power supply



How does that protect infrastructure -- or the motor?
It does narrow your losses to only the motor, but it would take one HOG of an M/G set to run my shop, and cost me yet another 30-40% in power.
LLoyd
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The real isolation method is the flywheel method. Electrical to mechanical that doesn't change with fluctuations.
AC mains drive massive multi-ton rock that spins. On that shaft is a AC (generator) alternator. It generates the AC in single or three phase. If the external AC shuts down, the rock keeps turning. It turns for a long time without input power. So brown outs and twinkles are never seen on the real load because the rock absorbs small and large changes.
Cray Research used them for their buildings. Massive spinning disks of rock.
Martin - been there, seen it.
On 3/10/2015 1:33 PM, Lloyd E. Sponenburgh wrote:

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    Well ... our lab had something similar to make sure that the fume hoods would not suddenly stop when some rather toxic gasses were in use there. It also protected the rest of the building, too.
    But -- it was not a separate motor and generator. Instead, a *big* permanent magnet rotor three-phase motor kept the flywheel (steel, not rock in this case) spinning. About 4' diameter by about 8" thick, IIRC.
    On the other side of the flywheel was a flexible coupling, an electro-magnetic clutch (brake assembly from a B-58 I believe) and a big Detroit Diesel.
    A cabinet of electronics monitored the power. If the frequency or voltage drifted out of spec, the clutch was allowed to transmit torque, and the flywheel started the Diesel *right* *now*. In the meanswhile, the permanent magnet rotor three phase motor became a generator, and kept the building going. The flywheel for a little while, and then the Diesel
    Now there were three *big* breakers on a panel. One from line to the motor, one from the motor to the load, and one from line to the load. Once, someone switched off the line to motor breaker, and then switched it back on -- without the benefit of the electronics in the cabinet. Thus it connected about the time the phase had drifted 180 degrees. It drew a *lot* of current, and blew out the fuse on the pole pig, and another closer to the substation on post. :-)
    Enjoy,         DoN.
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On Wednesday, March 11, 2015 at 11:37:05 PM UTC-4, DoN. Nichols wrote:

And at demo time, those breakers and that 500 wire and bus bars aren't bad for spending change.
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The object of the Cray way was smooth power all of the time. If there was time to power down ok. But spikes and sags were not wanted when measuring signals and building monster machines.
Yours was a UPS of sorts as long as the 'oil' was flowing.
Martin
On 3/11/2015 10:37 PM, DoN. Nichols wrote:

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typed in rec.crafts.metalworking the following:

    Now now, don't be hard on him. It isn't that he is unlikely to have completed 7th grade, but that his education ceased about then. After all, it is possible for one to "graduate" from college no smarter than when one started - possibly even less so. So he recalls those years he spent as a college sophomore as the best years of his life, at least as far as he can recall. -- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."
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Pyotr, that was good! I had to read it twice to 'get it'!
Lloyd
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> on Sun, 08 Mar 2015 20:19:37 -0500 typed in rec.crafts.metalworking the following:

    Tweren't just the sixties which, if you remember them - you really weren't fully experiencing them. -- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."
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On Sunday, March 8, 2015 at 9:06:22 PM UTC-4, pyotr filipivich wrote:

Wow, I see the 7th grade reminded you of something that was probably always on your mind. You are too, too funny. Are you into video games or something?
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On Sunday, March 8, 2015 at 8:22:14 AM UTC-4, Leon Fisk wrote in rec.crafts.metalworking:

Leon Fisk
8:22 AM (2 hours ago)
On Sat, 07 Mar 2015 22:55:42 -0500
<snip> >If the tower was not properly grounded lightning will cause damage.

