NOTE!
A door fan 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). If the VLT is the only heat generating component in the enclosure, the minimum airflow required at an ambient temperature
of 113°F [45°C] for the D3 and D4 drives is 391 m
3
/h (230 cfm). The minimum airflow required at an ambient temperature of 113°F
[45°C] for the E2 drive is 782 m
3
/h (460 cfm).
Airflow
The necessary airflow over the heatsink must be ensured. The flow rate is shown below.
Enclosure protection
Frame size
Door fan/Top fan airflow
Airflow over heatsink
IP21 / NEMA 1
IP54 / NEMA 12
D1 and D2
170 m
3
/h (100 cfm)
765 m
3
/h (450 cfm)
E1 P250T5, P355T7, P400T7
340 m
3
/h (200 cfm)
1105 m
3
/h (650 cfm)
E1 P315-P400T5, P500-P560T7
340 m
3
/h (200 cfm)
1445 m
3
/h (850 cfm)
IP21 / NEMA 1
F1, F2, F3 and F4
700 m
3
/h (412 cfm)*
985 m
3
/h (580 cfm)
IP54 / NEMA 12
F1, F2, F3 and F4
525 m
3
/h (309 cfm)*
985 m
3
/h (580 cfm)
IP00 / Chassis
D3 and D4
255 m
3
/h (150 cfm)
765 m
3
/h (450 cfm)
E2 P250T5, P355T7, P400T7
340 m
3
/h (200 cfm)
1105 m
3
/h (650 cfm)
E2 P315-P400T5, P500-P560T7
340 m
3
/h (200 cfm)
1445 m
3
/h (850 cfm)
* Airflow per fan. Frame size F contain multiple fans.
Table 7.3: Heatsink Air Flow
NOTE!
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).
Once the fan is started, it will run for a minimum of 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
adjustable frequency drive according to the pressure drop.
Figure 7.27: D frame Derating vs. Pressure Change
Drive air flow: 450 cfm (765 m3/h)
FC 300 Design Guide
7 Mechanical Installation - Frame size D, E and
F
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
7-23
7