Search results
Results from the WOW.Com Content Network
A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas, as symbolically it is similar to the letter 'Y'). A wye system allows the use of two different voltages from all three phases , such as a 230/400 V system which provides 230 V between the neutral (centre hub) and any one of the phases, and 400 V ...
The reverse star schema is a schema optimized for fast retrieval of large quantities of descriptive data. The design was derived from a warehouse star schema , [ 1 ] and its adaptation for descriptive data required that certain key characteristics of the classic star schema be "reversed".
The star schema is an important special case of the snowflake schema, and is more effective for handling simpler queries. [2] The star schema gets its name from the physical model's [3] resemblance to a star shape with a fact table at its center and the dimension tables surrounding it representing the star's points.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Microsoft Azure DevOps, Jira, Requirements.cc, Excel, Word Provides management of actors, use cases, user stories, declarative requirements, and test scenarios. Includes glossary, data dictionary, and issue tracking. Supports use case diagrams, auto-generated flow diagrams, screen mock-ups, and free-form diagrams. clang-uml: Unknown Unknown
The delta winding allows third-harmonic currents to circulate within the transformer, and prevents third-harmonic currents from flowing in the supply line. [2] Delta-wye transformers introduce a 30, 150, 210, or 330 degree phase shift. [3] Thus they cannot be paralleled with wye-wye (or delta-delta) transformers.
Set of three unbalanced phasors, and the necessary symmetrical components that sum up to the resulting plot at the bottom. In 1918 Charles Legeyt Fortescue presented a paper [4] which demonstrated that any set of N unbalanced phasors (that is, any such polyphase signal) could be expressed as the sum of N symmetrical sets of balanced phasors, for values of N that are prime.
Dahlander motor wiring for low speed (delta connection) and high speed (double star connection) The Dahlander motor is based on a 'consequent pole' connection. The primary factor in determining the speed of an induction motor is the number of poles, given by the formula = (RPM) where