5.3.5 Cooling Fans
All drives in this size range are equipped with cooling fans
to provide airow for temperature regulation. Each fan has
tachometer feedback to the control card to conrm that
the fan is operating correctly. On/oîš‚ and speed control of
the fans is provided to reduce overall acoustic noise and
extend the life of the fans.
Cooling fans in D-sized and E-sized drives include:
•
Mixing fans.
•
Heat sink fans.
•
Door fans (IP21/IP54).
•
Top fans (IP00/IP20).
Mixing fans
In D-sized units, the mixing fan operates any time the
drive is powered on. The fan is powered by 24 V DC from
the main switch mode power supply, and runs on DC
voltage from the power card. The mixing fan is mounted
under the input plate.
In E-sized units, the operation of the mixing fans is
controlled and the fans run only when commanded. The
fans are powered by 48 V DC supply on the power card. In
E1h/E3h drives, the 2 mixing fans are mounted on the
input plate. In E2h/E4h drives, 1 mixing fan is mounted on
the input plate, and 1 fan is mounted below the power
card near the IGBT modules.
Heat sink fans
D-sized drives have 1 heat sink fan in the back channel.
The heat sink fan runs on DC voltage from the power card.
It is powered by 48 V DC from a dedicated switch mode
power supply on the power card.
E-sized drives include 3 heat sink fans in the back channel.
The heat sink fans are powered from the fan power card.
Door fans
D-sized drives in IP21/IP54 enclosures have door fans. The
fans are powered by 48 V DC from a dedicated switch
mode power supply on the power card.
E-sized drives in IP21/IP54 enclosures have 2 fans in the
door. These door fans are powered from the fan power
card.
Top fans
D-sized units in IP00/IP20 enclosures have a fan mounted
to the top of the unit for more cooling. The top fan is
powered by 48 V DC from a dedicated switch mode power
supply on the power card.
E-sized drives in IP00/IP20 enclosures include 2 fans
mounted on the top of the drive. The top fans are
powered from the fan power card.
Fan activation
The following conditions activate the fans:
•
Output current greater than 40% of nominal.
•
High IGBT temperature.
•
Low IGBT temperature.
•
High control card temperature.
•
DC hold active.
•
DC brake active.
•
Dynamic brake circuit active.
•
During pre-magnetization of the motor.
•
AMA in progress.
In addition to these conditions, the fans are always started
shortly after mains input power is applied to the drive.
Once fans are started, they run briey while the system
veries that they are functioning properly.
5.3.6 Fan Speed Control
The following conditions cause the fans to run at full
speed:
•
Low IGBT temperature.
•
Active DC hold.
•
Active DC brake.
•
Active dynamic brake circuit.
•
Pre-magnetization of the motor.
•
AMA in progress.
Fan speeds
The fans in E-sized drives have the following maximum
speeds.
•
Mixing fans: 10000 rpm
•
Heat sink fans: 7800 rpm
•
Door fans: 6500 rpm
•
Top fans: 6500 rpm
Mixing fan
In D-sized drives, the mixing fan runs at full speed
whenever the drive has power. In E-sized drives, the fan is
controlled and runs only when commanded.
Heat sink fan
The IGBT temperature and the output current determine
the speed of the heat sink fan. The fan runs at the higher
of the 2 settings.
In D-sized drives, if the output is greater than 84% of the
nominal current, the fan runs at 100% speed. If the output
current is less than 40% of the nominal current, the fan
turns oîš‚. When the IGBT temperature reaches the fan turn-
on temperature, the fan starts and runs at its minimum
speed. As the IGBT temperature increases, the fan speed
increases. When the IGBT temperature reaches the fan
maximum speed temperature, the fan is running at 100%
speed. As the IGBT temperature decreases, the fan speed
Internal Drive Operation Service Guide
MG94A502 Danfoss A/S © 02/2019 All rights reserved. 57
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