Flat-frame motors

Exemplary design

Brief description

AKH flat-frame motors are AC asynchronous motors in an especially flat and compact design. The motors are characterized by a high power density and high energy efficiency.


Amongst other things, these robust motors are found in band and circular saw systems in sawmills. With assembling of partly multiple, larger saw blades directly on the shaft of the motor, highly efficient systems are realized worldwide with these motors.

Flat-frame motors of IE2 and IE3

The higher efficiency class is achieved without the need of higher motor sizes.

These motors are used for high efficiency saw mills worldwide.


  • Shaft height: 75 to 190 mm
  • Power: up to 132 kW
  • Speed range: up to 12.000 rpm
  • Duty cycle: S1
  • Cooling: IC 411 (self-ventilated)
  • Voltage: 400 V / 50 Hz
  • Insulation class: F
  • Mounting: IM B35
  • Degree of protection: IP 54
  • Vibration severity grade: A
  • Ambient temperature: 20 to 40 °C

Details of standard design

  • Shaft end made from C-45
  • Balancing with half key
  • Material of motor housing made from aluminium alloy or cast iron
  • bearing shields made from cast iron or steel
  • Lifetime lubricated rolling bearings
  • Primer RAL 7031

Options of electrical design

  • Increased rated power for intermittent operation S6
  • Efficiency classes IE 2, IE 3
  • Optimized for frequency converter operation
  • With external fan
  • Dimensioning as 2, 4 or 6- pole motors
  • Pole-changing motors 4/2 or 8/4–pole
  • Special voltages and -frequencies
  • Insulation class H
  • Higher ambient temperature and installation altitude
  • Winding temperature monitoring by thermo switch, PTC resistor or Pt100
  • Anti-condensation heating

Options of mechanical design

  • Other mountings acc. to IEC 60034-7
  • Manual or automatic regreasing device
  • Backlash-free or special high speed spindle bearings
  • Special bearings for high radial and axial loads (by milling cutter e.g.)
  • Electrically insulated bearings
  • Protection class IP 55, IP 56 with labyrinth seal
  • Hollow shaft, rock shaft with tool holders
  • Vibration severity grade: B
  • Humidity- and tropic proofing
  • Housing, bearing shields and terminal box made from ductile cast iron or steel
  • Different lacquer qualities , RAL- color at customers option

Options of built-on components

  • Holding brake (manual release, wear monitoring)
  • Optical or magnetic speed sensors
  • Backstop
  • chucking appliance and tool changer

Options of certificates, special approvals, e.g.

  • GOST
  • Germanischer Lloyd
  • Diverse works Standards
  • etc.

Example: motor HENK7/1G-02

  • Voltage: 380 / 660 V
  • Power: 80 kW S1 (continuous operation)
  • Speed range: 2.965 rpm
  • Efficiency classes IE 2: 94,0 %
  • Shaft height: 190 mm

Application-specific technical details

  • according to efficiency classes IE 2
  • Dimensioned for special voltages
  • Hollow shaft and rock shaft according to customer specification with attached parts for built-on saw blades
  • Backlash-free double- spindle bearings drive end side
  • Manual regreasing device

Flat-frame Motors