NEMA connector
NEMA connector are designated in accordance with the National Electrical Manufacturers Association number of different types of power plugs, mainly in America, particularly the U.S., and parts of Asia (Japan, partially Vietnam and China ) will apply. The contact number, and assignment is primarily designed for the usual in these countries, single-phase three-wire system. In Europe, NEMA plug with a few exceptions not applicable.
NEMA plugs are designed for voltages from 125 V to 600 V and maximum current rating of 15 A to 50 A. There are different types of plugs, which differ in the number, shape and arrangement of the contacts and in the mechanical form of the connector housings for the various applications. Their structure is specified in the ANSI / NEMA WD -6.
Types
The various types are distinguished by a number after the name. Individual plug of the standard is available in a version with an under mounted in the socket rotatable locking (English lock), which is marked with the letter L. The lock is designed to prevent accidental slipping out the plug from the socket by train on the plug. The individual plugs are further divided into different variants for high permissible current.
Referred addition to the simplest two-pin variant without ground connection NEMA -1, also known as Type -A, there are different variants for single-phase AC voltage as NEMA -5, also known as type -B. NEMA 5 are the most in use mains plug into the U.S., the operating voltage is 120 V at a line frequency of 60 Hz for large consumers such as electric ovens or dryers to plug the series NEMA 6 are provided. In the single-phase three-wire system is for those consumers twice the voltage of 240 V are available; Three-phase alternating current ( phase current) as in Europe is even available in North America for larger electricity customers, but especially in end-user terminals uncommon. Nevertheless, there are some special NEMA plug as NEMA L15, which are intended for use on three-phase alternating current.
The following are some of the common NEMA connector are shown.
NEMA 1
The connector NEMA 1, also referred to as type A, has two flat live contacts, which are arranged parallel to each other at a distance of 12.7 mm (1/2 inch). The connectors are used for very small consumers such as radios and operated in North America typically 120 V and 60 Hz. In Japan it is operated at 100 volts in China with 220 V.
NEMA 1 plug can be used in NEMA 5 - sockets.
NEMA 5
NEMA 5, also referred to as type B, has two flat live contacts, which are arranged parallel to each other. Size and spacing are identical to NEMA -1. A staggered additional round pin serves as a protective conductor contact. By this arrangement, the plug is polarized. The system is as NEMA -1 commonly used by small consumers with 110-127 V AC, 60 Hz mains frequency.
The protective conductor contact is longer than the two live contacts and is therefore connected when inserting before them, and separated only by them when unplugging.
In the NEMA 5 outlets are also childproof, which prevent an object is inserted into one of the two flat live contact openings. By a spring mechanism, the openings are only released when the two pins of the plug to be introduced at the same time. In Canada and parts of the United States, this child-safe outlets are required in new and renovated homes.
NEMA 6
NEMA 6 illustrate a series of " power plugs " that which are designed for 208-240 V up to 50 A and the ability to run larger loads such as heating and air conditioning equipment, clothes dryers and kitchen equipment or agricultural machines with increased power demand.