Block ads by default when you upgrade.
ANSI Device Numbers
1. Master Element
Initiating device, such as a control switch, that operates either directly or through other permissive devices to place equipment in or out of service.
2. Time Delay Starting or Closing Relay
Functions to give a desired amount of time delay before or after any point of operation in a switching sequence or protective relay system.
3. Checking or Interlocking Relay
Operates in response to the position of other devices in an equipment, to allow an operating sequence to proceed, or to stop.
4. Master Contactor
Serves to make and break the necessary control circuits to place an equipment into operation under the desired conditions and to take it out of operation under other or abnormal conditions.
5. Stopping Device
Used to shut down equipment and hold it out of service, excluding the function of electrical lockout (device 86) on abnormal conditions.
6. Starting Circuit Breaker
Connects a machine to its source of starting voltage.
7. Rate of Change Relay
A device that operates when the rate-of-change of the measured quantity exceeds a threshold value, except as defined by device 63.
8. Control Power Disconnecting Device
Knife switch, circuit breaker, or pull-out fuse block, used for the purpose of connecting and disconnecting the source of control voltage to and from a control bus or piece of equipment, including auxiliary power feeding small motors and heaters.
9. Reversing Device
Used for the purpose of reversing a machine field or for performing any other reversing functions.
10. Unit Sequence Switch
Device used to change the sequence in which units may be placed in and out of service in multiple-unit configurations.