Version 3.05
| Optidrive Eco User Guide |
71
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11.7. Derating Information
Derating of the drive maximum continuous output current capacity is require when:
Operating at ambient temperature in excess of 40°C / 104°F (IP55 & IP66) or 50°C / 122°F (IP20).
Operating at Altitude in excess of 1000m/ 3281 ft.
Operation with Effective Switching Frequency higher than the minimum setting.
The following derating factors should be applied when operating drives outside of these conditions.
11.7.1. Derating for Ambient Temperature
Enclosure Type
Maximum Temperature
Without Derating
Derate by
Maximum Permissible
IP20
50°C / 122°F
N/A
50°C / 122°F
IP20 Frame Size 5
35°C / 95°F
1.1% per °C (1.8°F)
50°C / 122°F
IP55
40°C / 104°F
1.5% per °C (1.8°F)
50°C / 122°F
IP66
40°C / 104°F
2.5% per °C (1.8°F)
50°C / 122°F
11.7.2. Derating for Altitude
Enclosure Type
Maximum Temperature
Without Derating
Derate by
Maximum Permissible
IP20
1000m / 3281ft
1% per 100m / 328 ft
4000m / 13123 ft
IP55
1000m / 3281ft
1% per 100m / 328 ft
4000m / 13123 ft
IP66
1000m / 3281ft
1% per 100m / 328 ft
4000m / 13123 ft
11.7.3. Derating for Switching Frequency
Enclosure
Type
Switching Frequency (Where available)
Frame
Size
4kHz
8kHz
10kHz
12kHz
14kHz
16kHz
18kHz
20kHz
24kHz
32kHz
IP66
2
N/A
N/A
0%
0%
0%
0%
0%
0%
N/A
N/A
3
N/A
N/A
0%
0%
0%
6%
N/A
N/A
N/A
N/A
IP55
4
N/A
N/A
0%
0%
12%
23%
33%
41%
N/A
N/A
5
N/A
N/A
0%
0%
11%
23%
36%
42%
N/A
N/A
6
0%
16%
N/A
28%
N/A
39%
N/A
N/A
N/A
N/A
7
0%
12%
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
IP20
2
N/A
N/A
0%
14%
23%
32%
37%
43%
N/A
N/A
3
N/A
N/A
0%
2%
13%
19%
25%
35%
N/A
N/A
4
N/A
N/A
0%
15%
13%
39%
52%
62%
N/A
N/A
5
N/A
N/A
0%
3%
9%
14%
19%
24%
N/A
N/A
6
0%
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
8
0%
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
11.7.4. Example of Applying Derating Factors
A 4kW, IP66 drive is to be used at an altitude of 2000 metres above sea level, with 16 kHz 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 (if any), 16 kHz, 0% derating.
Now, apply the derating for higher ambient temperature, 2.5% per °C above 40°C = 5 x 2.5% = 12.5%
9.5 Amps x 87.5% = 8.3 Amps.
Now apply the derating for altitude above 1000 metres, 1% per 100m above 1000m = 10 x 1% = 10%
8.3 Amps x 90% = 7.5 Amps continuous current available.
If the required motor current exceeds this level, it will be necessary to either:
Reduce the switching frequency selected; or
Use a higher power rated drive and repeat the calculation to ensure sufficient output current is available.
11
Technical Data
