10.5.2. Derating for Altitude
Enclosure Type
Maximum Altitude
Without Derating
Derate by
Maximum
Permissible
(UL Approved)
Maximum
Permissible
(Non-UL Approved)
IP20
1000m / 3281ft
1% per 100m / 328 ft
2000m / 6562 ft
4000m / 13123 ft
IP55
1000m / 3281ft
1% per 100m / 328 ft
2000m / 6562 ft
4000m / 13123 ft
IP66
1000m / 3281ft
1% per 100m / 328 ft
2000m / 6562 ft
4000m / 13123 ft
10.5.3. Derating for Switching Frequency
Enclosure
Type
Switching Frequency (Where available)
4kHz
8kHz
12kHz
16kHz
24kHz
32kHz
IP20
N/A
N/A
20%
30%
40%
50%
IP55
N/A
10%
10%
15%
25%
N/A
IP66
N/A
10%
25%
35%
50%
50%
10.5.4. Example of applying Derating Factors
A 4kW, IP66 drive is to be used at an altitude of 2000 metres above sea level, with 12kHz switching frequency and 45°C ambient
temperature.
From the table above, we can see that the rated current of the drive is 9.5 Amps at 40°C,
Firstly, apply the switching frequency derating, 12kHz, 25% derating
9.5 Amps x 75% = 7.1 Amps
Now, apply the derating for higher ambient temperature, 2.5% per °C above 40°C = 5 x 2.5% = 12.5%
7.1 Amps x 87.5% = 6.2 Amps
Now apply the derating for altitude above 1000 metres, 1% per 100m above 1000m = 10 x 1% = 10%
7.9 Amps x 90% = 5.5 Amps continuous current available.
If the required motor current exceeds this level, it will be necessary to either:
Reduce the switching frequency selected.
Use a higher power rated drive and repeat the calculation to ensure sufficient output current is available.
10.6. Internal EMC Filter and Varistors – Disconnection Procedure
10.6.1. IP20 Drive Models
All Optidrive P2 models provide a simple method to disconnect the internal EMC filter and surge protection varistors by fully removing
the screws shown below. This should only be carried out where necessary, for example in cases such as IT or ungrounded supplies,
where the phase to ground voltage can exceed the phase to phase voltage.
The EMC filter disconnect screw is labelled “EMC“.
The surge protection varistors disconnect screw is clearly labelled “VAR”.
Frame Sizes 2 & 3
The EMC Filter and
Varistor disconnect screws
are located on the left
side of the product when
viewed from the front.
Remove both screws
completely
76
| Optidrive P2 User Guide |
Version 3.04
www.invertekdrives.com
10
Technical Data
