Two Speed Electric Motors

TAP WOUND / DAHLANDER Variable Torque 4/2 - 8/4 - 12/6 POLES

Tap Wound / Variable Torque / Fan Rated two speed electric motors are ex stock at TEC electric motors. Two speed electric motors by their application reduce energy usage by giving the user the lower speed and hence lower power option, more closely matching actual demand. Variable Torque 2 speed motors are best suited to a Fan or Pump applications. The constant torque 2 speed motor is best suited to crane and machine tool applications. TEC motors are able to offer Constant Torque if required.

TEC are also able to supply to correct control gear – Please see our Inverter and Starter Section!

Dahlander, pole changing or tap wound overview:

Comprises a single winding with two stator winding polarities which gives the ability to change motor speeds by varying the connections. Polarity speed ratios of 2:1 are obtained by bringing out centre tapped leads from the winding and double starring the high speed configuration.  This means that to engage the low speed a simple three phase feed is required.  However, when switching to high speed, control gear must put the low speed terminals into the star configuration.  Because the motor only has a single winding, this is achieved simply and cost-effectively by using three simple contactors!

Two Speed Motor or Frequency Inverter ?

The sophisticated frequency inverter can be over kill for many applications partially in simple applications such as fan and pump duties. If all that is required is HIGH and LOW output the two speed electric motor are:

• Generally cost less than Frequency Inverters
• Very Simple
• Efficient
• Easily installed and commissioned
• Attract capital allowances from the Carbon Trust same as Eff 1 motors
• Are available in EFF1

Standard Motor Specifications

• Siluminium die cast finned frames cast feet
• Totally enclosed fan cooled
• 132 – 280 frame are cast framed with detachable feet
• Mountings B3, B5, B35, (B14 and B34 up to 132 Frame)
• Metal Terminal Box
• S1 Duty
• -20 deg to 40 deg – 1000m above sea level
• Voltage 230/400 +/- 10% Delta / Star up to 2.2 kW 400/690 +/- 10% Delta / Star from 3 kW
• Available in EFF1  (EU / CEMEP)
• IP55
• Insulation Class F (Rise B)
• Colour Ral (5010)

Optional Features on Request

• Special voltages
• Specially designed shaft
• Heaters 110V and 240V DC
• Thermal Protective Klixons
• Drip cover (canopy) for shaft down applications
• Special epoxy painting
• Double Shafted
• Directional drain holes
• IP up grades
• Tropicalised windings

Please veiw our Specials section for more details!