Dual power paths and single-cord equipment

Protecting your data center against power failure is crucial to providing maximum availability. Power loss or poor power quality is a major contributor to data center server down time. This task takes more than simply having UPS and a backup power source, such as a generator. Dual Power Paths: A Crucial Element in a High-Availability Data Center article tells that in in high availability environments, a common way to provide redundancy is to supply two independent power paths to each piece of computing equipment. All Dual Feeds Are Not Created Equal white paper explains the classification system for data center power feeds and provides the pros/cons of each configuration.

The use of dual power path architecture in combination with IT equipment with dual power supplies and power cords is an industry best-practice. Data centers designed and built utilizing Tier IV requirements are by definition “concurrently maintainable,” which means any system or component in the data center may be shut down for maintenance or may fail without affecting the delivery of services to the end user. In the case of a dual-powered data center, this typically is achieved by delivering at least two power circuits to each cabinet, one from the A power source and one from the B power source. The equipment accepts the two power feeds via independent, parallel power supplies that are sized such that the equipment will continue to operate with only one power path. To make this work the equipment to be powered need to have Redundant Power Supplies.

Redundant Power Supplies are one advanced feature available on high-end server machines. In essence, this is a power supply that actually includes two (or more) units within it, each of which is capable of powering the entire system by itself. If for some reason there is a failure in one of the units, the other one will seamlessly take over to prevent the loss of power to the PC. You can usually even replace the damaged unit without taking the machine down.

Design Tips for the Dual-Powered Data Center and Four A-B Design Failures to Avoid in the Dual-Powered Data Centerarticles gives some more tips how to design dual power paths. You need to be careful in designing dual-powered data center. Failure to properly design, size and implement dual power infrastructure at the cabinet may lead to breaker trip during restart (starting current of many computing devices and storage systems could easily exceed 200% of the running load for some time). You need to have enough spare capacity, but on the other hand failing to fully load power circuits to their rated capacity may not result in downtime but may drive power subscription costs higher than necessary. Proper power planning and budgeting involves loading every circuit to the proper rated capacity while respecting safety margins.

For dual power paths approach to be effective, you’ve got to meet two requirements:

  • The protected equipment must support dual power feeds and operate with one feed faulted.
  • The loading of breakers within each power path must always be less than 50% of trip rating during normal conditions, so the breaker doesn’t trip if the alternate path has to take on the full load.

Meeting these two requirements can be a challenge. Especially because some computing and networking equipment is only available with a single power cord. It’s good design principle to disallow the use of single power cord computer devices in a high-availability data center environment, but there are case where those can’t be avoided. For example some network products or legacy servers may only have single power supplies.

One good way to over-come single power input equipment problem is to use an Automatic Transfer Switch (ATS), which generates a single feed from two inputs. These single power supply devices can still be used with reliability by utilizing automatic transfer switches. Redundant Power Supply article has the following picture to show the use if automatic switch.

Powering single-cord equipment in dual path data center environments article tells about a new white paper from APC-Schneider Electric addresses the concern of powering single-corded equipment in dual path data center environments. However, equipment with a single power supply introduces a weakness into an otherwise highly available data center. Transfer switches are often used to enhance single-corded equipment availability by providing the benefits of redundant utility paths. You need to understand the use of power transfer switches well because there are several possible configurations how to use them, with their pros and cons.

Powering Single-corded Equipment in a Dual Path Environment white paper goes on to describe three fundamental approaches to powering single-corded equipment in a dual path data center environment. There are a number of options for integrating single-corded devices into a high availability dual path data center. Powering Single-corded Equipment in a Dual Path Environment paper explains the differences between the various options and provides a guide to selecting the appropriate approach. The conclusion is that Power availability to the single-corded equipment below 10 kVA is optimized by bringing utility redundancy directly to the rack. This can be done by using a rack mount static transfer switch or a rack mount ATS, and the optimal solution is a rack mount ATS.

A well designed adaptable rack enclosure power system would be able to support a single or dual path environment or a hybrid of both single and dual equipment. Automatic Transfer Switch (ATS) used in data center is typically rack mountable and occupy 1U or rack unit of space. They feature dual input cords and are able to switch from one power circuit to the other in a few micro seconds when power failure is detected on one of the input leads.

The idea to write about this topic to this blog came to me after reading Powering Single-corded Equipment in a Dual Path Environment white paper.

