ELECTRICAL GROUNDING COURSES: GST OFFERS "ELECTRICAL GROUNDING AND "POWER QUALITY" COURSES, [IEEE and IEE Certified], SITE SURVEYS, LIGHTNING PROTECTION", ENGINEERING/DESIGN,LOW, MEDIUM & HIGH VOLTAGE POWER SYSTEMS. GG ELECTRICAL GROUNDING COURSES 1. Grounding for Electrical Distribution Systems. Basic Course (Two-day Course) 2. Electrical Grounding for Industrial Facilities. Advanced Course (Three-day Course) 3. Grounding and Bonding for the Telecommunications Industry. (Two-day Course) 4. Medium & High Voltage Substation Grounding. (Two-day Course) 5. Electrical Grounding for the Petrochemical Industry. (Two-day Course) POWER QUALITY COURSES 1. Power Quality Basic Course (Two-day Course) 2. Power quality Advanced Course (Two-day Course) FIRST COLUMN GOOGLE ADDS TRANSFORMERS BASICS BASIC TRANSFORMERS A basic transformer consists of two sets of coils or windings. Each set of windings is simply an inductor. AC voltage is applied to one of the windings, called the primary winding. The other winding, called the secondary winding, is positioned in close proximity to the primary winding, but is electrically isolated from it. The alternating current that flows through the primary winding establishes a time-varying magnetic flux, some of which links to the secondary winding and induces a voltage across it. The magnitude of this voltage is proportional to the ratio of the number of turns on the primary winding to the number of turns on the secondary winding. This is known as the “turns ratio.” To maximize flux linkage with the secondary circuit, an iron core is often used to provide a low-reluctance path for the magnetic flux. The polarity of the windings describes the direction in which the coils were wound onto the core. Polarity determines whether the flux produced by one winding is additive or subtractive with respect to the flux produced by another winding. Figure THREE PHASE TRANSFORMERS A basic 3-phase transformer consists of three sets of primary windings, one for each phase, and three sets of secondary windings wound on the same iron core. Separate single-phase transformers can be used and externally interconnected to yield the same results as a 3-phase unit. The primary windings are connected in one of several ways. The two most common configurations are the delta, in which the polarity end of one winding is connected to the non-polarity end of the next, and the wye, in which all three non-polarity (or polarity) ends are connected together. The secondary windings are connected similarly. This means that a 3-phase transformer can have its primary and secondary windings connected the same (delta-delta or wye-wye), or differently (delta-wye or wye-delta). It's important to remember that the secondary voltage waveforms are in phase with the primary waveforms when the primary and secondary windings are connected the same way. This condition is called “no phase shift.” But when the primary and secondary windings are connected differently, the secondary voltage waveforms will differ from the corresponding primary voltage waveforms by 30 electrical degrees. This is called a 308 phase shift. When two transformers are connected in parallel, their phase shifts must be identical; if not, a short circuit will occur when the transformers are energized. CONTACT US For more information Courses    Consulting  Instructors   Links   Courses in Canada    Wireless   Design & Engineering   Standards for Grounding   Translations English/Spanish   TO THE TOP Copyright 2005, Grounding Systems Technologies, Inc. ALL RIGHTS RESERVED.   CORPORATE ADDRESS 3309 e. Fairway Dr.,  Coeur D'Alene, Idaho 83815  USA Tels: (208) 964-0699    Contact us www.gstgrounding.com OUR REPRESENTATIVE IN THE CARIBBEAN ATESCO POWER LIMITED Ainsley Aarón 2 Crown Trace Lange Park, Chaguanas Trinidad W.I. Tel: 868 671-7143 Fax: 868 671-2191 Cell: 868 685-7283 Contact us OUR REPRESENTATIVE IN MEXICO NAJI CONSTRUCCIONES, S.A. ARQ. Fernando Nava Cefeo 5 Col. Prado Churubusco C.P. 04230 México, D.F. Tel./Fax: 5581-5118 Contacte nuestra Oficina