IEEE Standard Electric Power System Device Function Numbers acc. to IEEE C.37.2-1991
Page 1 Issued: July 1998 Changed: since April 1996 Data subject to change without notice
Device function numbers standardized by IEEE and updated from time to time are used in many countries. Each number with its corresponding function name and the general description of eachfunction is listed below. For more information the relevant standards are to be consulted.
out of operation under abnormal conditions. 5. stopping device. A control device used primarily to shut down equipment and hold it out of operation. (This device may be manually or electrically actuated, but it excludes the function of electrical lockout [see device function 86] on abnormal conditions.) 6.starting circuit breaker. A device whose principal function is to connect a machine to its source of starting voltage. 7. rate-of-rise relay. A relay that functions on an excessive rate-of-rise of current. 8. control power disconnecting device. A disconnecting device, such as a knife switch, circuit breaker, or pull-out fuse block, used for the purpose of respectively connecting and disconnectingthe source of control power to and from the control bus or equipment. NOTE: Control power is considered to include auxiliary power that supplies such apparatus as small motors and heaters. 9. reversing device. A device that is used for the purpose of reversing a machine field or for performing any other reversing functions. 10. unit sequence switch. A switch that is used to change the sequence inwhich units may be placed in and out of service in multiple-unit equipment. 11. multifunction device. A device that performs three or more comparatively important functions that could only be designated by combining several of these device function numbers. All of the functions performed by device 11 shall be defined in the drawing legend or device function definition list.
Standard deviceFunction numbers:
1. master element. The initiating device, such as a control switch, etc., that serves, either directly or through such permissive devices as protective and time-delay relays, to place equipment in or out of operation. NOTE: This number in normally used for a hand-operated device, although it may also be used for an electrical or mechanical device for which no other function number issuitable. 2. time-delay starting or closing relay. A device that functions to give a desired amount of time delay before or after any point of operation in a switching sequence or protective relay system, except as specifically provided by device functions 48, 62, and 79. 3. checking or interlocking relay. A relay that operates in response to the position of a number of other devices (or to anumber of predetermined conditions) in equipment to allow an operating sequence to proceed, stop, or provide a check of the position of these devices or conditions for any purpose. 4. master contactor. A device, generally controlled by device function 1 or the equivalent and the required permissive and protective devices, that serves to make and break the necessary control circuits to place equipmentinto operation under the desired conditions and to take it
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ANSI numbers IEEE Standard Electric Power System Device Function Numbers acc. to IEEE C.37.2-1991
NOTE: If only two relatively important functions are performed by the device, it is preferred that both function numbers be used, as described in 3.6. 12. overspeed device.Usually, a direct-connected speed switch that functions on machine overspeed. 13. synchronous-speed device. A device such as a centrifugal-speed switch, a slipfrequency relay, a voltage relay, an undercurrent relay, or any other type of device that operates at approximately the synchronous speed of a machine. 14. underspeed device. A device that functions when the speed of a machine falls below a...