131 Comments

  1. Tomi Engdahl says:

    Your questions answered: Critical power: Combined heat and power systems
    Questions not covered during the March 7, 2019, webcast are addressed here.
    https://www.csemag.com/articles/your-questions-answered-critical-power-combined-heat-and-power-systems/

    Reply
  2. Tomi Engdahl says:

    Zonit micro ATS and z-PDU for “5 seconds to single-, split-single, and/or 3-phase power”
    https://www.youtube.com/watch?v=l_Cozr4Nq5o

    We manufacturer products to solve real point problems in data centers, facility control systems, and wiring closets. In this animation, Zonit shows our zPDS and micro Automatic transfer switch providing dual A-B power for single power corded devices. We also show the zPDS which is a top-of-stack PDU providing 10 seconds to a automatic phase balanced single, split-single, and or 3-phase circuit.

    Reply
  3. Tomi Engdahl says:

    Zonit’s uATS (Micro Automatic Transfer Switch) description of LED feedback
    https://www.youtube.com/watch?v=-cNx_L02MHQ

    The micro ATS (µATS™) provides dual-power path redundancy to devices with one power supply and power cord. The Zonit μATS™ takes no rack space, and provides redundant “A-B” power to single-power-supply devices such as servers and routers.

    How does it work? The Zonit μATS™ plugs directly into the back of single-power-supply devices (such as servers, routers, and switches), optionally it can output via a power cord or a hydra multi-headed power cord, and it can be moved with the device for “hot moves.” It features two power cords and intelligent circuitry that monitors the power quality of the primary power source. If the primary “A-source” power quality becomes unacceptable, the Zonit μATS™ automatically switches over and draws power from the back-up “B-source,” thus keeping the device to which it’s connected up and running.

    The μATS™ is available in 120V, 12A or 208-240V, 8A models.

    Z-ATS – Micro Automatic Transfer Switch
    https://www.zonit.com/products/micro-ats

    Reply
  4. Tomi Engdahl says:

    How to Wire Auto & Manual Changeover & Transfer Switch – (1 & 3 Phase)
    https://www.electricaltechnology.org/2018/11/automatic-manual-changeover-transfer-switch.html

    We will show how to wire and connect single phase and three phase automatic and manual changeover and transfer switches to the home distribution board to use the backup power supply such us batteries power with UPS and inverters or generator power in case of emergency breakdown and power outage.

    Reply
  5. Tomi Engdahl says:

    How to Install a Manual Transfer Switch for a Portable Generator | Ask This Old House
    https://www.youtube.com/watch?v=GLgtFCJlVFQ

    Ask This Old House master electrician Scott Caron visits Alaska to install a portable generator with a manual transfer switch to power hardwired appliances like a well pump and heating system using unleaded gasoline.

    Reply
  6. Tomi Engdahl says:

    Budget Friendly Emergency Backup Power – Transfer Switch
    https://www.youtube.com/watch?v=EiRW6rpLxyQ

    Today I outline how my budget friendly emergency backup power system works. It includes a portable generator and a transfer switch

    Reply
  7. Tomi Engdahl says:

    Synchronizing AC generators — Part 1 (introduction and sync lamps)
    https://www.youtube.com/watch?v=RGPCIypib5Q

    We are using a pair of Delco-Remy 3-phase alternators to generate 60 Hz AC power for a miniature demonstration electrical power grid. In this video, we discuss some of the details of generator synchronization.

    Synchronizing AC generators — Part 2 (strobe light view)
    https://www.youtube.com/watch?v=sFohkp2aaU4

    We are using a pair of Delco-Remy 3-phase alternators to generate 60 Hz AC power for a miniature demonstration electrical power grid. In this video, we discuss some of the details of generator synchronization, using a stroboscope to prove two generators are spinning in-phase with each other.

    Reply
  8. Tomi Engdahl says:

    How to Run Synchronous Generators in Parallel ㅣMarine Electrician
    https://www.youtube.com/watch?v=uVTyzsCFE6I

    Most switchboards nowadays have automatic synchronization of generators

    With just a press of a button, generators can easily be paralleled
    Since automatic synchronization is a more accurate way of paralleling generators

    Joining my current ship, an ancient ship, I was lucky enough to experience to synchronize generators manually

    Reply
  9. Tomi Engdahl says:

    How to Perform a UPS Transfer in a Critical Data Center
    https://www.youtube.com/watch?v=pGthey0Q1dw

    The Markley Group demonstrates how power at a UPS in a data center is transferred without its critical loads seeing any interruption. Routinely this type of procedure is performed at One Summer Street to allow technicians to safely work on critical electrical equipment without any risk to your information. Video by Christopher Huang

    Reply
  10. Tomi Engdahl says:

    Connecting Power Supplies in Parallel
    https://www.loxone.com/enen/kb/connecting-power-supplies-parallel/

    For parallel operation of power supplies, a few technical details must be observed.

