7
Installation of the inverter and enclosure
design
1
(1) Temperature
The permissible surrounding air temperature of the inverter is between -10
°C
and +50
°C
. 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
• Use a forced ventilation system or similar cooling system.
(Refer to page 9.)
• Install the enclosure in an air-conditioned electrical chamber.
• Block direct sunlight.
• Provide a shield or similar plate to avoid direct exposure to the radiated heat and wind of a heat source.
• Ventilate the area around the enclosure well.
2) Measures against low temperature
• Provide a space heater in the enclosure.
• Do not power off the inverter. (Keep the start signal of the inverter off.)
3) Sudden temperature changes
• Select an installation place where temperature does not change suddenly.
• Avoid installing the inverter near the air outlet of an air conditioner.
• 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 spatial electrical
breakdown. The insulation distance specified in JEM1103 "Control Equipment Insulator" is defined as humidity 45 to
85%.
1) Measures against high humidity
• Make the enclosure enclosed, and provide it with a hygroscopic agent.
• Take dry air into the enclosure from outside.
• Provide a space heater in the enclosure.
2) Measures against low humidity
What is important in fitting or inspection of the unit in this status is to discharge your body (static electricity)
beforehand and keep your body from contact with the parts and patterns, besides blowing air of proper humidity into
the enclosure from outside.
3) Measures against condensation
Condensation may occur if frequent operation stops change the in-enclosure temperature suddenly or if the outside-
air temperature changes suddenly.
Condensation causes such faults as reduced insulation and corrosion.
• Take the measures against high humidity in 1).
• Do not power off the inverter. (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-enclosure 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
• Place in a totally enclosed enclosure.
Take measures if the in-enclosure temperature rises.
(Refer to page 9.)
• Purge air.
Pump clean air from outside to make the in-enclosure pressure higher than the outside-air pressure.
Summary of Contents for FR-A741-11K
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