Mitsubishi FREQROL-SF, Troubleshooting Manual

Page: 35 / 219

Alarm Inverter Overcurrent
Item Cause
Check Remedy
The input power voltage
Observe the voltage waveforms Increase the power capacity.
waveform is defective. at the input terminals Xl, X2,
and X3 of the amplifier using
Thicken the size of the
an oscilloscope.
cable between the input
power supply and amplifier.
Check that the voltage wave-
forms are as follows even in
Check other semiconductor
the acceleration or
devices which generate
tion state.
distorted waveforms and
install surge killers and
If the waveform is
tially lost:
so force.
(For example, MATSUO made,
rating 200 VAC,
12003-5041, etc.)
1
It should be
100 us or less.
If the peak value drops:
It should be
2 to 3% or
less.
The input power
Check that the alarm occurs Replace the power supply
is high. only when the motor speed
with an other one whose
(Example,
in the cases decelerates from a high power impedance is low.
that two transformers speed.
2
are connected in series
Tighten the screws of
or a variable
Check that the input voltage
between the input
transformer is con-
temporarily drops to 170 V power supply and amplifier.
or less when the motor
decelerates.
The input power
Check the voltage frequencies Check the cause of the fre-
quency remarkably at the input terminals Xl, variation and
3
changes.
and X3 of the amplifier the related controls so
using a frequency counter.
that it is in the specifica-
tion range.
The motor selection
4
parameters and
Check that the parameters are Correctly set the
correctly set by referencing meters.
are not correctly set. Reference 1.2.2. (See Reference
The transistor module
Check that this alarm occurs Replace the main circuit
is defective. even after the equipment is unit of the amplifier with
reset. a new one.
Disconnect the cable between
5 the amplifier and motor and
check that this alarm occurs
when only the amplifier is
operated.
(See Appendix l-2.1
Continued on the next page.