34 Unidrive M / HS Frame 7 to 10 Power Installation Guide
Issue Number: 5
3.6 Enclosure design and drive ambient temperature
Drive derating is required for operation in high ambient temperatures
Totally enclosing or through panel mounting the drive in either a sealed cabinet (no airflow) or in a
well ventilated cabinet makes a significant difference on drive cooling.
The chosen method affects the ambient temperature value (T
rate
) which should be used for any
necessary derating to ensure sufficient cooling for the whole of the drive.
The ambient temperature for the four different combinations is defined below:
1. Totally enclosed with no air flow (<2 m/s) over the drive
T
rate
= T
int
+ 5 °C
2. Totally enclosed with air flow (>2 m/s) over the drive
T
rate
= T
int
3. Through panel mounted with no airflow (<2 m/s) over the drive
T
rate
= the greater of T
ext
+5 °C, or T
int
4. Through panel mounted with air flow (>2 m/s) over the drive
T
rate
= the greater of T
ext
or T
int
Where:
T
ext
= Temperature outside the cabinet
T
int
= Temperature inside the cabinet
T
rate
= Temperature used to select current rating from tables in Chapter 5 Technical data on
page 78.
3.7 Heatsink fan operation
The drive is ventilated by an internal heatsink mounted fan. The fan housing forms a baffle plate,
channelling the air through the heatsink chamber. Thus, regardless of mounting method (surface
mounting or through-panel mounting), the installing of additional baffle plates is not required.
Ensure the minimum clearances around the drive are maintained to allow air to flow freely.
The heatsink fan on all sizes is a variable speed fan. The drive controls the speed at which the fan
runs based on the temperature of the heatsink and the drive's thermal model system. The maximum
speed at which the fan operates can be limited in Pr 06.045. This could incur an output current
derating. Size 7 to 10 are also fitted with a variable speed fan to ventilate the capacitor bank. Refer to
section 3.11 Routine maintenance on page 45 for information on fan removal.
Unidrive M frame7 to 10 Power Installation Guide issue5.book Page 34 Tuesday, May 24, 2016 11:52 AM
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