GE 469 Instruction Manual

Also see for Masoneilan 469 Series: Instruction manual Instruction manual Instruction manual Communications guide Instruction manual

Contents

S7 Motor Starting 469Motor Management RelaySetpointshttp://www.GEindustrial.com/multilin 5–55GE MultilinS7 Motor StartingAcceleration Timer PATH: SETPOINTS ZV S7 MOTOR STARTING Z ACCELERATION TIMERThe thermal model protects the motor under both starting and overload conditions.The acceleration timer trip may be used to complement this protection. Forexample, if the motor always starts in 2 seconds, but the safe stall time is 8seconds, there is no point letting the motor remain in a stall condition for 7 or 8seconds when the thermal model would take it off line. Furthermore, the startingtorque applied to the driven equipment for that period of time could cause severedamage.If enabled, the Acceleration Timer functions as follows. A motor start is assumed tobe occurring when the 469 measures the transition of no motor current to somevalue of motor current. Typically current rises quickly to a value in excess of FLA(e.g. 6 x FLA). At this point, the acceleration timer will be initialized with theACCELERATION TIMER FROM START value in seconds. If the current does not fall belowthe overload curve pickup level before the timer expires, an acceleration trip willoccur. If the acceleration time of the motor is variable, this feature should be setjust beyond the longest acceleration time.Some motor soft-starters allow current to ramp up slowly while others limit currentto less than FLA throughout the start. Since the 469 is a generic motor relay, itcannot differentiate between a motor with a slow ramp up time and one that hascompleted a start and gone into overload. Therefore, if the motor current does notrise to greater than full load within 1 second on start, the acceleration timer featureis ignored. In any case, the motor is still protected by the overload curve.Start Inhibit PATH: SETPOINTS ZV S7 MOTOR STARTING ZV START INHIBITThe Start Inhibit feature prevents motor tripping during start if there is insufficientthermal capacity. The largest THERMAL CAPACITY USED value from the last fivesuccessful starts is multiplied by (1 + TC USED MARGIN) and stored as the LEARNEDSTARTING CAPACITY. This thermal capacity margin ensures a successful motor start. Ifthe number is greater than 100%, 100% is stored as LEARNED STARTING CAPACITY. Asuccessful motor start is one in which phase current rises from 0 to greater thanoverload pickup and then, after acceleration, falls below the overload curve pickuplevel. If the Start Inhibit feature is enabled, the amount of thermal capacityavailable (100% – THERMAL CAPACITY USED) is compared to the LEARNED STARTINGCAPACITY each time the motor is stopped. If the thermal capacity available does notexceed the LEARNED STARTING CAPACITY, or is not equal to 100%, the Start InhibitBlock is activated until there is sufficient thermal capacity. When a block occurs, thelockout time will be equal to the time required for the motor to cool to an acceptablestart temperature. This time is a function of the S5 THERMAL MODEL Ö THERMAL MODELÖØ COOL TIME CONSTANT STOPPED setpoint. ACCELERATION [Z]TIMERACCELERATION TIMERTRIP: OffRange: Off, Latched, UnlatchedMESSAGE ASSIGN TRIP RELAYS:TripRange: Trip, Trip & Auxiliary2, Trip &Aux2 & Aux3, Trip & Auxiliary3MESSAGE ACCELERATION TIMERFROM START: 10.0 sRange: 1.0 to 250.0 s in steps of 0.1 START [Z]INHIBITSTART INHIBITBLOCK: OffRange: On, OffMESSAGE TC USEDMARGIN: 25%Range: 0 to 25% in steps of 1