[WØTKX]

It's a Hall effect sensor, dudes.


https://www.youtube.com/watch?v=QMsuv9PadpY


https://youtu.be/v1ZaUt5P8qo

[kb2vxa]

There is another left hand rule I learned working in a TV repair shop. Remember TV repair shops? Since most people are right handed it applies, but for a few southpaws it becomes the right hand rule. When probing live circuits put your left hand in your pocket. Look pal, I'm not putting my hand on a conductor for love or money! That is unless the conductor is that sweet young thing in uniform I met aboard a train. This monkey boy is laughing because he can't figure out how to figure out which way the magnetic field is pointing the way you have your hand configured. The way I learned it in grade school is curl your fingers and stick out your thumb. With a left hand wind on a coil the thumb is north. Do it with your right hand and your thumb points south.

I first heard of the Hall effect when I built my first computer, the DC fans were called Hall Effect fans. Now they're called brushless motor fans or simply brushless fans. Everything is getting dumbed down including me, now I can't figure out why they want me to blow the dust out with expensive "canned air" when my 2" paint brush never runs out of air.

Ah, the good old AC clamp on ammeter, the heart of which is a split core current transformer. As an aside, you may have seen high current KWH meters at an industrial service entrance and wondered what's in that big steel box. For each 3 phase circuit there are 3 current transformers, the voltage windings are across the phases so they can calculate volts times amps over time. Those current transformers are closed core, simple toroid cores with many fine wire windings and load resistors across them. When just measuring amps a full wave bridge rectifier and DC microammeter calibrated in amps is the readout. I dared not disassemble the company's clamp on meter, so my best guess is scales are changed by changing load resistors. These days like everything else they just had to complicate them with digital readouts and stupidize them at the same time. They used to be clamp on meters, now they're clamp meters in case you want to measure clamps.

Just call me Professor Retro........

[WØTKX]

Use the clamps!

https://theinfosphere.org/images/1/17/Clamps.png

[n2ize]

"Dave-made, Dave-made, Dave-made".......


The fact that the company's advertisements are directed at "Ham Radio" (not Amateur Radio) and list "CB Radio" on it's front page tells the whole story; a D.C. power supply that delivers 15 volts direct current at 400 amperes (6.0 Kw!); good to power a "128 pill" 12 volt bipolar transistor RF amplifier.

How does that look on the primary side of the transformer, *if* this PSU was 100% efficient (it's not), it would pull 27 amps on a 220 volt A.C. circuit (234 vac in reality but, round numbers are easier).

Towards the end of the page, he misspells "Reviews" and his "Reveiws" come from the WWDX free-band web site.

Look harder, you can do better if you want to.

As soon as I saw this I was thinking "DAVE MADE". :)

[n2ize]

Can't speak directly to them myself, but I do run old server supplies at my place for HF. Set to 13.8v, 82A max per unit as well as a 5v terminal. Bought these for $20 each about 3 years ago used. Kinda reminded me of those.

Sorry I'm not more help.

On edit - HP branded server supplies, cycled out for age I'm sure. First learned about them from a friend into RC stuff. Apparently that demographic uses them to charge batteries.

If they are using them to charge up large Lithium Polymer batteries I sure as hell hope they are being careful and know what the heck they are doing. LiPO's tend to be extremely tempermental, especially during charging where they can produce one hell of an awesome and intense conflagration.

[KD8TUT]

If they are using them to charge up large Lithium Polymer batteries I sure as hell hope they are being careful and know what the heck they are doing. LiPO's tend to be extremely tempermental, especially during charging where they can produce one hell of an awesome and intense conflagration.

They're all a bit temperamental. Although the Lithium Manganese can be forgiving.

[koØm]

The way I learned it in grade school is curl your fingers and stick out your thumb. With a left hand wind on a coil the thumb is north. Do it with your right hand and your thumb points south.

...


Just call me Professor Retro........

I am left handed and, I used to work for this old fellow who was right handed; dude would have a conniption fit every time (almost daily - multiple times) when I would wind a Tank Coil by hand. I would grab the stock in my left hand and, form the coil in a clock-wise motion with my right hand. According to him, I was supposed to hold the stock in my right hand and form the coil in a counter-clockwise direction with my left hand - we "fought" daily.

[KD8TUT]

Thanks guys.. I was almost seduced.

Just remembered- a friend of mine who owns the local ham radio store has one I think. I'll pop in this weekend and throw a scope on it to see.

[KG4CGC]

If they are using them to charge up large Lithium Polymer batteries I sure as hell hope they are being careful and know what the heck they are doing. LiPO's tend to be extremely tempermental, especially during charging where they can produce one hell of an awesome and intense conflagration.

Hello, John. What are you using LiPo's for?