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Author Topic: Surge Protection  (Read 3406 times)
JS6TMW
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Posts: 1181




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« Reply #15 on: September 07, 2017, 06:25:16 AM »

Belt and suspenders! I learned a lesson Sunday night when a sudden electrical storm hit the neighborhood while I was out to dinner. I haven't talked to the neighbors but I believe there was a direct strike on a nearby power pylon that sent a big surge down right through my Ace Hardware "surge protectors" (ha!). It took out one USB port on my desk PC, which actually runs off a battery like a laptop but might have gotten a surge from a powered digital interface. It blew the voltage regulators and a logic chip in my keyer, which I always leave on, rather spectacularly as the pieces of one regulator fell out when I opened it. And there was also non-power line damage from I guess induced HV on the antenna that blew the diodes in my tuner's SWR coupler.

I got off cheap because no damage to my transceivers, and nothing caught fire.

Shopping for protection now!

Steve in Okinawa
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WA1RNE
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« Reply #16 on: September 07, 2017, 09:44:52 AM »

Quote
Quote from: W4OEQ on Yesterday at 11:04:09 AM

One respondent suggested using a backup 12vdc battery in parallel with the TenTec external 12vdc supply.  Had not previously considered this approach.


That is a fine approach.

Some 12VDC supplies will die horrible deaths if they are turned off or AC power removed while charging a battery.

Some supplies handle this situation fine, others need a protection diode.

 It's not just when the supply is turned off - you must use isolation rectifiers in series with the power supply and the battery. A 13.8 Vdc supply is an uncontrolled DC source which will be bad news for the battery. I would use some high current Schottky rectifiers to keep the forward voltage drop as low as possible.


 ...WA1RNE
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W6EM
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Posts: 1642




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« Reply #17 on: September 07, 2017, 04:42:27 PM »

......

If it were me, I sure would try a UPS (one that also filters and "conditions" the AC line) first............
Most of them do.
Quote
 A whole house surge protector is another matter entirely, but well worth the cost and time to install it (which is not much if you are comfortable working in an electrical panel).

And, if your incoming neutral ever opens, a guaranteed fire source as it unsuccessfully tries to clamp continuous overvoltage.  For any who must have one to feel safe, make sure it's on the load side of main breakers so that if it ultimately faults, it will trip the main.
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KD8IIC
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Posts: 648




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« Reply #18 on: September 07, 2017, 08:25:49 PM »

  Awfully doomy-gloomy sounding about running a battery in parallel off a 12vdc regulated power supply (?)
  I'm doing so using a Samelex and an SLA battery with zero trouble. On-Off no trouble yet (?)
  Maybe I'm living right or something, I dunno.
  Anyway do whatever you want.
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N8EKT
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Posts: 588




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« Reply #19 on: September 08, 2017, 04:24:24 PM »

Just pick up a UPS at your local Staples

A UPS will provide both surge protection and power
interruption protection
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KC2MMI
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« Reply #20 on: September 09, 2017, 06:21:23 PM »

Ages ago, pre-internet, author Jerry Pournelle used to write a column in Byte Magazine (computers) called "Chaos Manor", referring to his home and office. One month was devoted to the aftereffects when a car did indeed crash into a pole, which also happened to bring a 10kv power line down into the residence drop lines and his home.

Fried the refrigerator, a number of fluorescent lights, computer equipment, a number of other things. A UPS won't help in that situation (and UPS batteries rarely last 4 years, they're an ongoing expense) but a "whole house" surge protector, installed on your main breaker box or power entry, WILL stop the surges and spikes.

If you own the house...consider that even if you paid an electrician to come out and do the job (since it installs to the mains box) it is still going to be way cheaper than replacing any one appliance you own. And folks like GE say that power spikes and surges kill more major appliances than any other single cause.

A UPS is nice, for a number of reasons, but it won't protect a whole lot.

A surge protector should also have an idiot light on it, which either goes on or off to indicate when the surge protector eventually has worn out and needs replacing. (Yeah, they don't last forever.)
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WD4CHP
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Posts: 198




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« Reply #21 on: September 10, 2017, 08:34:48 AM »

I use a hefty UPS on my entertainment equipment and another the same size for my ham shack.

As I remember, they were both about $125 each. that was a few years ago.

I have replaced the batteries in one just once.

