Acceleration Protection - GE 339 Instruction Manual

S3 PROTECTION

Acceleration protection

6–108
Figure 34: Fuse Fail Protection logic diagram
VOLTAGE INPUTS
V < 70%
ab
V < 70%
OR
bc
V < 70%
ca
VOLTAGE INPUTS
V > 85%
ab
V > 85%
OR
bc
V > 85%
ca
SETTI G
Fuse Fail Function
= Disabled
= Alarm
= Trip
MOTOR STATUS
Running
KEYPAD RESET
I PUTS
Emergency Restart Input
Lockout Reset Input
Reset Input
SETTI GS
S4 CO TROLS
Emergency Restart
Off = 0
Lockout Reset
Off = 0
Reset
Off = 0
The thermal model protects the motor under both starting and overload conditions. The
acceleration timer trip may be used to complement this protection. For example, if the
motor always starts in 2 seconds, but the safe stall time is 8 seconds, there is no point
letting the motor remain in a stall condition for the 7 or 8 seconds it would take for the
thermal model to operate. Furthermore, the starting torque applied to the driven
equipment for that period of time could cause severe damage.
If enabled, the Acceleration Protection will trip if the motor stays in the starting state and
does not reach the running state by the set acceleration time. Detection of starting and
running is as described in the motor status section of this manual. For two speed motor
applications, separate timer settings are provided for accelerating from stopped to low
speed, for accelerating from stopped to high speed, and for accelerating from low speed to
high speed.
If the acceleration time of the motor is variable, this feature should be set just beyond the
longest acceleration time.
PATH:
SETPOINTS > S3 PROTECTION > ACCELERATION
ACCEL TIME FUNC
Range: Disabled, Enabled
Default: Disabled
Enables Acceleration Protection tripping.
1 s
AND
0
AND
AND
AND
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 6: SETPOINTS
LOGIC OPERA D
Fuse Fail
LOGIC OPERA D
Fuse Fail Alarm OP
AND
Any Alarm OP
TARGET MESSAGE
Fuse Fail Alarm
State: Operate
Fuse Fail Trip
State: Operate
AND S
LOGIC OPERA D
Fuse Fail Trip OP
LATCH
Any Trip OP
R
Set Dominant
LOGIC OPERA D
Fuse Fail Inhibit
AND
Any Start Inhibit
OR
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