Hitachi SJ700-2 instruction manual Daily and Periodic Inspections, Ground terminals with a megger

Chapter 6 Maintenance and Inspection

6.2 Daily and Periodic Inspections

Part to

Inspection cycle

inspect

Inspection item

Detail of inspection

Daily

Periodic

Inspection method

Criterion

Test equipment

Annual

Biennial

General

Environment

Check the ambient temperature,

See Section 2.1, "Installation."

The ambient temperature must

Thermometer,

humidity, and dust.

be within -10°C to +50°C without

hygrometer,

{

congelation.

The

ambient

recorder

humidity must be 90% RH or less

without condensation.

Whole inverter

Check for abnormal vibrations and

{

Check visually and by listening.

There must be no abnormality

noise.

found.

Power supply

Check that the main circuit voltage

Measure the voltage between the

The measured voltage must be

Tester, digital

voltage

is normal.

{

main circuit terminals R, S, and T.

within the allowable tolerance for

multimeter

AC power voltage.

Main

General check

(1) Check the ground resistance

Disconnect all input and output cables

500 VDC class

circuit

between the main circuit and

from the inverter's main circuit terminal

megger

ground terminals with a megger.

block, detach the control circuit terminal

block from the inverter, and remove the

jumper for switching the inverter's

The measured ground resistance

{

internal filter function. Subsequently,

measure the insulation resistance

must be 5MΩ or more.

between the ground terminal and the

jumper connecting all the following

terminals:

R, S, T, U, V, W, P, PD, N, RB, R0, and

T0

(2) Check screws and bolts for

{

Retighten loose screws and bolts.

There

must

be

no

abnormality

loosening.

found.

(3) Check each part for any trace of

{

Check visually.

There must be no abnormality

overheating.

found.

Connecting

(1) Check the conductors for

{

Check visually

conductors and

distortion.

There must be no abnormality

cables

(2) Check the cable insulations for

{

found.

damage.

Terminal block

Check the terminal blocks for

{

Check visually

There

must

be

no

abnormality

damage.

found.

Inverter circuit

Check the resistance between

Remove all cables from the

See Section 6.5, "Method of

Analog tester

and converter

terminals.

inverter's main circuit terminal block.

circuit (including

Use a tester (in 1Ω range mode) to

Checking

the

Inverter

and

resistors)

{

measure the following:

Converter

Circuits."

Standard

- Resistance between terminals R,

operating life of inverter circuit

S, and T and terminals P and N

until replacement: 106 cycles of

- Resistance between terminals U,

starting and stopping (*3)

V, and W and terminals P and N

Smoothing

(1) Check for liquid leak.

{

Check visually.

There must be no abnormality

Capacitance

capacitor

(2) Check that the relief valve does

found.

operating

life

until

meter

Target

not protrude or swell.

{

replacement: 10 years

(*1) (*3)

Relay

(1) Check that no fluttering sound is

Check by listening.

There

must

be

no

abnormality

generated during the relay

{

found.

operation.

(2) Check the contacts for damage.

{

Check visually.

There

must

be

no

abnormality

found.

Control

Operation

(1) While performing a unit

Measure the voltage between the

The inter-phase voltage balance

Digital

and

operation of the inverter, check

{

cables connected to the main circuit

must be as follows:

multimeter,

protective

the balance output voltage

terminals U, V, and W.

200 V class models: 4 V or less

rectifier

circuits

among the individual phases.

400 V class models: 8 V or less

instrument, and

(2) Carry out a sequential

Short-circuit or open the protective

An

error

must be

detected

voltmeter

protection operation test, and

{

circuit outputs as a simulation.

check the protective and display

according to the sequence.

circuits for any abnormality.

Cooling

Cooling fan

(1) Check for abnormal vibrations

{

Turn the fan manually during the

The

fan

must

rotate

smoothly.

system

and noise

inverter power-off status.

There must be no abnormality

(2) Check the joints for loosening.

Check visually.

found.

operating

life

until

Standard

{

replacement: 10 years

(*2) (*3)

Heat sink

Check for clogging.

{

Check visually.

The

heat

sink

must

not

be

clogged.

Display

Monitor

(1) Check that all LEDs light up

{

Check visually.

The LEDs must light up normally.

normally.

(2) Clean the monitor.

{

Clean the monitor with a rag.

Meter

Check that meter readings are

{

Check the meter readings on the

The

readings must

meet

the

Voltmeter and

normal.

panel.

standard and control values.

ammeter

Motor

General

(1) Check for abnormal vibrations

{

Check vibrations and noise visually,

There

must

be

no

abnormality

and noise.

by listening, and with physical

found.

senses.

(2) Check for unusual smells.

{

Check for any unusual smells

There

must

be

no

abnormality

caused by overheating or damage.

found.

Insulation

Check the ground resistance

Remove the cables from the

500 VDC class

resistance

between all motor terminals and the

inverter's main circuit terminals U, V,

megger

ground terminal with a megger.

and W, connect the motor wires (for

The measured ground resistance

{

three phases) with one another, and

must be 5MΩ or more.

measure the ground resistance

between the motor wires and the

ground terminal.

*1 The operating life of the smoothing capacitor is under the influence of the ambient temperature. Refer to Section 6.6, "Smoothing-Capacitor Life Curve," as a standard for the operating life until replacement.

*2 The operating life of the cooling fan varies depending on environmental conditions, including the ambient temperature and dust. Check the status of the cooling-fan operation during daily inspections.

*3 The standard operating life (number of years or operation cycles) and the data described in Section 6.6, "Smoothing-Capacitor Life Curve," are based on the expected design life, but they do not indicate the guaranteed life of any parts.

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