    Should a power supply be switched off or in the worst case fail, it is necessary to install a diode which protects the secondary power supply from damage caused by an opposite current flow.

    Reply
  11. Tomi Engdahl says:

    The complete design information of the project, 3 PHASE AUTOMATIC CHANGE OVER SYSTEM is out!!!, Click the link below to access it.
    https://youtu.be/Dxzs9vblFRg

    Reply
  12. Tomi Engdahl says:

    Application Note
    Basics of Ideal Diodes
    https://www.ti.com/lit/an/slvae57b/slvae57b.pdf?HQS=app-psil-psw-lm7472xq1-asset-mc-ElectronicDesign-wwe&ts=1637040689629

    Schottky diodes are widely used in power system designs to provide protection from various input supply
    fault conditions and to provide system redundancy by paralleling power supplies. Power schottky diodes are
    used in automotive power system design to provide protection from reverse battery conditions and protect
    from various automotive electrical transients. Industrial systems traditionally have employed schottky diodes to
    provide reverse polarity protection from field power supply mis-wiring and provide immunity from lightning and
    industrial surges.Commonly used industrial systems, telecommunication servers, storage, and infrastructure equipments employ
    schottky diodes to provide system redundancy or increase power capacity by ORing two or more power sources.
    However, the forward voltage drop of the schottky diodes results in significant power loss at high currents and
    increases the need for thermal management using heat sinks and a larger PCB space. Forward conduction loss
    and associated thermal management reduces efficiency and increases system cost and space. With increasing
    system power levels and need for improved power density, schottky diodes are not preferred for newer high
    performance system designs.

    Reply
  13. Tomi Engdahl says:

    Pilvi vaatii älykästä tehonsyöttöä
    https://etn.fi/index.php/tekniset-artikkelit/13164-pilvi-vaatii-aelykaestae-tehonsyoettoeae

    Kuluttajien datantarve on loputon ja sitä ruokitaan pilvipalveluilla datakeskuksissa. Pilvipalvelimien tehokas käyttö edellyttää erittäin huolellista tehonsyöttöä.

    Research and Marketsin [1] mukaan maailman datakeskusmarkkinoiden odotetaan kasvavan vuosittain 6,4 prosenttia toissavuoden 26,1 miljardista dollarista 26,1 miljardiin dollariin vuoteen 2025 mennessä. Pilvipalveluiden kysynnän kasvu lisää tarvetta parantaa suoritustehoa. Data Center Knowledgen [2] mukaan on arvioitu, että maailmanlaajuisesti datakeskukset kuluttivat vuonna 2018 tehoa 205 terawattituntia (205,000,000,000,000 W/h) vuonna 2018. Noin merkittävä tehonkulutuksen lisääntyminen antaa aihetta miettiä priorisointia suorituskyvyn ja luotettavuuden osalta.
    Pilvipalvelujen tehon muuttaminen

    Useimpia datakeskusten laitekehikkoja syötetään 220 V:n UPS-virralla, jolloin teholukemat kehikkoa kohden nousevat lähelle 100 kilowattia. Kun pidetään mielessä, että useimpien ydinprosessorien jännitearvot ovat alle 2 V, joudutaan suuria jännitetasoja muuntamaan ja jakamaan. Sen lisäksi suuret tehot tarkoittavat suuria virtamääriä, jotka pitää uudelleen reitittää mahdollisimman tehokkaasti teho- ja lämpöhäviöiden minimoimiseksi. Monilla palvelinkehikoilla on 48 V:n teholähde taustakortilla. Se toimii pääasiallisena eli primäärisyöttönä jokaiselle kehikolla olevalle palvelimelle, joihin myös viitataan palvelinlevyinä.

    Perinteisesti 48 V on ollut standardi tehonsyöttö tietoliikenteen ja verkkotekniikan infrastruktuureissa. Syynä 48 V:n valintaan on se, että yleisesti sen on ajateltu olevan suurin ihmiselle vaaraton jännite. Tyypillisesti yli 48 V:n jännitetasoja vaativien laitteiden täytyy olla kaksinkertaisesti eristettyjä ja tulee lisäksi täyttää tiukimmat turvallisuusvaatimukset.