They use 2 SLA's in series.
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W6EM
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Posts: 1642




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« Reply #22 on: September 10, 2017, 09:34:45 AM »

.......
Fried the refrigerator, a number of fluorescent lights, computer equipment, a number of other things. A UPS won't help in that situation (and UPS batteries rarely last 4 years, they're an ongoing expense) but a "whole house" surge protector, installed on your main breaker box or power entry, WILL stop the surges and spikes.
In the particular example, or in the case of a direct lightning strike to an overhead service, IT WON'T!!!  Distribution primary lines have enough fault energy to blow even a distibution-class LV surge arrester to smithereans.  5 to 15kV at thousands of amperes momentarily is way beyond the Joule rating of such devices.  And, like I said, make sure, if you decide to have an electrician install one, that is is on the LOAD SIDE of main breakers in the event of an MOV short.  These devices are useful for incoming transients only, not direct-contact high voltage events or direct lightning strikes.
Quote
If you own the house...consider that even if you paid an electrician to come out and do the job (since it installs to the mains box) it is still going to be way cheaper than replacing any one appliance you own. And folks like GE say that power spikes and surges kill more major appliances than any other single cause.
  Yes, with all of the electronic controls in today's refrigerators, washing machines, kitchen ranges and dryers, GE's comments are accurate.  But, it's spikes, folks, not direct contact, that are mostly to blame.
Quote
A UPS is nice, for a number of reasons, but it won't protect a whole lot.

A surge protector should also have an idiot light on it, which either goes on or off to indicate when the surge protector eventually has worn out and needs replacing. (Yeah, they don't last forever.)
Yes, this is true.  UPSs are usually for single devices or related appliances like a computer, router and modem.  If an MOV operates and fails continuously shorted, no problem, other than replacement.  However, if burnt open, well, no protection and you won't know it.  So, maybe not so idiotic after all to have lights on the MOV devices or protector strips.....
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W6EM
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« Reply #23 on: September 10, 2017, 09:58:01 AM »

Have you considered using a relay to power your equipment / bench / shack and if there is a brownout or drop out, the power is off and you can reset it when you feel the power is stable again.  The blink is what causes A/C compressors to fail, in my 38 years running a HVAC company the failures were due to the reclosing  of the breakers in rapid succession.  like going from 60 MPH to zero and back to 60 MPH in your car, a terrific stress.

Good analogy of what happens when a utility recloser "recloses" multiple times.  Tree branches or loose overhead hardware can produce multiple successive openings and closings.  Reclosers typically will have one or two "fast-time" reclosures within 2 to 5 seconds after the initial interruption followed by a longer wait time of maybe 15 seconds.  Why?  So that the "smart" breaker characteristics can be changed to allow other devices, mostly link-fuses, to blow out that are beyond the recloser and close back in to see if the short has been removed.  This is done to re-establish power to as many customers as is possible and isolate the problem(s).

And, a very good idea about using a "seal-in" contact AC relay ahead of your equipment to drop out until manually reset.  In Tom's case, he'd lose control power to the linear (if the filaments and control power are separated from the 240V source and powered at 120V) and it wouldn't be bothered too much by its HV sequencing.  You can find surplus motor controller/starter relays (A NEMA-0 or 1 would work on 15A circuits) that have two or three high current main contacts and a fourth set of smaller control contacts. The fourth set of control contacts are usually placed in series with its coil.  By putting a push-button switch across the control contacts, that will allow them to close and "seal-in."  And, a normally-closed push-button in series with the contacts will allow manual shut off by opening the coil circuit.  Try to find one where the relay coil voltage is 120V to avoid having to add a control power transformer as well.  But, 24VAC coil voltage is more typical.
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W6EM
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Posts: 1642




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« Reply #24 on: September 10, 2017, 02:09:57 PM »

You could also use a 2-pole contactor, which would be much cheaper so long as the coil voltage is 120VAC.  Run the switched leg of the coil from a contactor output contact, then the push button switches in that leg to the coil across the NO contact to the first high side contact.  The other coil contact to the high side opposite incoming leg to the contactor.

Surplus Sales of Nebraska has some 35A DPST contactors with 120VAC coils for $10 each.
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AD4U
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« Reply #25 on: September 11, 2017, 08:01:15 AM »

Another idea is a SOLA fero-resonant constant voltage transformer. Many "newies" have never heard of them. I bought 4 of them at a hamfest for $25 each. A new one will cost many hundred $$$$. They are rated at 1000 VA (1000 watts) and they weigh around 75-100 pounds each. They are "old tech" but they work. I have one at each of my repeater sites where we get a lot of spikes etc. Since 1989 I have never has a spike problem at any of the repeater sites.

For me - I rather have a 75-100 pound lump of iron stopping spikes than a MOV that weighs a few grams.

Dick AD4U

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AC5UP
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Posts: 4413




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« Reply #26 on: September 11, 2017, 04:22:24 PM »

I have a large SOLA constant voltage transformer I picked up many moon ago that was used for a few days and hasn't been visited by Reddy Kilowatt since.

They hum.  They run hot.  The dynamic voltage regulation goes straight to hell if you put a 'bouncy' load on them thanks to over and undershoot on peaks.  With a stable load near the design limit of the transformer they have some value and will run reasonably efficiently, but at lighter loads they throw a lot of heat and that's a deal breaker for me.  Heat = wasted watts = wasted money.   Especially in a 24/7 application.  Even more weird is if you add something like a desk lamp to pre-load the output against moments of not enough load...  Back in the days of incandescent lighting the flicker was a big clue-by-four the transformer wasn't an upgrade...........  Tongue
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