Separately driven fans for motors

Why forced ventilation?

DSC_2178In modern drive technology the three-phase asynchronous motor is becoming increasingly important. It is an almost maintenance-free unit and has a fan on the opposite side to the drive shaft, which supplies the motor sufficient with cooling air at its rated speed .

Durch den Einsatz von Frequenzumrichtern an den Motoren wird die Drehzahl des Motors stufenlos verstellt. Dadurch wird der Motor nicht mehr ausreichend durch den Eigenlüfter mit Kühlluft versorgt. Ein Fremdlüfteraggregat übernimmt diese Aufgabe.

The use of frequency inverters with the motors the motor speed is continuously adjusted. Thus, the motor is no longer adequately supplied with cooling air by the integrated fan. A forced ventilation unit takes over this task.

In the following conditions, a forced ventilation unit should be used:

  • Operation of a motor with frequency inverter
  • High torque on low speed
  • Use of an encoder system (the integrated fan is removed)
  • Drives with high starting frequency
  • Inverter drives with a setting range> 1:20
  • Inverter drives that have to generate rated torque even at low speeds or even at standstill
  • Drives with additional flywheel mass
  • Drives that are operated above the rated speed (high fan noise)

Long or short version?

The forced ventilation units are available in two lengths:

  • If no encoder system is installed, so the short length may be used. This is easily done, remove the integrated fan from the motor shaft and screw the cover to the motor housing.
  • If an encoder system (incremental encoder / SinCos encoder etc.) is installed, the long version is the right one. The electrical connection is made at the terminal box of the external fan unit.

The power supply is 400 VAC 3 phase, 50 / 60Hz or the external fan up to size 200 can also be operated with 230 VAC 1ph 50/60 Hz. Other supply voltages are available on request.

Technical details:

  • Electrical connection in the terminal box
  • Delivery is either primed or painted (when ordering please indicate color)
  • Protection IP 55
  • CE sign and construction according to UL
  • Short lead times
  • Power supply single and three phase, 230 VAC and 400 VAC (up to size 200)


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EPA_Forced_ventilation_unit FL_Brochure.pdf1.56 M