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Protective functions – MITSUBISHI ELECTRIC FR-A500L User Manual

Page 47

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PROTECTIVE FUNCTIONS

36

Daily and Periodic Inspection

Interval

Periodic

Area of

Inspec-

tion

Inspection

Item

Description

Daily

1

year

2

years

Method

Criterion

Instrument

Inverter
module,
Converter
module

Check resistance
across terminals.

{

Disconnect cables
from inverter and
measure across
terminals R, S, T, P, N
and U, V, W, P, N

1

,

L

2

, L

3,

+, -, and U, V,

W, +, -> with tester
range of 100

.

(See the following
pages)

Analog tester

Smoothing
capacitor

(1) Check for liquid

leakage.

(2) Check for safety

valve projection and
bulge.

(3) Measure

electrostatic
capacity.

{

{

{

(1), (2) Visual check.
(3) Measure with

capacity meter.

(1), (2) No fault.
(3) 85% or more
of rated capacity.

Capacity
meter

Relay

(1) Check for chatter

during operation.

(2) Check for rough

surface on contacts.

{

{

(1) Auditory check.
(2) Visual check.

(1) No fault.
(2) No fault.

Main
circuit

Resistor

(1) Check for crack in

resistor insulation.

(2) Check for open

cable.

{

{

(1) Visual check.

Cement resistor,
wire-wound
resistor.

(2) Disconnect one

end and measure
with tester.

(1) No fault.
(2) Error should

be within

±

10% of

indicated
resistance
value.

Tester, digital
multimeter

Control
circuit
Protective
circuit

Operation
check

(1) Check balance of

output voltages
across phases with
inverter operated
independently.

(2) Perform sequence

protective operation
test to make sure of
no fault in protective
and display circuits.

{

{

(1) Measure voltage

across inverter
output terminals
U-V-W.

(2) Simulatively

connect or
disconnect inverter
protective circuit
output terminals.

(1) Phase-to-

phase voltage
balance within
8V for 400V.

(2) Fault must

occur because
of sequence.

Digital
multimeter,
rectifier type
voltmeter

Cooling fan

(1) Check for unusual

vibration and noise.

(2) Check for loose

connection.

{

{

(1) Turn by hand with

power off.

(2) Re-tighten

(1) Smooth

rotation.

(2) No fault.

Cooling
system

Cooling fan
power
supply

Is the power supply's
output voltage correct?

{

Measure with a tester. 24V 2.4V

Tester

Display

(1) Check if LED lamp

is blown.

(2) Clean.

{

{

(1) Light indicator

lamps on panel.

(2) Clean with rag.

(1) Check that

lamps are lit.

Display

Meter

Check that reading is
normal.

{

Check reading of
meters on panel.

Must satisfy
specified and
management
values.

Voltmeter,
ammeter, etc.

General

(1) Check for unusual

vibration and noise.

(2) Check for unusual

odor.

{

{

(1) Auditory, sensory,

visual checks.

(2) Check for unusual

odor due to
overheating,
damage, etc.

(1), (2) No fault.

Motor

Insulation
resistance

(1) Check with megger

(across terminals
and ground
terminal).

{

(1) Disconnect cables

from U, V, W,
including motor
cables.

(1) 5M

or more

500V megger