Version 2.04
| Optidrive ODP-2 Solar Pump User Guide |
67
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11.3. 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 for enclosed drives (non UL approved)
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:
11.3.1. Derating for Ambient Temperature
Enclosure Type
Maximum Temperature
Without Derating
(UL Approved)
Derate by
Maximum Permissible
Operating Ambient
Temperature with Derating
(Non UL Approved)
IP20
50°C / 122°F
N/A
50°C
IP55
40°C / 104°F
1.5% per °C (1.8°F)
50°C
IP66
40°C / 104°F
2.5% per °C (1.8°F)
50°C
11.3.2. Derating for Altitude
Enclosure Type
Maximum Altitude
Without Derating
Derate by
Maximum
Permssable
(UL Approved)
Maximum
Permssable
(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
11.3.3. Derating for Swicthing 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%
11.3.4. 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.
11
Technical Data
