GE M60 Instruction Manual

Also see for M60: Communications manual Communications guide Instruction manual Instruction manual

Contents

CHAPTER 5: SETTINGS GROUPED ELEMENTSM60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 5-1815This element receives current inputs from the source selected by the SETTINGS  SYSTEM SETUP  MOTOR  MOTORLINE SOURCE setting. Generally, this element compares the ratio of motor negative sequence current (I_2) to the positivesequence current (I_1) times an adjustment factor to compensate for the actual motor load to a set threshold. Theadjustment factor is used to prevent nuisance alarms at light loads. If the motor is operating at an average current levelequal to or greater than the programmed full load current (FLA, as selected by the SYSTEM SETUP  MOTOR  MOTORFULL LOAD AMPS setting) the adjustment factor is one. If the motor is operating at an average current level less than theprogrammed full load current (as selected by the SYSTEM SETUP  MOTOR  MOTOR FULL LOAD AMPS setting) theadjustment factor is the ratio of average current to full load current. It is intended that the Amp Unbalance 1 element isused to generate an alarm and Amp Unbalance 2 element is used to generate a trip.A declaration of a “single-phasing” condition is made two seconds after the unbalanced current level exceeds 40%, or theaverage current is above 25% of FLA and the current in any one phase is less than 2% of FLA.AMP UNBAL 1(2) PICKUP — This setting selects the level of unbalanced current that generates a stage 1 (intended to alarm)output. Note that a supply voltage unbalance of 1% creates a current unbalance of 6% in a typical three-phase inductionmotor; a supply voltage unbalance of 2% creates a current unbalance of 12%. As a 2% voltage unbalance is common inmost applications, a setting of 0.15 is often used as the alarm level, and AMP UNBAL 1 PICKUP is usually set to this level orhigher.AMP UNBAL 1(2) PICKUP DELAY — The alarm delay is often set from 5 to 10 seconds. A higher level of unbalance causesmotor stress in a shorter period; a reasonable setting is 3 to 10 seconds.AMP UNBAL 1(2) RESET DELAY — This timer can be used to maintain the output until other equipment or an operator canreact to the unbalance condition.Figure 5-93: AMP unbalance logic5.7.3.5 Mechanical jamSETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  MOTOR  MECHANICAL JAM AMP UNBAL 1 EVENTS:DisabledRange: Disabled, Enabled MECHANICAL JAM  MECHANICAL JAMFUNCTION: DisabledRange: Disabled, Enabled MECH JAM OVERCURRENTPICKUP: 2.00 x FLARange: 1.00 to 10.00 x FLA in steps of 0.01AMP UNBAL 1FUNCTION:AMP UNBAL 1BLK:AMP UNBAL 1PICKUP RESET:AMP UNBALANCE 1 PKPAMP UNBALANCE 1 DPOAMP UNBALANCE 1 OPAMP UNBAL 1PICKUP DELAY:AMP UNBAL 1PICKUP:SYSTEM SETUP/MOTOR/MOTOR LINE SOURCE:Off = 0RUNI_1IAIA < 0.02 FLA*IA+IB+IC3If Iavg FLA*, K=1If Iavg < FLA*, K=>=>=>== IavgIBIB < 0.02 FLA*ICIC < 0.02 FLA*UNBAL > 40 %Iavg 0.25 FLA*UNBAL PKP 1I_2Enabled = 1SETTINGSETTINGFLEXLOGIC OPERANDSFLEXLOGIC OPERANDSETTINGSETTINGSETTING833002A5.CDRNOTE:- FLA is programmed inSYSTEM SETUP / MOTOR / FULL LOAD AMPS*ANDANDANDANDORORORANDANDIavgFLA*Kx x100%I_2I_12s 0t PKPRSTtAMP UNBALANCEACTUAL VALUES