Psst... John, wake up, you're dreaming...
I worked in two-way radio communication most of my career. Several of the towers I serviced equipment at were grounded to R56 spec, which was very ambitious and the best at the time. The equipment still took hits that caused considerable damage...
And other towers that had little to no grounding and got hit regularly, had very little equipment damage. Go figure...
Maybe our lightning had more oomph than your lightning ;-)

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Leon Fisk wrote:

I guess you never learned that in a lightning prone system always use a DC grounded antenna system a folded dipole for example otherwise the lightning takes a partial path through the center conductor of the coax and travels to the transmitter blowing your relay.
Several of the towers I serviced equipment at were grounded to R56 spec, which was

I got out of the business when Micors came out. I went into aviation electronics. I had worked on many HT 180's, Twin V 44 UHF and all the other stuff Motorola made. I maintained equipment on every tall building in NYC including the Empire state bldg. Chrysler building Pan Am building, and many others as well as many in NJ. so I do have a little experience with lightning hitting antennas.
It all comes down to having a place for lightning to go directly to ground so it doesn't take stray paths into the the equipment blowing something out.
John
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On Saturday, March 7, 2015 at 10:55:46 PM UTC-5, John wrote:

ARTICLE 280 Surge Arresters
I. General
280.1 Scope. This Article covers the installation and connection requiremen ts for surge arresters that are permanently installed on the line side of s ervice equipment.
Author's Comment: According to Article 100, Service Equipment is the necess ary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s), connected to the load end of service conductors, and intended to constitute the main control and cutoff of the supply.
280.2. Definition. Surge Arrester. A protective device for limiting surge voltages by dischar ging or bypassing surge current, and it also prevents continued flow of fol low current while remaining capable of repeating these functions.
280.3 Number Required. Where used, a surge arrester shall be connected to each ungrounded conduct or of the system and a single surge arrester shall be permitted to protect all of the line conductors.
280.4 Surge Arrester Selection. (A) Circuits of Less Than 1000 Volts. The rating of the surge arrester sha ll be equal to or greater than the maximum phase-to-ground voltage at the p oint of connection.
Surge arresters installed on circuits of less than 1000 volts shall be list ed for the purpose.
FPN No. 2: See the manufacturer's application rules for the selection of an arrester for a particular application.
II. Installation
280.11 Location. Surge arresters shall be permitted to be located indoors or outdoors.
280.12 Routing of Connections. The conductors for the surge arresters shall not be longer than necessary, and unnecessary bends should be avoided.
III. Connecting Surge Arresters
280.21 Installed at Service Equipment. The grounding conductor for the arrester shall be connected to one of the following locations: (1) Grounded (neutral) service conductor. (2) Grounding electrode conductor. (3) Grounding electrode for the service. (4) Equipment grounding terminal in the service equipment.
280.22 Installed on the Load Side Service Equipment. A surge arrester shall be permitted to be connected between any two conduc tors - ungrounded conductor(s), grounded conductor and grounding conductor.
280.25 Grounding. Grounding conductors for surge arresters shall not be run in metal enclosu res unless the metal raceway is bonded to both ends to the grounding conduc tor.
Article 285 - Transient Voltage Surge Suppressors (TVSSs)
I. General
285.1 Scope. This Article covers the installation and connection requiremen ts for TVSSs that are permanently installed on premises wiring systems. Fig ure 285-1 285-01 cc285-01.cdr
Author's Comment: The scope of Article 285 applies to devices that are list ed as TVSS devices. It does not apply to devices that incorporate a TVSS de vice, such as a cord-and-plug connected TVSS unit, a receptacle, or an appl iance that has integral TVSS protection. For more information about TVSS de vices, visit www.mikeholt.com/Powerquality/Powerquality.htm
285.2 Definition Transient Voltage Surge Suppressor (TVSS). A protective device for limitin g transient voltages by diverting or limiting surge current; it also preven ts continued flow of follow current while remaining capable of repeating th ese functions.
285.3 Uses Not Permitted. A TVSS shall not be used for: (1) Circuits exceeding 600 volts (2) Ungrounded electrical systems (3) Where the rating of the TVSS is less than the maximum phase-to-ground voltage at the point of connection.
FPN: For further information on TVSSs, see NEMA LS 1-1992, Standard for Low Voltage Surge Suppression Devices. The selection of a properly rated TVSS is based on criteria such as maximum continuous operating voltage and the m agnitude and duration of overvoltages at the suppressor location.
285.4 Number Required. Where used, a surge arrester shall be connected to each ungrounded conduct or of the system.
285.5 Listing. A TVSS shall be a listed device in accordance with UL 1449.
285.6 Short Circuit Current Rating. TVSS devices shall be marked with their short circuit current rating, and they shall not be installed where the available fault current is in excess of that rating.
WARNING: TVSS devices of the series type are susceptible to high fault curr ents if located near service equipment, and a hazard would be present if th e device rating is less than the available fault current.
II. Installation
285.11 Location. TVSSs shall be permitted to be located indoors or outdoors.
285.12 Routing of Connections. The conductors for the TVSS shall not be any longer than necessary and unnecessary bends shall be avoided.
III. Connecting Transient Voltage Surge Suppressors
285.21 Connection. Where a TVSS is installed, it shall be connected as foll ows: (A) Location. (1) Service Supplied Building or Structure. A TVSS can be connected anywhe re on the premises wiring system, but not on the line side of the service d isconnect overcurrent device. Figure 285-2 285-21A1 cc285-02.cdr
Author's Comment: Care must be taken to ensure that no more than one conduc tor terminates on a terminal, unless the terminal is identified otherwise [ 110.14(A)].
Exception: A TVSS device listed as a surge arrester in accordance with 280. 4(A) can be connected to the line side of the service overcurrent device.
Author's Comment: TVSSs are listed to be located only on the load side of s ervice equipment. TVSS devices cannot be installed on the line side of the building or structure overcurrent device because of the concern that they m ight be exposed to lightning-induced surges.
(2) Feeder Supplied Building or Structure. A TVSS can be connected anywhere on the premises wiring system, but not on the line side of the building or structure disconnect overcurrent device.
(3) Separately Derived System. A TVSS can be connected anywhere on the prem ises wiring of the separately derived system, but not on the line side of t he separately derived system overcurrent device.
(B) Conductor Size. Line and ground connecting conductors shall not be smal ler than 14 AWG copper.
(C) Connection Between Conductors. A TVSS shall be permitted to be connecte d between any two conductors - ungrounded conductor(s), grounded conductor and grounding conductor.
285.25 Grounding. Grounding conductors for surge arresters shall not be run in metal enclosu res unless the metal raceway is bonded to both ends to the grounding conduc tor.
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I had a friend in the Dallas area that had a heavy hit - very strong - come down and burn the side of his house at the utility lead. It killed every electrical or electronic item that was attached to the wall or power...
His insurance man laughed at first - until he started making a list.
Martin
On 3/6/2015 12:08 PM, Leon Fisk wrote:

