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Topology of Continuous Availability for LED Lighting Systems

Topology of Continuous Availability for LED Lighting Systems

Giuseppe Parise – Marco Allegri

Sapienza – Università di Roma

Luigi Parise

Ospedale Pediatrico Bambino

Raffaele Pennacchia – Fabrizio Regoli

Italian Parliament

Giorgio Vasselli

3M Elettrotecnica Rome

Abstract: Lighting systems with a big number of luminaires in large halls are a case of distributed loads that need topologies with modularity, whenever possible to ensure a uniform distribution of the supplying circuits, an easier installation, management, and maintenance. The light emitting diode (LED) luminaires give a great impact on the system operation due to their auxiliary series devices and to the high inrush currents of the ac-dc switching power supplies. This article proposes a topology to design LED lighting systems, configured in a modular scheme of a main ac distribution and a branch dc distribution supplying luminaires clusters. Each cluster is provided as a “double-dual corded” equipment with double power supply and double control type, digital, and analogic. The suggested topology aims to make available a system that allows overcoming fault situations by design and permits maintenance activities limiting and recovering degradation conditions. In this way, the lighting system of special locations, for which there is the willingness-to-accept greater financial costs against loss service risks, can satisfy the requirement of continuous availability system. To provide more details on the proposed design criteria this article describes, as case study, the lighting system of a parliamentary hall with one thousands of luminaires.

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Heat Tracing

“Street in Røros in Winter” 1903 Harald Sohlberg

The National Electrical Contractors Association best practice catalog features a suite of titles (National Electrical Installation Standards to meet the intent of the National Electrical Code (NEC); particularly where the NEC asserts that an installation be constructed in a “neat and workmanlike manner”.   As anyone who has had to reckon with the subjectivity of the local electrical inspector knows, the determination of “neat and workmanlike” can be mighty subjective.   The NECA documents are used by construction owners, specifiers, contractors and electricians to clearly illustrate the performance and workmanship standards essential for different types of electrical construction.  Because the NEC is intended to be primarily a wiring safety standard, the NEIS suite is referenced throughout the National Electrical Code.  Electrical shop foremen and front line electricians take note.

NECA Standards and Publication Development Home Page

One of the NECA products that may be of interest to facility managers and risk management units in the education industry this time of year is NECA 202-2013 Standard for Installing and Maintaining Industrial Heat Tracing Systems.   About half of the United States deals with snow and ice half the year.

NECA 202 details procedures for the installation, testing, and documentation of electrical freeze protection and process heat tracing systems. Heat tracing cable types covered by this publication include: self-regulating, constant wattage, and zone heating cables and mineral insulated heating cables. 2 is approved as an American National Standard.   The 2013 edition is the current edition and will likely need revisiting/revision/reaffirmation as an American national standard soon.

The technical literature that keeps pipes breaking and roofs failing is complicated space. A common conundrum in the construction industry is which discipline (architectural, mechanical or electrical) should specify application of this technology; especially in value-engineering negotiations when each discipline is trying to reduce its unit costs. Control and communication system add another layer of complexity.  Several consensus standards occupy this technology; cross referencing one another and leaving gaps

ASCE 7-10 Snow Load Provisions

IEEE 515 Standard for the Testing, Design, Installation, and Maintenance of Electrical Resistance Trace Heating for Industrial Applications

UL 515 Standard for Electrical Resistance Trace Heating for Commercial Applications

IEC 62395 Electrical resistance trace heating systems for industrial and commercial applications

National Electrical Code Article 427

There are codes and standards developed by ASTM International, the International Code Council and ASHRAE International that set the standard of care for pipe insulation for energy conservation purposes but we will deal with the interdependence of standard of care set by those documents in a separate post.   Organizations such as FM Global typically derive their customer recommendations from consensus standards developers.

Because heat tracing is a cross-disciplinary technology we maintain it on the standing agenda of several colloquia: Power, Water, Bucolia, Snow & Ice and Mechanical   See our CALENDAR for the next meeting; open to everyone.  You may obtain an electronic copy of this standard from neis@necanet.org.  Communicate directly with Aga Golriz, (301) 215-4549, Aga.golriz@necanet.org.

Participation by the public in reviewing other titles in the NEIS bibliography is welcomed and begins at the page linked below:

Call for Public Review

Issue: [19-24]

Category: Architectural, Electrical, Facility Management, Mechanical, Risk Management,

Colleagues: Eric Albert, Mike Anthony, Jack Janveja, Richard Robben, Larry Spielvogel

 


More

RESEARCHGATE: HEAT-TRACING OF PIPING SYSTEMS TYPES OF HEAT-TRACING SYSTEMS

With some 36 million square feet under management — and one of the largest campuses in the United States exposed to extreme low temperatures — building industry professionals at the University of Michigan have some experience managing the competing requirements of safety and economy in heat tracing technology.

Potato Latkes

Traditional Hanukkah foods (Spoon University) are often fried or cooked in oil, symbolizing the miracle of the oil that lasted eight days in the rededication of the Second Temple in Jerusalem.

Latkes (Potato Pancakes): Grated potatoes mixed with onions, eggs, and flour, then fried until crispy. They are often served with applesauce or sour cream.

Sufganiyot (Jelly-filled Doughnuts): Deep-fried doughnuts filled with jelly or custard and dusted with powdered sugar. They represent the oil that miraculously burned for eight days.

Brisket: Slow-cooked beef brisket is a popular main course for Hanukkah dinners.

Applesauce: Often served as a topping for latkes or as a side dish.

Matzo Ball Soup: While traditionally associated with Passover, some families also serve matzo ball soup during Hanukkah. It consists of light, fluffy dumplings made from matzo meal in a chicken broth.

Kugel: A baked casserole dish that can be sweet or savory, made with noodles, potatoes, or other ingredients.

Chocolate Gelt: Chocolate coins wrapped in gold or silver foil, often used in the game of dreidel.

Dreidel Cookies: Cookies shaped like the spinning top used in the traditional Hanukkah game of dreidel.

Cheese: In reference to the story of Judith, who is said to have fed cheese to an enemy general to make him thirsty and then gave him wine to make him drunk.


Florida

“Stopping By Woods on a Snowy Evening”

Randall Thompson’s “Frostiana” is a choral cycle based on the poems of Robert Frost. The cycle consists of settings for mixed chorus and piano, and it was premiered in 1959. “Frostiana” was commissioned to celebrate the bicentennial of the town of Amherst, Massachusetts, and it features seven of Frost’s poems set to music by Thompson.

“Stopping by Woods on a Snowy Evening” is one of the poems included in the “Frostiana” cycle. The composition captures the reflective and contemplative mood of Frost’s poem, where the narrator pauses to admire the beauty of a snowy evening in a quiet forest. Randall Thompson’s musical setting adds another layer to Frost’s words, enhancing the emotional impact of the poem.

Thompson’s approach in “Frostiana” is characterized by its accessibility and tonal clarity. His settings aim to convey the meaning and atmosphere of Frost’s poetry through the expressive power of choral music. The entire “Frostiana” cycle is a celebration of both Thompson’s skill as a composer and Frost’s enduring contribution to American literature.

Acoustics

 

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