Hitachi SJ Series, User Manual

Page: 645 / 786

19-3
Chapter 19
Maintenance and Inspection
19.3 Daily Inspection and Periodic
Inspection
*1) The service life of smoothing capacitor is affected by the
ambient temperature.
See "5.Smoothing capacitor life curve"
to determine replacement period.
*2) The life of cooling fan varies depending on the environment
conditions such as ambient temperature and dust.
Check
operating conditions by daily inspection.
*3) The replacement period (number of years/cycles) and "5.
Smoothing capacitor life curve" are based on the designed
expected life, which is not a guaranteed value.
*4)
When you replace with a capacitor that has passed storage
period more than three years, perform aging in the following
conditions before using it.
・
Initially apply 80% of rated voltage of capacitor for one hour
in normal temperature
・
Then, increase the voltage to 90% and apply for one hour
・
Lastly, apply rated voltage for five hours in normal
temperature
*5) If the cooling fan is locked due to dust, etc., it takes about 5 to
10 seconds until re-rotation is enabled even if dust is removed.
*6) Perform inspection in accordance with the instruction manual
of motor.
Target
section
Item Details
Interval
Method Criteria
Measurement
instrument Daily
Periodic
1 year 2 years
General
Ambient
environment
Check the ambient temperature,
humidity, dust, etc.

See the installation method.
The ambient temperature and
humidity are within the usable
range. No freezing, condensation,
dust, corrosive gas, explosive gas,
flammable gas, mist of grinding
fluid, hydrogen sulfide, and salts
are permissible.
Thermometer
Hydrometer
Recorder
Entire device
No abnormal vibration or sound is
observed.

By visual check and hearing There must be no abnormality.
Power supply
voltage
The main circuit voltage is normal.

Measure line voltage between
inverter main circuit terminals R, S,
and T.
They are within the allowable
variation range of AC voltage.
Tester and
digital
multimeter
Main
circuit
General
(1) Megger check (between the main
circuit terminals and earth
terminals)

Remove the input/output wires of
main circuit terminal block of the
inverter, remove the control terminal
block board, then, remove the short
bar for switching the functions of
filter included in the inverter. Then,
using a megger, perform
measurement between each portion
where R, S, T, U, V, W, P, PD, N,
RB, R0, and T0 terminals are
shorted and earth terminal.
The measured value shall be
5MΩ or above.
DC
500V-class
megger
(2) Fastened portions are not
loosened.

Re-tighten the portion. There must be no abnormality.
(3) No residual mark of overheat is
observed on each component.

By visual check. There must be no abnormality.
Connected
conductor and
wire
(1) The conductor is not distorted.

By visual check. There must be no abnormality.
(3) The coatings of wires are not
torn.

Terminal block It is not damaged.

By visual check. There must be no abnormality.
Inverter
Converter
(including
resistor)
Check resistance between each
terminal

Remove the wires of the main circuit
terminal block of inverter, and
perform measurement between
terminals R, S, T and terminals P,
N, and between terminals U, V, W
and terminals P, N at the range of
tester ×1Ω.
See 6.5 Checking method of
inverter and converter.
Appropriate replacement interval
of inverter, converter, and
thyristor Start/stop: 10
6
cycles *3)
Analog tester
Smoothing
capacitor
(1) There is no leakage of fluid.

By visual check.
There must be no abnormality.
Appropriate service years for
replacement: 10 years *1) *3) *4)
(2) The belly (safety valve) shall not
stick and there shall be no bump.

Relay
(1) There shall be no beat noise
during operation.

By hearing. There must be no abnormality.
(2) There are no worn contacts.

By visual check. There must be no abnormality.
Control
circuit
Protective
circuit
Operation
check
(1) Through unit operation of
inverter, check balance of output
voltage between each phase.

Measure line voltage between
inverter main circuit terminals U, T,
and W. Inter-phase voltage balance
200V class: To be within 4V.
400V class: To be within 8V.
Digital
multimeter
Flowmeter
Voltmeter
(2) By conducting the sequence
protective operation test, check
there is no abnormality in
protective operation and display
circuit.

Simulate short or open condition of
the protective circuit output of
inverter.
The error is generated on the
sequence.
Cooling
system
Cooling fan
No abnormal vibration or sound is
observed.

By hearing and visual check.
(Warning indication on the operator
keypad) To rotate smoothly. There must
be no abnormality. Wind brows in
upper section.
Appropriate service years for
replacement: 10 years *2) *3) *5)
(2) Connections are not loosened.

By visual check.
Cooling fin There is no clogging.

By visual check. There is no clogging.
Indication
Indication
(1) The LED lamp and screen
display are normal.

By visual check. Check the lamp/display lights up.
(2) Cleaning.

Clean with a waste cloth.
External meter The indicated values are normal.

Check indicated values of the
meters on the boards. Satisfy the specification values
and control values. Voltmeter,
ammeter, etc.
Motor
General
(1) No abnormal vibration or sound
is observed.

By hearing, sensing, and visual
check.
There must be no abnormality.
(2) No abnormal smell is observed.

Check for abnormal smell due to
overheat, damage, etc.
There must be no abnormality.
Insulation
resistance
Megger check (between the main
circuit terminals and earth terminals)
*6)
Disconnect U, V, and W inverter
main circuit terminals, short the
motor line (for three phases), and
perform measurement between the
motor wire and earth terminal using
a megger.
The measured value shall be
5MΩ or above. DC 500V-class
megger