    48 V versus 12 V

    Palvelinten 48 V:n tehonsyöttöön liittyen on kertynyt paljon keskustelua ja kokeiluja. Perinteisesti useimpien tietokoneiden ja palvelintyöasemien sisäisenä tehonsyöttönä on käytetty 12 V:n jännitetasoa. Tämä periytyy vaatimuksista, jotka juontavat juurensa aiemmin käytetyistä puolijohdeteknologioista, sekä tietokoneissa käytettävistä haihtumattoman tallennuksen kiintolevyistä, tuulettimista ja muista komponenteista.

    Yksi tapa torjua tehohäviöitä on laitekehikolle tulevan 48 V:n tehonsyötön liittäminen itse palvelimeen ja ottaa käyttöön kuormakohtaiset (POL, point-of-load) tehonmuuntimet.

    Käytettäessä 48 V:n teholähdettä saadaan sama teho kuormaan neljännesvirralla, jolloin johdintien tehohäviöt pienenevät kertoimella 16. Tämä järjestelmän tehokkuuden merkittävä parannus tuo mukanaan haasteita. 12 V:n tehoratkaisut ovat olleet optimoidut useiden piirisukupolvien käyttöön ja ovat hyötysuhteeltaan äärimmäisen tehokkaita. Suuremman jännitetason tehonsyöttö vaatii suurempaa jännitteenalennusta CPU:n jännitetasojen saavuttamiseksi, mistä seurauksena voi olla tehomuunnosasteen suorituskyvyn heikkeneminen. Lisäksi tarvitaan myös suuritehoisten piiteknologioiden käyttöönottoa, jolloin MOSFET-arkkitehtuureissa alakohtaiset resistanssit kasvavat. Tämä kasvattaa myös järjestelmäkustannuksia.

    Tehokkaimmat esitellyt kokonaisratkaisut ovat olleet 48 V – 12 V – 1 V prosessoriytimen tehonsyötön toteutuksissa. Tämä lähestymistapa sekä hyödyntää vanhoja ratkaisuja että tasoittaa jännitealenemaa, jolloin järjestelmän kokonaissuorituskyky saadaan maksimoitua.

    CPU:n ytimen tehonsyöttö

    Suurivirtaiset tasavirtatehomuuntimet on tavallisesti toteutettu monivaiheisilla topologioilla. Jokainen vaihe käsittää tyypillisesti kaksi MOSFETtiä (korkean ja matalan puolen puolisilta-konfiguraatio) ja induktorin yksittäisen jännitettä laskevan katkojan aikaansaamiseksi. Tällaiseen arkkitehtuuriin viitataan yleisesti tehoasteena. Useita vaiheita ketjutetaan toisiinsa ja ohjataan yksittäisellä älykkäällä tehonhallintapiirillä (PMIC). Jokaisen vaiheen kytkeminen täytyy porrastaa ja tarkasti ohjata kuorman asetusten, huojunnan, transienttivasteen ja sekä lähteen säteilemien että johtuneiden kohinapäästöjen optimoimiseksi.

    Tehoasteiden määrä ja kussakin asteessa kulkevan virran suuruus ovat tarkasti sovitettuja jokaisen CPU-sukupolven tarpeita vastaavasti. Markkinoilla on havaittavissa, että tarvittavien asteiden määrät ovat kasvussa ja että jokaisessa asteessa edellytetään suurempia virrantiheyksiä. Edistyneimmät monivaiheiset muuntimet voivat käsittää 16 vaihetta, jolloin jaettavan tehonsyötön kokonaismäärä ylittää helposti 1000 W.

    Älykkäät tehoasteet

    Kehittyneiden CPU-prosessorien edellyttämien äärimmäisten tehotiheyksien ”sivutuotteena” syntyy tarve aikaansaada hyvin tiukka kuorman regulointi. Edistyneet alle mikrometrin (deep sub-micron) piiteknologiat eivät siedä suuria jännitepoikkeamia tehonsyötössä eivätkä signaalipoluilla.

    Reply
  14. Tomi Engdahl says:

    ATS or Automatic Transfer Switch is a device that automatically transfers a power supply from its primary source to a backup source when it senses a failure or outage in the primary source.

    Reply
  15. Tomi Engdahl says:

    Automatic generator changeover switch (with schematic).
    https://www.youtube.com/watch?v=babtv00R-Nc

    This was a lot of fun to reverse engineer. Mainly because it’s very old-school inside. It’s an automatic changeover switch for a backup generator supply. When power fails and the generator starts, the switch will automatically transfer over to the generator. When the power returns it will switch back over to the main supply.