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On Fri, 06 Mar 2015 22:58:04 -0600, Martin Eastburn

That's why I LOVE underground electrical distribution. Storms don't take down the lines, and lighting can't find the wires to deliver a direct hit. I use on-line (dual conversion) UPS for my sensitive electronics (computers)
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On Saturday, March 7, 2015 at 1:10:45 AM UTC-5, Clare wrote:

Bullcrap. There are plenty of times that underground cables were struck by lighting, too. Lloyd should just tell the power company to put surge arrestors in before service is supplied to the property.
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snipped-for-privacy@snyder.on.ca wrote:

I had a strike on my barn, years ago. The electric lines ran underground, to the power pole, near the house. It got into the phone line, and vaporized the wire all the way to the street, a mile away. It destroyed the SLIC in the pedestal, and made it over five miles into the CO, in town. It also damaged a computer monitor that had the cables disconnected, and wrapped around the base of the monitor. It fried the C-band TV system, a TV, a stereo and one of my computers.
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On Mon, 16 Mar 2015 14:41:39 -0400, "Michael A. Terrell"

The closest "above ground" electrical wire to my place is almost 2 miles away, with half a dozen transformers in vaults between here and there to "catch" the surge and dump it to ground before it gets here. The dual conversion UPS looks after what's left. (we are in Ontario's "thunder alley" so we get lot's of lightning storms.)
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snipped-for-privacy@snyder.on.ca wrote:

Do you have a 300 foot tower to deal with? :)
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On Thu, 19 Mar 2015 22:50:48 -0400, "Michael A. Terrell"

Where in my description would that fit in??? Yes, the high tension wiring is on tall steel towers. The street lamps are on steel or re-enforced concrete poles. There are cell and radio towers around - but none of them have any influence on our local power distribution, phone, or cable.
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snipped-for-privacy@snyder.on.ca wrote:

That was to do with the strike at the CATV headend. :) BTW, that service was underground.
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