Optidrive P2 Elevator User Guide V2.30
69
Technical Data
www.InvertekDrives.com
Derating Information
Derating of the drive maximum continuous output current capacity is required 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
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
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
Derating for Switching Frequency
Switching Frequency (Where available)
Enclosure Type
4kHz
8kHz
12kHz
16kHz
24kHz
32kHz
IP20
N/A
N/A
20%
30%
40%
50%
IP55
N/A
10%
10%
15%
25%
N/A
Example of applying Derating Factors
An 11kW, 380-480V IP55 drive is to be used at an altitude of 2000 metres above sea level, with 12 kHz switching frequency and 45°C ambient
temperature.
From the Output and Current ratings table 18.3.3, we can see that the rated current of the drive is 24 Amps at 40°C,
1.
Apply the switching frequency derating, 12kHz, 10% derating : 24 Amps x 90% = 21.6 Amps
2.
Now, apply the derating for higher ambient temperature, 1.5% per °C above 40°C :
a.
5 x 1.5% = 7.5%
b.
21.6 Amps x 92.5% = 20 Amps
3.
Now apply the derating for altitude above 1000 metres, 1% per 100m above 1000m :
a.
= 10 x 1% = 10%
b.
20 Amps x 90% = 18 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.
