IEEE 303-1991 pdf free.IEEE Recommended Practice for Auxiliary Devices for Motors in Class I Groups A, B,C, and D, Division 2 Locations.
IEEE 303 practice is limited to auxiliary devices associated with motors operating in Division 2 areas,classified as Class I, Groups A, B,C, and D locations. This recommended practice is not an attempt to rewrite orotherwise supersede application sections of ANSINFPA 70-1990 [1],’ or any other codes or ordinances.Rather, it isintended to serve as a supplement to existing codes that in this area are not sufficiently specific to serve as a guide togood engineering practice. The guidance contained herein,therefore, is in addition to the ANSINFPA 70-1990requirements for wiring systems for hazardous (classified) locations.
The following information is intended to bring together a brief description of basic electrical practices in regard to theapplication and installation of auxiliary devices to motors operating in Class I, Groups A, B,C, and D, Division 2locations It should be understood that this information is only a guide to promote consistent application of suchdevices and must be used with sound engineering judgment.
auxiliary devices: Components installed either integrally within the motor, located adjacent to or mounted on themotor, or attached to its terminals for the purpose of monitoring the operating conditions or protecting the motor.Referto 5.2 and 5.3 for examples.
Class I,Division 2 Locations: Basically those in which there may be flammable gas present due to a failure of aprocess system. Under normal conditions a flammable mixture of gas is not present.
For a complete definition, refer to the latest edition of ANSINFPA 70-1990 [1],Chapter 5, Article 500.For a guide inestablishing the limits of these locations, refer to API-RP500-1991 [4] and ANSINFPA 497A-1986.
Included are bearing temperature switches or relays, certain types of motor winding temperature sensors,vibrationswitches, air filter differential pressure switches, zero speed switches, leak detector relays, and other types of relays orswitches either mounted inside a motor where there is a free exchange of ambient atmosphere or outside the motorhousing.IEEE 303 pdf download.