    The issue with the relay being energised all the time and to make it generator-priority could be addressed by simply swapping the sides the main and generator power are attached to. That way the generator would take priority in the event of a power failure and not switch back until it was turned off, and the relay would only be energised when the generator was running.

    Reply
  16. Tomi Engdahl says:

    ATS Automatic Transfer Switch Changeover
    https://www.youtube.com/watch?v=AUdNmwZaucI

    Automatic transfer switch ATS forms the interface between the gen set utility power and the consuming electrical equipment it performs three functions it monitors power sources for failure it transfers load from one power source to another.
    what is electrical changeover
    A changeover switch switches a house electricity supply from the general grid power supply to a generator system in case of power outage the changeover switch connects to the main power grid generator or alternate source and the house wiring.

    Reply
  17. Tomi Engdahl says:

    EEVblog 1500 – How an AC Automatic Transfer Switch Works
    https://www.youtube.com/watch?v=W1Q8CxL95_Y

    Automatic AC transfer switches are pretty cool devices. A look at what they do, a practical demo, teardown, and then reverse engineering to explain how it does it.
    Bonus look at how my automated home battery backup system will work.

    00:00 – Automatic AC Transfer switch
    02:05 – How I’m powering my home fridges from a battery
    06:30 – What does an AC Transfer switch do?
    09:27 – Huh? How do you do the automated battery power backup?
    12:36 – Practical AC Transfer switch demo
    15:57 – Teardown
    18:44 – Reverse Engineering Schematic
    25:46 – BONUS 2nd design teardown!

    https://www.eevblog.com/forum/blog/eevblog-1500-how-an-ac-automatic-transfer-switch-works/

    Reply
  18. Tomi Engdahl says:

    EEVblog 1500 – Automatic Transfer Switch REVERSE ENGINEERED
    https://www.youtube.com/watch?v=W1Q8CxL95_Y&t=283s

    Automatic AC transfer switches are pretty cool devices. A look at what they do, a practical demo, teardown, and then reverse engineering to explain how it does it with a direct one-to-one schematic-physical mapping.
    Bonus look at how my automated home battery backup system will work.

    00:00 – Automatic AC Transfer switch
    02:05 – How I’m powering my home fridges from a battery
    06:30 – What does an AC Transfer switch do?
    09:27 – Huh? How do you do the automated battery power backup?
    12:36 – Practical AC Transfer switch demo
    15:57 – Teardown
    18:44 – Reverse Engineering Schematic
    25:46 – BONUS 2nd design teardown!

    Forum:
    https://www.eevblog.com/forum/blog/eevblog-1500-how-an-ac-automatic-transfer-switch-works/

    Reply
  19. Tomi Engdahl says:

    Automatic generator changeover switch (with schematic).
    https://www.youtube.com/watch?v=babtv00R-Nc&t=1287s

    This was a lot of fun to reverse engineer. Mainly because it’s very old-school inside. It’s an automatic changeover switch for a backup generator supply. When power fails and the generator starts, the switch will automatically transfer over to the generator. When the power returns it will switch back over to the main supply.

    The issue with the relay being energised all the time and to make it generator-priority could be addressed by simply swapping the sides the main and generator power are attached to. That way the generator would take priority in the event of a power failure and not switch back until it was turned off, and the relay would only be energised when the generator was running.

    Reply
  20. Tomi Engdahl says:

    EEVblog 1500 – Automatic Transfer Switch REVERSE ENGINEERED
    https://www.youtube.com/watch?v=W1Q8CxL95_Y&t=370s

    Automatic AC transfer switches are pretty cool devices. A look at what they do, a practical demo, teardown, and then reverse engineering to explain how it does it with a direct one-to-one schematic-physical mapping.
    Bonus look at how my automated home battery backup system will work.

    00:00 – Automatic AC Transfer switch
    02:05 – How I’m powering my home fridges from a battery
    06:30 – What does an AC Transfer switch do?
    09:27 – Huh? How do you do the automated battery power backup?
    12:36 – Practical AC Transfer switch demo
    15:57 – Teardown
    18:44 – Reverse Engineering Schematic
    25:46 – BONUS 2nd design teardown!

