Motor - GE 869 Instruction Manual

CHAPTER 5: STATUS

Motor

869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
The motor start screen is shown as follows.
Path:
Status > Motor
MOTOR STATUS: STOPPED
Range: Tripped, Stopped, Starting, Running, Overload
Default: Stopped
These messages describe the motor status at any given point in time. All motor status
operands are mutually exclusive.
Motor Stopped and Tripped conditions are detected based on the current level and
switching device status (52a or 52b). For the case when switching device(breaker or
contactor) is not configured (i.e., setpoints Contact Input 52a or Contact Input 52b are set
to "Off" under
Setpoints > Control > Breaker > Contactor
connected (i.e. FlexLogic operands "BRK1 Connected" or "Contactor Connected" are not
asserted (under Setpoints > Control > Breaker or Contactor) then monitoring of switching
device status is no more possible, the Stopped, Tripped and Start will then be based on
the monitoring of current level only.
The Motor Tripped condition is detected when Any Trip operand is asserted and the
current is below 2% of CT and the switching device is open. However, when the switching
device is not configured then the Motor Tripped condition is detected when Any Trip
operand is asserted and the current is below 2% of CT. Resetting of the Motor Tripped
can be done by resetting the trip condition.
The state machine initially sets the Motor Stopped operand, as the switching device is
open and motor current is less than 2% of CT. Also, to detect a Motor Stopped condition
it is important to first reset any trip or the Any Trip operand is deserted. When the
switching device is not configured the Motor Stopped condition is detected based on
current only. Also, for the case when motor condition or status is solely based on the
monitoring of currents, idling condition (current becomes ideally zero) during Motor
Running in synchronous motor application can result in the Motor Stopped instead of
Motor Running. To prevent this, the 869 must always be programmed to monitor the
status of the switching device by means of contact input of the relay.
Motor Starting is asserted if the previous motor status is Motor Stopped and a load
current greater than 2% of FLA is detected, the Motor Starting operand becomes true.
The Motor cannot start if the previous condition is Motor Tripped unless Any Trip is reset.
For normal motor starting, the Motor Starting condition remains asserted until currents
fall below FLA x Overload Factor setting. As soon as motor current falls below FLA x the
Overload Factor setting, the Motor Running operand is set. Also, the motor can only be in
the running condition when Motor Starting and Motor Overload are deserted and the
previous condition is either Motor Starting or Motor Overload.
If current rises above FLA x Overload Factor at that point, the Motor Overload operand is
set. If current then falls below FLA x Overload Factor, the Motor Overload operand is
reset and the Running operand is set in 2 Speed Motor applications, when the motor is
switched from speed 1 to speed 2, FLA and CT Primary will switch to "Speed2 Motor FLA"
and Speed2 CT Primary (both set under System > Motor > Setup). In addition, during the
transition from speed 1 to speed 2 it may be possible that the current drops below 2%
and the Motor Stopped status becomes true. To prevent this, if the previous status is
Running (or Starting or Overload) and the 2-Speed Motor Protection is "Enabled" and the
Speed2 Motor Switch is true, then the motor status (Motor Running, Starting or Overload)
MOTOR
) or breaker or contactor are not
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