Hitachi LH1 Series

6-2
Chapter 6
Inspection and maintenance
6.2 Daily and periodic inspections
*1) The life span of the smoothing capacitor is influenced by the
ambient temperature. Refer to [Smoothing capacitor life span
curve] for replacing measures.
*2) The life span of the cooling-fan is influenced by the ambient
temperature, the dirt and the change in its environmental
conditions. Check these circumstances on the usual inspection.
*3) The estimated time before replacement (Number of years/cycle) and
the [Smoothing capacitor life span curve] are based on the design
lifespan, not guaranteed.
*4) In the case that the capacitors are replaced after that the storage
period of 3 years has expired, before the first use please refer to the
aging process under the following conditions before using them:
・First, apply for 1 hour the 80% of the capacitor rated voltage at
ambient temperature
・Then, raise the voltage to 90%, and keep it for 1 more hour.
・Finally, apply for 5 hours the rated voltage at ambient temperature
*5) In the case that the cooling-fan if affected by dust, obstructing it;
remove the dust, after that may take 5 to 10 seconds to start again.
*6) Follow the installed motor instructions.
Inspected
part
Inspection
entry
Details of inspection
Inspection cycle
Inspection method
Criterion
Tester device
Daily
Every
1
year
2
years
General
Surrounding
environment
Check the ambient temperature,
level of humidity, dust, … etc.
○
Refer to the installation guide.
Ambient temperature, level of
humidity are withing the range.
No frozen part. No condensation.
Thermometer
Hygrometer
Data logger
Whole inverter
Check abnormal vibrations or noises
○
Check visually and auditorily.
Without abnormalities
Power supply
voltage
Check that the main circuit voltage
is normal.
○
Measure the line-to-line
voltage of the inverter main
circuit terminals R,S and T.
Within the AC voltage
permissible variation.
Multimeter,
Digital multimeter
Meter
Main
circuit
General check
(1)Check the resistance between the
main circuit and the ground terminals.
○
Dismantle the inverter main
circuit terminals input/output
wiring and the control terminal
board, and remove the jumper
for the internal filter, after
that, shortcircuit the terminals
R,S,T,U,V,W,P,PD,N,RB,R0,T0,
and measure between this
shortcircuit and the ground.
Resistance no less than 5MΩ.
DC 500V class
Ohmmeter
(megger®)
(2)Check looseness in fastened parts
○
Confirm tighten of fasteners.
Without abnormalities
(3)Check for overheating traces.
○
Check visually.
Without abnormalities
Conductor and
cables
(1)Check for straining in conductors
○
Check visually.
Without abnormalities
(2)Check for cable coating damage
○
Terminal block
Check for any damage.
○
Check visually.
Without abnormalities
Inverter and
converter
circuits
(Including
resistors)
Check the resistance between all the
terminals
○
Remove the inverter main
circuit terminal wiring, and
measure the following:
- Resistance between
terminals RST and PN.
- Resistance between
terminals UVW and PN
Consult the “Method of
checking the inverter and
converter circuits”. The inverter,
capacitor and thyristor lifespan
before replacing the
componentes is of 10
6
start/stop cycles *3)
Analogue
multimeter
Smoothing
capacitor
(1)Check for capacitor fluid leakage
○
Check visually.
That there are no abnormalities
Estimated number life span
before exchanging component:
10 years
*1) *3) *4)
Capacitance
meter
(2)Check that the relief valve does not
swells or protudes.
○
Relay
(1)No chatter sound while operating
○
Check auditorily.
That there are no abnormalities.
(2)Check contacts for damage
○
Check visually.
That there are no abnormalities.
Control and
protection
circuits
Operation
check
(1) While performing a unit operation
of the inverter, check the balance of
the output voltage among the
individual phases
○
Measure the voltage between
the U,V,W terminals of the
inverter main circuit.
Phase-to-phase voltage balance
200V class: within 4V
400V class: within 8V
Digital multimeter
Voltmeter
Ammeter
(2)Carry out a sequential protection
test, and check the protective and
display circuits for any abnormality
○
Simulate a shortcircuit or open
of the inverter output
protection circuit.
An error must be detected
according to the sequence.
Cooling
system
Cooling-fan
(1) Check for abnormal vibrations or
noises
○
Turn by hand while electricity
is not being supplied
Smooth operation without
abnomalities.
Replace every: 10 years
*2) *3) *5)
(2)Check for loose joints
○
Check visually.
Heat sink
Check for obstructions/clogging.
○
Check visually.
That there are not obstructions.
Display
Display
(1)Check that LED lamps lights up
○
Check visually.
Confirm it lights up
(2)Display cleaning
○
With cleaning rag.
Meter
Check that Indicated values are
normal.
○
Check the meter readings on
the panel.
Regulation and control value
are satisfactory.
Voltmeter
Ammeter
Etc.
Motor
General
(1)Check abnormal vibrations or noises
○
Check visually,auditorily, and
by touch
Without abnormalities
(2)Check that there is no stench.
○
Check for abnormal
superheating, damages an so
on.
Without abnormalities
Insulation
resistance
Check the resistance between the
main circuit and the ground
terminals.
*6)
Detach the U,V,W terminals
from the inverter main circuit,
and shortcircuit the motor
wiring, mesure with the
Megger® between the motor
wiring and ground terminal.
No less than 5MΩ.
DC 500V class
Ohmmeter
(megger®)