GE 339

CHAPTER 6: SETPOINTS S3 PROTECTION
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 6–103
If the two-speed motor feature is enabled, the setting HIGH SPEED SWITCH specifies a
contact input to monitor the high speed contact position, and the setting LOW SPEED
SWITCH specifies another contact input to monitor the low speed contact position. It is
recommended to monitor both high and low speed switches, but using only one of them is
also acceptable. When the motor speed is indicated as HIGH SPEED, the relay uses the
high speed settings. When the motor speed is indicated as LOW SPEED, the relay uses the
same settings as those used for single speed operation. The logic for motor speed
indication is shown in the table below.
The two-speed motor feature is enabled with the setting S2 SYSTEM SETUP > MOTOR >
ENABLE 2-SPD MOTOR. When the two-speed feature is enabled, the 339 provides the
second independent Short Circuit and Undercurrent elements for High Speed, and adjusts
the thermal overload curve and acceleration timer as per the high speed motor
characteristics.
Two-speed motor
setup
PATH: SETPOINTS > S2 SYSTEM SETUP > MOTOR
ENABLE 2-SPD MOTOR
Range: Disabled, Enabled
Default: Disabled
This setting is used to enable two-speed motor functionality. When this setting is
selected as Disabled, all two-speed motor functionalities will be disabled, and all other
two-speed motor-related settings are hidden.
HIGH-SPEED PH PRIM
Range: 10.0 to 5000.0 A in steps of 0.1 A
Default: 100 A
This setting is used to specify the Phase CT primary for High Speed.
HIGH-SPEED FLA
Range: 5.0 to 5000.0 A in steps of 0.1 A
Default: 100.0 A
This setting is used to specify the Full Load Amps for High Speed.
HIGH-SPEED RATED PWR
Range: 100 to 10000 KW in steps of 1 KW
Default: 3000 KW
This setting is used to specify the rated power for High Speed.
Setting Speed Switch Inputs Motor
Speed
Indication
ENABLE 2-SPD
MOTOR
High Speed
Switch
Low Speed
Switch
High Speed
S2
Low Speed
S1
Enable Configured Configured Closed Open High Speed
Open Closed Low Speed
Open Open Alarm: SPD
SW Fail
Closed Closed
Configured Not Configured Closed N/A High Speed
Open N/A Low Speed
Not Configured Configured N/A Closed Low Speed
N/A Open High Speed
Not Configured Not Configured N/A N/A Alarm: SPD
SW Not
Config
Disable Two-speed functionality is not enabled.