High Speed Thermal Protection; High Speed Short Circuit Settings - GE 339 Instruction Manual

S3 PROTECTION
High speed thermal
protection
High speed short
circuit settings
6–118
HIGH SPEED SWITCH
Range: Off, Contact Input 1 to 10, Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 16
Default: Off
If the two-speed motor functionality is used, this setting specifies a contact input to
indicate the motor high speed.
LOW SPEED SWITCH
Range: Off, Contact Input 1 to 10, Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 8
Default: Off
If the two-speed motor functionality is used, this setting specifies a contact input to
indicate the motor low speed.
When the two-speed functionality is enabled, the 339 will switch settings between
PROTECTION > THERMAL PROTECTION
to ensure proper parameters are applied to each speed. The motor
SPEED THERMAL
thermal characteristics for high and low speed can be different, so separate FLA and curve
selections are provided for high speed operation. In applications where the motor has the
same thermal characteristics for both low and high speed, set the high speed Thermal O/L
Curve to be the same as the main settings.
For a single speed motor where the two-speed functionality is disabled, the 339 will apply
S3 PROTECTION > THERMAL PROTECTION
PATH:
SETPOINTS > S3 PROTECTION > TWO SPEED MOTOR > HIGH SPEED THERMAL
CURVE MULTIPLIER
Range: 1 to 15 in steps of 1
Default: 4
This setting is used to fit a standard overload curve to the thermal characteristics of the
protected motor when it is running at High Speed.
When two-speed functionality is enabled, a second independent Short Circuit element is
provided for High Speed. When the motor is running at high speed and any phase current
exceeds the high speed short circuit pickup level for the high speed short circuit time delay,
the high speed short circuit protection will be activated. In cases where the switching
device is a contactor, which is not designed to cut off fault current, the function of short
circuit can be set as either Latched Alarm or Alarm, so the assigned auxiliary output relay
will be activated and signal an upstream breaker to trip.
PATH: SETPOINTS > S3 PROTECTION > TWO SPEED MOTOR > HIGH SPEED S/C
S/C FUNC
Range: Disabled, Latched Alarm, Alarm, Trip
Default: Disabled
The selection of the Latched Alarm, Alarm or Trip setting enables the High Speed Short
Circuit function. If the operating condition is satisfied when Trip is selected as the
function, the "LOCKOUT" LED will be turned on, and the logic operand ANY TRIP OP will be
asserted, which in turn will operate the "TRIP" LED and the trip output relay. If Alarm is
selected, the "ALARM" LED will flash upon the short circuit protection operation, and will
automatically reset when the activating condition clears. If Latched Alarm is selected,
the "ALARM" LED will flash upon short circuit protection operation, and will stay "ON"
after the condition clears, until a Reset command is initiated. The TRIP output relay will
not operate if the Latched Alarm or Alarm function is selected. Any assignable output
relays can be selected to operate when the setting S/C FUNC is selected as Latched
Alarm, Alarm, or Trip.
and
S3 PROTECTION > TWO SPEED MOTOR > HIGH
settings to protect the motor.
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 6: SETPOINTS
S3