TAVRIDA ELECTRIC ISM Shell_2 Series, Applications Manual

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44
ISM Forced Trip by an Undervoltage Relay (Optional - CM_1501
Series)
In cases where the ISM is required to trip when the auxiliary power supply voltage drops below the minimum value
an additional undervoltage relay is required (not part of the scope of supply). The trip contact of the undervoltage
relay shall be integrated into the dry contact trip command circuit of the CM. If the CM was ready for operation
before the voltage dropped below the minimum value, tripping of the ISM is possible within 30 s after the voltage
dropped below the minimum level.
Note that for undervoltage trip functions it is recommended to use the CM_16 series where possible due to the
more flexible capability it provides for reclosing and UV trip delay.
Output to Magnetic Actuator and Input for ISM Pos ition
Indication
The cables between the ISM and CMnas well as the coils of the magnetic actuator are monitored permanently (see
malfunction indication table, page 43). Internally at the auxiliary switch inputs of the CM_1501 230 V DC is applied
for the ISM auxiliary switch S13. The CM_16 series does not utilize the auxiliary switch; instead the impedence of
the actuator coils is monitored for position of the breaker as well as loss of connection.
Operations Counter
Depending on site or switchgear requirements, a method of recording circuit breaker close / open operations may
be needed. The preferred method of tracking operations is to utilize the breaker wear monitor available on most
modern didgitical relays, which will calculate the remaining lifetime based on number of operations and switching
interruptions. Alternatively, a pulse counter per the table below can be ordered from Tavrida that will indicate the
number of mechanical operations. These counters can be wired to any of the 52a auxiliary contacts on the breaker.
Auxiliary Voltage Pulse Counter Part Number
24VDC 5RSI62.2 24C
48VDC 5RSI62.2 48C
120VAC 5RSI62.2 110
125VDC 5RSI62.2 110C
220VAC 5RSI62.2 220