5-194 M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUALGROUPED ELEMENTS CHAPTER 5: SETTINGS5The thermal model is the primary protective function of the relay. It consists of the following five key functions:• Thermal model curve (overload)• Overload pickup level• Unbalance biasing of the motor current while the motor is running• Motor cooling time constants• Biasing of the thermal model based on hot/cold information and/or measured stator temperatureThe algorithm integrates both stator and rotor heating into a single model. The motor heating level is maintained in thethermal capacity used register. When the motor has been stopped for a long time, it is at ambient temperature andthermal capacity used is zero. When the motor is in overload, the output operand is set once the thermal capacity usedreaches 100%. HOT/COLD SAFESTALL RATIO: 1.00Range: 0.01 to 1.00 in steps of 0.01 RTD BIAS:DisabledRange: Disabled, Enabled RTD BIAS MINIMUM40 CRange: 0 to 250°C in steps of 1 RTD BIAS CENTERPOINT: 130 CRange: 0 to 250°C in steps of 1 RTD BIAS MAXIMUM:155 CRange: 0 to 250°C in steps of 1 START INHIBITTCU MARGIN: 0%Range: 0 to 25% in steps of 1 VOLTAGE DEPENDENTFUNCTION: DisabledRange: Disabled, Enabled VOLTAGE DEPENDENTMIN MOTOR VOLTS: 80%Range: 60 to 99% in steps of 1 VD VOLTAGE LOSS:OffRange: FlexLogic operand VD STALL CURRENT @MIN V: 4.50 x FLARange: 1.50 to 20.00 x FLA in steps of 0.01 VD SAFE STALL TIME @MIN V: 20.0 sec.Range: 0.1 to 1000.0 s in steps of 0.1 VD ACCELL. INTERSECT@ MIN V: 4.00 x FLARange: 1.50 to 20.00 x FLA in steps of 0.01 VD STALL CURRENT @100% V: 6.00 x FLARange: 1.50 to 20.00 x FLA in steps of 0.01 VD SAFE STALL TIME @100% V: 10.0 sec.Range: 0.1 to 1000.0 s in steps of 0.1 VD ACCELL. INTERSECT@100% V: 5.00 x FLARange: 1.50 to 20.00 x FLA in steps of 0.01 THERMAL MODELBLOCK: OffRange: FlexLogic operand THERMAL MODELTARGETS: Self-ResetRange: Self-reset, Latched, Disabled THERMAL MODELEVENTS: DisabledRange: Disabled, Enabled
