4.3.6 Cooling and Airflow
Cooling
Cooling can be obtained in different ways, by using the
cooling ducts in the bottom and the top of the unit, by
taking air in and out the back of the unit or by combining
the cooling possibilities.
Back cooling
The backchannel air can also be ventilated in and out the
back of a Rittal TS8 enclosure. This offers a solution where
the backchannel could take air from outside the facility
and return the heat loses outside the facility thus reducing
air-conditioning requirements.
NOTE
A door fan(s) is required on the enclosure to remove the
heat losses not contained in the backchannel of the drive
and any additional losses generated from other
components installed inside the enclosure. The total
required air flow must be calculated so that the
appropriate fans can be selected. Some enclosure
manufacturers offer software for performing the
calculations (i.e. Rittal Therm software).
Airflow
The necessary airflow over the heat sink must be secured.
The flow rate is shown in Table 4.10.
Enclosure protection
Frame size
Door fan(s) / Top fan airflow
Total airflow of multiple fans
Heatsink fan(s)
Total airflow of multiple fans
IP21 / NEMA 1
IP54 / NEMA 12
D13
510 m
3
/h (300 cfm) 2295 m
3
/h (1350 cfm)
E9 P250
680 m
3
/h (400 cfm) 2635 m
3
/h (1550 cfm)
E9 P315-P400
680 m
3
/h (400 cfm) 2975 m
3
/h (1750 cfm)
IP21 / NEMA 1 F18
4900 m
3
/h (2884 cfm) 6895 m
3
/h (4060 cfm)
Table 4.10 Heatsink Air Flow
NOTE
For the drive section, the fan runs for the following
reasons:
1. AMA
2. DC Hold
3. Pre-Mag
4. DC Brake
5. 60% of nominal current is exceeded
6. Specific heatsink temperature exceeded (power
size dependent)
7. Specific Power Card ambient temperature
exceeded (power size dependent)
8. Specific Control Card ambient temperature
exceeded
Once the fan is started it will run for minimum 10 minutes.
NOTE
For the active filter, the fan runs for the following reasons:
1. Active filter running
2. Active filter not running, but mains current
exceeding limit (power size dependent)
3. Specific heatsink temperature exceeded (power
size dependent)
4. Specific Power Card ambient temperature
exceeded (power size dependent)
5. Specific Control Card ambient temperature
exceeded
Once the fan is started it will run for minimum 10 minutes.
External ducts
If additional duct work is added externally to the Rittal
cabinet the pressure drop in the ducting must be
calculated. Use the charts below to derate the frequency
converter according to the pressure drop.
How to Install VLT Automation Low Harmonic Drive Operating Instructions
28 MG34O202 - VLT
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