01/01/2008 - Volume IV - Issue I
Siprotec 7SJ62 - an ideal retrofit for SAMMS motor management relay
The SAMMS (Siemens Advanced Motor Master System) unit is a microprocessor based device designed to provide complete control and protection for low-voltage or medium-voltage motors. The SAMMS unit is also a dedicated logic controller programmable for all common starter configurations.
With a large number of customers still using the out-of-production SAMMS, Siemens offers the SIPROTEC 7SJ62 as a direct replacement solution. The SIPROTEC 7SJ62 offers protection and control for a wide range of motor applications, ranging from low-voltage to medium-voltage and small to very high horsepower rating.
The SIPROTEC 7SJ62 is a microprocessor device which can provide all the protection and control needs to retrofit SAMMS units. The same 7SJ62 is capable of retrofitting both SAMMS-MVE and SAMMS-MVX. The continuous function chart capability[CFC] of the SIPROTEC family offers the logic programming using the universally accepted logical Boolean gates, i.e. AND, OR etc.
Protection settings offered by 7SJ62 surpass the available protections for either SAMMS-MVE or SAMMS-MVX.
Up to four pushbuttons can be realized via the function keys of the 7SJ62, while the motor start and stop commands are realized using front panel commands.
The major advantages of 7SJ62 are:
Industry standard communication protocol
Ease of parameterization with user friendly GUI, DIGSI
Up to four different setting groups.
Seven programmable LEDs, Self-test LED, Run LED, front communication RS-232 port, and bright four line LCD display are amongst the many features makes the Siemens 7SJ62 an ideal retrofit solution for SAMMS-MV units.
SIPROTEC 7SJ62 functional overview
Neutral fault protection
Ground fault protection
Undercurrent monitoring, loss of load
Starting time supervision
Phase sequence monitoring
Breaker failure protection
Cold load pickup
Under voltage protection
Over voltage protection
Ladder logic can be realized using CFC
Commands and control of breakers and contactors
Control via keypad, digital inputs, DIGSI 4, or SCADA system.
Operational measured currents (la, lb, lc, ln, or lGnd)
Operational measured voltages (Vab, Vbc and Vca or Van, Vbn, and Vcn)
Power measurement (P,Q,S)
Energy metering values (Wp+, Wp-,Wq+, Wq-)
Circuit-breaker wear monitoring
Trip circuit supervision
Communication connection supervision.
System interface---MODBUS RTU---DNP 3.0---PROFIBUS DP / IEC 60870
Service interface for DIGSI 4
Front interface for DIGSI 4
Time Synchronization via IRIG B / DCF77.