96 • Trouble Shooting
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UNDER VOLTAGE
Trips the RVS-DN when line voltage drops below the preset level for
the preset time.
Check UNDERVOLT. TRIP and UNDERVOLT. DELAY settings, check line
voltages on L1, L2, L3. When voltage drops to zero, the RVS-DN trips immediately
with no delay.
For protection parameters settings refer to section
7.7.2 page 69.
OVER VOLTAGE
Trips the RVS-DN when line voltage increases above a preset level for
a preset time.
Check OVERVOLT. TRIP and OVERVOLT. DELAY settings, check line voltage on
L1, L2, L3.
For protection parameters settings refer to section
7.7.2 page 69.
PHASE LOSS
Trips the RVS-DN if 1 or 2 phases are missing.
(1) In cases where the current transformers are connected externally (RVS-DN
950-3000A 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.
(2) 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.
(3) Verify that terminal 21 is connected correctly. For terminal 21 connection refer
to section
4.1 page 19.
(4) If terminal 21 is connected correctly, disconnect terminal 21 and try to start
when terminal 21 is disconnected.
(5) If all previous actions are do not solve the problem and the you are sure that
no real phase loss exists, you can set PHASE LOSS Y/N protection to NO.
This situation can occur in rare cases when there is no real fault but the RVS-
DN recognizes unusual behaviour like when Total Harmonic Distortion in
Voltage (THDV) in the network is high.
(6) If this is a true case of PHASE LOSS then after setting PHASE LOSS Y/N
protection to NO the motor will single phase and most likely be tripped by the
over load protection mechanism.
(7) Phase loss might not be detected in motor operating under a light load.
For PHASE LOSS protection setting refer to section
7.7.7 page 81.
PHASE LOSS setting is not valid in RVS-DN 1000V and RVS-DN 1200V.
FREQUENCY
Trips the RVS-DN if frequency is not in the range of 40-66.6Hz
Check that frequency variations are between 40-66.6Hz.
PHASE
SEQUENCE
Trips the RVS-DN 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 RVS-DN.
For PHASE SEQUANCE protection setting refer to section
7.7.7 page 81.
MAX SLOW SP
TIME
Trips the RVS-DN 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 RVS-DN may be overheated when operating at slow speed for an
extended period.
For MAX SLOW SP TIME protection setting refer to section
7.7.6 page 80.
WRONG
CONNECTION
Trips the RVS-DN when one or more motor phases is not properly
connected to RVS-DN’s load terminals or if there is an internal
disconnection in the motor winding.
Verify that the motor is connected properly.
See note 1 at the end of this section.
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