Service manual
Check control wiring to ensure that the proper reference
signal is present at the input terminals. Also check that the
unit is properly programmed to accept the signal provided.
Refer to the Input Terminal Signal Test.
Off 1 (2 or 3)
This message indicates that bit #1 (or #2, or #3) in the
control word is logic “0”. This situation only occurs when
the frequency converter is being controlled via the
fieldbus.
A correct control word must be transmitted to the
frequency converter over the communication bus.
STOP
One of the digital input terminals 16, 17, 27, 29, 32, or 33
is programmed for “Stop Inverse” and the corresponding
terminal is low (logic “0”).
Ensure that the above parameters are programmed
correctly and that any digital input programmed for “Stop
Inverse” is high (logic “1”).
Display Indication that the unit is functioning, but there is
no output.
Check that parameter 620 is not set to “Run With Inverter
Disabled”.
If the unit is equipped with external 24 V DC option, check
that the main power is applied to the frequency converter.
NOTE
In this case, the display alternately flashes Warning 8.
4.5.6 Incorrect Motor Operation
Occasionally, a fault can occur where the motor continues
to run, but not in the correct manner. The symptoms and
causes may vary considerably. Many of the possible
problems are listed below by symptom along with
recommended procedures for determining their causes.
Wrong speed/unit does not respond to command
Possible incorrect reference (speed command).
Ensure that the unit is programmed correctly according to
the reference signal being used, and that all reference
limits are set correctly as well. Perform 6.4.7 Input Terminal
Signal Tests to check for faulty reference signals.
Motor speed unstable
Possible incorrect parameter settings, faulty current
feedback circuit, loss of motor (output) phase.
Check settings of all motor parameters, including all motor
compensation settings (Slip Compensation, Load Compen-
sation, etc.). For Closed Loop operation, check PID settings.
Perform 6.4.7 Input Terminal Signal Tests to check for faulty
reference signals. Perform Output Phase Imbalance Test to
check for loss of motor phase.
Motor runs rough
Possible over magnetization (incorrect motor settings), or
an IGBT misfiring.
NOTE
Motor may also stall when loaded or the frequency
converter may trip occasionally on Alarm 13.
Check setting of all motor parameters, see 6.4.6 Output
Imbalance of Motor Supply Voltage Test.
If output voltage is unbalanced, see 6.4.6 Output Imbalance
of Motor Supply Voltage Test.
Motor draws high current but cannot start
Possible open winding in motor or open connection to
motor.
Perform 6.4.6 Output Imbalance of Motor Supply Voltage Test
to ensure that frequency converter is providing correct
output (see Motor Runs Rough above).
Check motor for open windings. Check all motor wiring
connections.
Run an AMA to check the motor for open windings and
unbalanced resistance. Inspect all motor wiring
connections.
4.6
Warnings and Alarms
When the frequency converter fault circuitry detects a fault
condition, or a pending fault, a warning, or alarm is issued.
A flashing display on the LCP indicates an alarm or
warning condition and the associated number code on line
2. Sometimes a warning precedes an alarm. defines
whether a warning precedes an alarm and whether the
frequency converter suspends operations (trips).
4.6.1
Alarms
An alarm causes the frequency converter to trip (suspend
operation). The frequency converter has three trip
conditions which are displayed on line 1:
TRIP (AUTO RESTART): The frequency converter is
programmed to restart automatically after the fault is
removed. The number of automatic reset attempts can be
continuous or limited to a programmed number of
attempts. If the selected number of automatic reset
attempts is exceeded, the trip condition changes to TRIP
(RESET).
TRIP (RESET): Requires resetting of the frequency converter
before operation after a fault is cleared. The frequency
converter can be reset manually by pressing [Reset], a
digital input, or a serial bus command. For FC 101
frequency converters, the stop and reset are the same key.
If [Stop/Reset] is used to reset the frequency converter,
[Start] must be pressed to initiate a run command in either
local or remote.
Troubleshooting
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®
HVAC Basic Drive Service Manual
34 MG90X202 - VLT
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