IEEE C37.2-2008 pdf download IEEE Standard for Electrical Power System Device Function Numbers, Acronyms, and Contact Designations
3.1.3 Device number 3-checking or interlocking relay
A device that operates in response to the position of one or more other devices or predetermined conditionsin a piece of equipment or circuit, to allow an operating sequence to proceed, or to stop, or to provide acheck of the position of these devices or conditions for any purpose.
3.1.4 Device number 4_master contactor
A device, generally controlled by device function I or the equivalent and the required permissive andprotective devices, that serves to make and break the necessary control circuits to place equipment intooperation under the desired conditions and to take it out of operation under abnormal conditions.
3.1.5 Device number 5stopping device
A control device used primarily to shut down equipment and hold it out of operation. [This device may bemanually or electrically actuated, but it excludes the function of electrical lockout (see device function 86)on abnormal conditions.
3.1.6 Device number 6starting circuit breaker
A device whose principal function is to connect a machine to its source of starting voltage.
3.1.7 Device number 7-rate-of-change relay
A device that operates when the rate-of-change of the measured quantity exceeds a threshold value, exceptas defined by device 63.
31.8 Device number 8-control power disconnecting device
A device, such as a knife switch, circuit breaker, or pull-out fuse block, used for the purpose of connectingand disconnecting the source of control power to and fromm the control bus or equipment.NOTE–Control power is considered to include auxiliary power that supplies such apparatus as small motors andheaters.
3.1.9 Device number 9-reversing device
A device that is used for the purpose of reversing the field of a machine or for performing any otherreversing function.
3.1.10 Device number 10-unit sequence switch
A device that is used to change the sequence in which units may be placed in and out of service in multipleunitequipmment.
3.1.11 Device number 11-multifunction device
A device that performs three or more comparatively important functions that could only be designated bycombining several device function numbers. All of the functions performed by device 11 shall be defined inthe drawing legend,device function definition list, or relay-setting record. See Annex A for furtherdiscussion and examples.
NOTE-If only two relatively important functions are performed by the device, it is preferred that both functionnumbers be used,as described in 3.7.