Nidec Leroy-Somer Powerdrive MD Smart, Руководство по интеграции

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GENERAL INFORMATION
Powerdrive MD Smart Integration Guide
5751 en - 2021.10 / e
GENERAL
INFORMA
TION
1.4.3 - Internal loss management
Losses generated inside the enclosure are from power and passive components. In order to evacuate them several methods are
possible:
• Extractors and filters: when the room temperature is always below the required enclosure temperature and the enclosure is in a
low-pollution environment, fans are the easiest and most efficient solution.
While operating, fans generate an overpressure in the electrical box. The filters in the door must be positioned in the lower part
and the fan in the upper part or vice versa.
• Air conditioners:
if the environment does not allow sufficiently filtered air to flow between the outside and inside of the enclosure,
thus ensuring the integrity of the components, then consideration will be given to a waterproof and air-conditioned solution.
Where the temperature required in the electrical box is to be at or below the ambient temperature and/or the ambient air is too
polluted, it is preferable to use air conditioner(s).
When air conditioners are used to cool the air in the enclosures, it should be noted that the moisture from the air expelled into the
enclosure increases due to the cooling of the air conditioner and may fall below the dew point (the temperature at which the water
vapour contained in the air condenses into water). It is therefore essential to keep the moisture inside the enclosure at a higher
level in order to avoid any risk of premature material degradation.
Example:
For a temperature Tair = 35°C and a humidity of 60%.
At intersection A on the graph, the dew point temperature
is 26°C.
The temperature inside the enclosure must therefore not
be less than 26°C.
• Air/water heat exchangers: when the ambient air is
too aggressive for the use of standard air conditioners
and a high IP protection rating is required, then it is
preferable to use an exchanger(s). In addition, the air/
water exchanger does not dissipate heat losses from the
electrical box in the environment where the enclosure is
located, as losses are discharged into the heat transfer
fluid.
Formula for calculating air flow rate
V = 3.1 x P
V
[m
3
/h]
∆T
V[m
3
/h] : filter fan air flow rate
PV[Watt] : loss of dissipation (thermal power generated in an enclosure by
loss of dissipation of components)
∆T : difference between ambient and indoor air temperature
A