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CHAPTER 6: SETPOINTS
Contact inputs
NOTE:
NOTE
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
The 339 relay is equipped with ten (10) contact inputs, which can be used to provide a
variety of functions such as for circuit breaker control, external trips, blocking of protection
elements, etc. All contact inputs are wet type contacts (refer to the 339 typical wiring
diagram) that require an external DC voltage source. The voltage threshold (17V, 33V, 84V,
166V) is selectable, and it applies for all ten contact inputs.
The contact inputs are either open or closed with a programmable debounce time to
prevent false operation from induced voltage. Because of de-bouncing, momentary
contacts must have a minimum dwell time greater than half power frequency cycle. The
debounce time is adjustable by the user.
PATH:
SETPOINTS > S5 INPUTS/OUTPUTS > CONTACT INPUTS
SELECT DC VOLTAGE
Range: 17 V, 33 V, 84 V, 166 V
Default: 84 V
CONTACT INPUT 1
Range: 14 characters
Default: 52a Contact
CONTACT INPUT 2
Range: 14 characters
Default: 52b Contact
CONTACT INPUT X [3 to 10]
Range: 14 characters
Default: Input X
DEBOUNCE TIME
↘
CONTACT INPUT X [1 TO 10]
Range: 1 to 64 ms in steps of 1 ms
Default: 2 ms
Each of the contact inputs can be named to reflect the function it represents within the
application. Up to 14 alpha-numeric characters are available for names.
The debounce time is used to discriminate between oscillating inputs. The state will be
recognized if the input is maintained for a period consisting of the protection pass plus the
debounce setting.
Contact Input 1 and Contact Input 2 are named by the factory as 52a and 52b respectively
and are used for monitoring the breaker open/close state when wired to the breakers
auxiliary contacts 52a and 52b.
S5 INPUTS/OUTPUTS
6–145
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