8-20
H If the Motor Rotates Even When Inverter Output is Stopped
The
DC braking is not operating properly
. If
the motor continues operating at low speed, without com
-
pletely stopping, and after a deceleration stop has been executed, it means that the DC braking is not
decelerating enough. Adjust the DC braking as follows:
S Increase the parameter b2-02 (DC injection braking current) setting.
S Increase the parameter b2-04 (DC injection braking time at stop) setting.
H If 0 V is Detected When the Fan is Started, or Fan Stalls
DC
braking is insuf
ficient at startup. Generation of 0 V and stalling can occur if the fan is turning when
it
is started. This can be prevented by slowing fan rotation by DC braking before starting the fan. In-
crease the parameter b2-03 (DC injection braking time at start) setting.
H If Output Frequency Does Not Rise to Frequency Reference
• The frequency reference is within the jump frequency range.
When
the
jump frequency function is used, the output frequency does not change within the jump fre
-
quency
range. Check to be sure that the jump frequency (parameters d3-01 to d3-03) and jump fre
-
quency width (parameter d3-04) settings are suitable.
• The frequency reference upper limit has been reached.
The output frequency upper limit is determined by the following formula:
Maximum output frequency (E1-04) x Frequency reference upper limit (d2-01) / 100
Check to be sure that the parameter E1-04 and d2-01 settings are suitable.
H Inverter Overload “OL2” is Detected
For
a 400-V Inverter
, if the carrier frequency “C6-01” is set to a value higher than the default setting, the
Inverter
overload “OL2” detection value will decrease in consideration of an increase in the heat that will
be generated by the change in the carrier frequency. Since the detection value is set to decrease by
approximately
15% for every increase of 2 kHz from the default setting , the Inverter overload “OL2” may
be
detected prior to the motor overload “OL1” depending on the set value. Set the carrier frequency to a
lower level.
H If Inverter Does Not Operate Due to an EF Error (Forward and Reverse
Commands Input)
D The sequence is faulty.
The
EF error will be detected if the forward command and reverse command are input at
the same time
for over 0.5 seconds. Check and correct the sequence.
D Stray current causes malfunction.
The
Inverter input may always remain ON due to stray current from the control section. As shown in the
following illustration, a current may flow in the direction shown by
an
arrow to turn ON the Inverter input
Maintenance Operations Chapter
8
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