Mitsubishi Electric FR-A700 Series, Technical Manual

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543
SELECTION
S
E
LECTION
3
3.7 Enclosure design
When an inverter enclosure is to be designed and
manufactured, heat generated by contained equipment,
etc., the environment of an operating place, and others
must be fully considered to determine the panel structure,
size and equipment layout. The inverter unit uses many semiconductor devices. To ensure higher reliability and
long period of operation, operate the inverter in the
ambient environment that completely satisfies the
equipment specifications.
3.7.1 Inverter installation environment
As the inverter installation environment should satisfy the
standard specifications indicated in the following table,
operation in any place that does not meet these conditions
not only deteriorates the performance and life of the
inverter, but also causes a failure. Refer to the following
points and take adequate measures.
* For the 160K or more and 185K or more, the
vibration is 2.9ms
2
or less
(1) Temperature
The permissible surrounding air temperature of the
inverter is between -10 and +50
. Always operate
the inverter within this temperature range. Operation
outside this range will considerably shorten the
service lives of the semiconductors, parts, capacitors
and others. Take the following measures so that the
surrounding air temperature of the inverter falls within
the specified range.
1) Measures against high temperature
(a) Use a forced ventilation system or similar
cooling system. (Refer to page 549)
(b) Install the panel in an air-conditioned electrical
room.
(c) Block direct sunlight.
(d) Provide a shield or similar plate to avoid direct
exposure to the radiated heat and wind of a
heat source.
(e) Ventilate the area around the panel well.
2) Measures against low temperature
(a) Provide a space heater in the enclosure.
(b) Keep the inverter power ON. (Keep the start
signal of the inverter OFF.)
3) Sudden temperature changes
(a) Select an installation place where
temperature does not change suddenly.
(b) Avoid installing the inverter near the air outlet
of an air conditioner.
(c) If temperature changes are caused by
opening/closing of a door, install the inverter
away from the door.
(2) Humidity
Normally operate the inverter within the 45 to 90%
range of the ambient humidity. Too high humidity will
pose problems of reduced insulation and metal
corrosion. On the other hand, too low humidity may
produce a through-air insulation breakdown. The
insulation distance specified in JEM1103 "Control
Equipment Insulator" is defined as humidity 45 to
85%.
1) Measures against high humidity
(a) Make the panel enclosed, and provide it with a
moisture absorber.
(b) Take dry air into the enclosure from outside.
(c) Provide a space heater in the enclosure.
2) Measures against low humidity
What is important in this condition is to blow air of
proper humidity into the enclosure from outside. It
is also important to discharge your body (static
electricity) before fitting or inspection of the unit,
and keep your body from contact with the parts
and patterns.
3) Measures against condensation
Condensation may occur if temperature in the
panel changes suddenly due to frequent power
ON/OFF switching or if atmospheric temperature
changes suddenly.
Condensation will cause insulation to be
deteriorated and corrosion to occur.
(a) Take the measures against high humidity in
1).
(b) Keep the inverter power ON (Keep the start
signal of the inverter OFF.)
(3) Dust, dirt, oil mist
Dust and dirt will cause such faults as poor contact of
contact points, reduced insulation or reduced cooling
effect due to moisture absorption of accumulated
dust and dirt, and in-panel temperature rise due to
clogged filter. In the atmosphere where conductive
powder floats, dust and dirt will cause such faults as
malfunction, deteriorated insulation and short circuit
in a short time.
Since oil mist will cause similar conditions, it is
necessary to take adequate measures.
Countermeasures
(a) Place in a totally enclosed enclosure.
Take measures if the in-enclosure
temperature rises.
(Refer to page 548, 549.)
Environmental standard specifications of inverter
Item Description
Surrounding air
temperature
-10 to +50 (non-freezing)
Ambient
humidity
90% RH maximum (non-condensing)
Atmosphere
Free from corrosive and explosive gases
Free from dust and dirt
Maximum
altitude
1000m or less
Vibration
5.9m/s
2
{0.6G} or less *
A700 F700