Re: Lightning - funny how we're not seeing him any more
- From: "Michael W. Ryder" <_mwryder@xxxxxxxxxxxxxxxx>
- Date: Sun, 01 May 2005 23:41:58 GMT
w_tom wrote:
I referred to lurkers: people who read and don't participate. What was posted in reply to Leythos is only for their benefit.
Now for a typical plug-in UPS. It claims protection from two of five types of power problems - blackouts and extreme brownouts. Neither will damage properly constructed electronic hardware. As noted, other electrical problems are better solved elsewhere and by other devices. For example, a modest brownout where incandescent bulbs dim to 50% intensity: a problem made completely irrelevant by 'protection' already inside a minimally acceptable computer power supply. Even Intel specs make this obvious. A computer that does not power up everything even when lights are only at 50% intensity violates even Intel power supply requirements.
Just because Intel (or Microsoft) makes some proclamation that from this day forth all things will be done this way, does not mean that they are. That is why additional add on protection is needed.
For transient protection: single point earth ground. A solution located elsewhere. Anything additional is effective only if a transient is connected less than 10 feet to that earth ground. Furthermore, a power cord 'isolator' does not exist. The green safety ground wire makes such isolation impossible.
Grounds are only as effective as the surroundings. They probably work much better in Florida than here in Las Vegas. Even though our building has the necessary ground stakes, etc. does not mean they work as well as the same in a wetter climate. The isolator I was talking about is much like a very large choke to cut down the "noise" in the power signal.
As for ripple, well, a protector is not for such trivial voltages. On 120 volt service, the protect does zilch until that 'ripple' increases to 300+ volts. 300+ volts is far above 'ripple' voltages. Ripple being variations of single digit or tens of volts. But then, this 'ripple' must be eliminated in any minimally acceptable power supply. An expression carefully worded because many 'clone' computers don't have minimally acceptable power supplies. A problem created by many computer assemblers who don't even have basic electrical knowledge.
Of course, the numbers posted above should even be provided
in specs for those products and in corresponding standards. Above concepts are so basic as to be common knowledge among
those with basic technical experience. Those numbers, such as
let-through voltage and normal operating voltage limits, are
even printed on the devices. A messenger need not have any
credibility because those are numbers required to be printed
on the corresponding appliance or protector.
So what does a UPS 'clean'? What does it do? The plug-in UPS connects computer directly to AC mains when not in power supply mode. In battery backup mode, plug-in UPS exposes computer to some of the 'dirtiest' electricity. For example, a UPS in battery backup mode creates a "modified sine wave" 120 volt AC that is ... two 200 volt square waves with up to a 270 volt spike between those square waves. Is that a sine wave? Yes. A modified sine wave.
So where is this 'clean' electricity? That 'dirty' battery backup electricity is still more than clean enough for computers.
Again, the plug-in UPS outputs a 'clean' sine wave when not in battery backup mode. Why? It connects computer directly to AC mains. You can see this on any oscilloscope. Again, you are expected not to take my word for it. You are expected to confirm this yourself. Numbers were provided so that you can even see this yourself.
Other more expensive UPSes do additional functions. A line interactive UPS would cost $500+. A serious UPS (that even provides transient protection) is a building wide system installed back at the breaker box (with a less than 10 foot connection to earth ground). If you have $25,000 of disk drives, then you probably has a building wide UPS that includes many times more functions than found in a plug-in protector. For example, that building wide UPS may even address harmonic problems. No plug-in UPS even mentions such solutions. Your solution would not be a $100 'computer grade' UPS. Computer grade? It can output a modified sine wave that may harm electric motors but is sufficient to power computers. Why? Because computers are more resilient.
The UPS our company went to was a full time 4KVA system. Once it was installed we never had another equipment failure. So obviously the UPS did its job. One that grounds, etc. were not able to do. I'm not saying that our solution was for everyone, but am pointing out that relying on just one solution is not an answer either.
Sidebar: we were trying to remember the vacuum tubes used in virtually all AM radios. We remembered 35W4 and 50C5. Do you remember the other three vacuum tube part numbers for the RF amp, IF amp, and detector?
"Michael W. Ryder" wrote:
I don't know if you are referring to me as the "lurker" or not, but I have yet to see any thing in your posts that I would trust by itself. Trusting in only one form of protection is like protecting your house with a guard dog. Yes, it might work a lot of the time, but there are times when locks or alarms are also prudent. My own experiences (over 40 years with electronics starting with tubes and mechanical relays) is that a UPS has its place. It is not the only form of protection, but neither is a whole house ground, or an isolator. Our company had both of those installed by electricians (some of who worked with the major Strip hotels) and these devices only alleviated part of the power "ripple" we were seeing. A UPS was also necessary to clean up the power enough that the fragile electronics (discrete transistors) on the $25,000+ disk drives were not damaged.
This is the question a lurker must ask. Will you believe the electronic salesman who lied about an EE degree and who fears to even post those UPS specs? Or the EE who was doing this stuff before Leythos even existed? The engineer who even designed some of thise stuff, who first learned why things fail by replacing transistors, and who built electronic protection circuits says Leythos is lying. That is the extent of my personal insult vocabulary. Leythos lies. When caught in a lie, he then used personal insults to accuse the other. This post not to change Leythos mind. That is impossible. This post again to warn the lurker about outright liars such a Leythos - who even lied about having an EE degree and who will not even apologize for that lie.
And yet, I have Never seen any proof offered by you as to your qualifications. Usually when I make a choice I listen to all sides of the question, regardless of the qualifications of the proponents, and then make my choice.
.
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