Instruction Manual

3.3.5 Cooling Fans
All frequency converters in this size range are equipped with cooling fans to provide airflow along the heatsinks and within the enclosures. All fans are powered
by mains voltage which is stepped down by autotransformers and regulated to 200 or 230 VAC by circuitry provided on the power cards. On/off and high/low
speed control of the fans is provided to reduce overall acoustical noise and extend the life of the fans.
Fans are activated by the following causes:
60% of nominal current exceeded
Specific heatsink temperature exceeded (power size dependent)
Specific power card ambient temperature exceeded
Specific control card ambient temperature exceeded
DC hold active
DC brake active
Pre-magnetization of the motor
Automatic motor adaptation in progress
Regardless of the heatsink temperature, the fans are started shortly after main input power is applied to the frequency converter.
Once fans are started, they will run for a minimum of 10 minutes.
3.3.6 Fan Speed Control
The cooling fans are controlled with sensor feedback which regulates fan operation and speed control as described below.
• IGBT thermal sensor measured temperature. The fan can be off, low speed, or high speed based on this temperature.
IGBT Thermal Sensor Temperature
Fan turn ON low speed
45° C
Fan low speed to high speed
50° C
Fan high speed to low speed
40° C
Fan turn OFF from low speed
30° C
Table 3.1: IGBT Thermal Sensor
• Power card ambient temperature sensor measured temperature. The fan can be off or high speed based on this temperature.
Power Card Ambient Temperature
Fan turn ON to high speed
45° C
Fan turn OFF from high speed
40° C
Fan turn ON to high speed
<10° C
Table 3.2: Power Card Ambient Temperature Sensor
• Control card thermal sensor measured temperature. The fan can be off or low speed based on this temperature.
Control Card Ambient Temperature
Fan turn ON to low speed
55° C
Fan turn OFF from low speed
45° C
Table 3.3: Control Card Thermal Sensor
• Output current value. If the output current is greater than 60% of rated current, the fan will turn on low speed.
High Power Service Manual for Unit Sizes 6x
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