    Reply
  21. Tomi Engdahl says:

    Automatic generator changeover switch (with schematic).
    https://www.youtube.com/watch?v=babtv00R-Nc&t=1334s

    Reply
  22. Tomi Engdahl says:

    eBay CJX2 industrial contactor teardown.
    https://www.youtube.com/watch?v=jqNnWa0CHw0

    I thought it would be quite interesting to take a cheap general purpose eBay contactor apart to see what the build quality is like. I’d rate this as being acceptable for prototyping and home workshop use. These contactors are available with 24v, 36v, 110v, 220v.and 380v coils.

    Teardown of an eBay 25A Solid State Relay. (SSR)
    https://www.youtube.com/watch?v=DxEhxjvifyY

    A solid state relay is an industrial component used for interfacing low voltage control signals to high current mains voltage loads.
    They sell them on eBay at a ridiculously low price, so it’s time to see what’s actually inside one of these eBay units.

    I have the exact same part from an ebay seller that I intended to use in a Kiln controller (~3KW max output).
    So after watching this I stripped mine down to reveal that it also contains the BTA12-600B, obviosuly not quite sufficient for my application.

    I have now ordered a BTA24-600B to uprate this to its original spec of 25A, at least I will now be operating its safe area.

    Reply
  23. Tomi Engdahl says:

    Dual-Locking Power Connector Prevents Accidental Disconnection
    https://www.electronicdesign.com/resources/products-of-the-week/media-gallery/21251339/electronic-design-products-of-the-week-1200v-sic-modules-duallocking-connectors?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS220922089&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R&id=21251339&slide=3

    Schaffner introduced a new series of IEC power connectors with a unique dual-locking system that keeps power cords connected and power flowing to electronics in data centers, industrial equipment, medical devices, as well as audio/broadcast equipment.

    The new IL13P-S series stands out from other parts in its portfolio by combining a pair of locking mechanisms into a single connector. This ensures compatibility with a wide range of standard non-locking C13 socket outlets including inlet filter types: IL 13, IL 13 P, and IL 19. The connector can mate with any Schaffner IEC C14/C20 inlet filter and is a simple retrofit for any IEC C14/C20 inlet.

    On the load side of the system is a compact IEC C13+ connector, while the line side is based on the company’s IEC lock C14 connector. Rated current is up to 10 A (C13 plug), up to 15 A (C13P plug), and up to 20 A (C19 plug), while the maximum pin temperature is 70°C. The locking system has a tensile force of typically 200N; flange mount filters are recommended.

    Reply
  24. Tomi Engdahl says:

    Automaattisesti varavirran varaan
    https://etn.fi/index.php/new-products/14882-automaattisesti-varavirran-varaan

    Schneider Electricin automaattisten syötönvaihtokytkimien TransferPacT-tuoteperheeseen kuuluu valikoima skaalautuvia, helposti muokattavia, suorituskyvyltään erinomaisia, älykkäitä ja kompaktin kokoisia automaattisia verkonvaihtokytkimiä. TransferPacT Automatic ATS-laite suorittaa verkonvaihdon automaattisesti ja sähköjärjestelmässä, jossa normaalin verkon lisäksi on käytössä toinen virtalähde, kuten generaattori, toinen muuntaja tai energiavarasto.

    TransferPacT Automatic sisältää kaikki tarvittavat ominaisuudet yhdessä laitteessa ja on helppo valita, asentaa ja käyttää. Laitteen toimintoja voidaan laajentaa lisämoduulien avulla esimerkiksi niin, että verkon vikatilanteessa TransferPacT antaa generaattorille käynnistyskäskyn, valvoo generaattorin käynnistymistä ja suorittaa siirron vasta kun generaattori on onnistuneesti käynnistynyt. Muita mahdollisia lisätoimintoja ovat esimerkiksi generaattorikäytöissä kuormankevennys ennen käynnistymistä tai verkonvaihdon pakko-ohjaus korkean energiatariffin takia.

    TransferPacT on IEC-60947-6-1-standardin mukainen PC-luokan automaattinen syötönvaihtokytkin. Jos vaihtoehtoinen virtalähde on heti saatavilla, niin vaihdon nopeus lähteestä toiseen on vain 500 ms. Tuoteperhe kattaa nyt virta-alueen 32 A – 630 A, verkkojännitteellä 220 V – 440 V. Tuotteita on saatavilla 2-, 3- ja 4-napaisina neljällä runkokoolla.

    https://www.se.com/fi/fi/product-range/64117628-transferpact/?parent-subcategory-id=4260&filter=business-4-s%C3%A4hk%C3%B6njakelu#overview

    Reply

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