GE Industrial Solutions ASTAT XT - Manual (Page 60)

60 • Trouble Shooting
Undercurrent FLT
Trips the ASTAT-XT when line current drops below the preset level for the preset time.
Check Undercurrent FLT and Undercurrent DLY settings; check line
currents of L1, L2, L3.
For protection parameters settings refer to section
4.7.2 page 27.
Undervoltage
Trips the ASTAT-XT when line voltage drops below the preset level for the preset time.
Check Undervoltage FLT and Undervoltage DLY settings, check line
voltages on L1, L2, L3. When voltage drops to zero, the ASTAT-XT trips immediately
with no delay.
For protection parameters settings refer to section
4.7.2 page 27.
Overvoltage
Trips the ASTAT-XT when line voltage increases above a preset level for a preset time.
Check Overvoltage FLT and Overvoltage DLY settings, check line voltage
on L1, L2, L3.
For protection parameters settings refer to section
4.7.2 page 27.
Phase Loss
Trips the ASTAT-XT if 1 or 2 phases are missing.
In cases where the current transformers are connected externally (ASTAT-XT 950-
1400A models), verify that that the current transformers are not grounded. Each
current transformer is connected with its 2 wires only and these wires are not
grounded externally.
Check phase voltages related to terminal 21 even if terminal 21 is not connected.
Verify that phase voltages are within the required range of line to neutral voltages.
Verify that terminal 21 is connected correctly. For terminal 21 connection refer to
section
8.1 page 62.
If terminal 21 is connected correctly, disconnect terminal 21 and try to start when
terminal 21 is disconnected.
If all previous actions are do not solve the problem and you are sure that no real
phase loss exists, you can set Phase Loss protection to Disable.
This situation can occur in rare cases when there is no real fault but the ASTAT-XT
recognizes unusual behaviour like when Total Harmonic Distortion in Voltage (THDV)
in the network is high.
If this is a true case of Phase Loss then after setting Phase Loss protection to Disable
the motor will single phase and most likely be tripped by the over load protection
mechanism.
Phase loss might not be detected in motor operating under a light load.
For Phase Loss protection setting refer to section
4.7.7 page 38.
Freq. or ph loss
Trips the ASTAT-XT if frequency is not in the range of 40-66.6Hz
Check that frequency variations are between 40-66.6Hz.
Phase Sequence
Trips the ASTAT-XT if line phase sequence is wrong.
Check line phase sequence and if wrong, swap two wires on line side. If motor now
rotates in the wrong direction, swap two wires on load side of the ASTAT-XT.
For Phase Sequence protection setting refer to section
4.7.7 page 38.
Slow Speed Time
Trips the ASTAT-XT when operating at slow speed for extended periods.
Check that operation time at Slow Speed is shorter than Max Slow Sp Time.
Note: Motor and ASTAT-XT may be overheated when operating at slow speed for an
extended period.
For Max Slow SP Time protection setting refer to section
4.7.6 page 37.