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Connecting Two Motors to One Drive

Two Motors Can Be Mechanically Connected to a single Drive

In this example DDL motors are used. However, linear, rotary, and permanent magnet motors also apply.

  • The motors must be identical in electrical characteristics
  • One of these motors will have to have an adjustment for phase matching between the two
  • The parallel combination of resistance and inductance must be used for the motor file in the drive

Two DDL Motors

Two DDL Motors.PNG

Further Requirements

  • You must have greater than ½ pole adjustment in the motor armature to ensure alignment. For instance, in a linear motor with 32mm pitch, you would need 16 mm of adjustment if the pitch was not already taken into account.
  • For a rotary motor, take the number of pole pairs and divide by 360 degrees to ensure that you can adjust each motor within the phases.


  • The slotted holes in the previous drawing show that armature #2 can be moved relative to its relationship with Armature #1
  • Using an oscilloscope with at least two channels, manually move the motor in either direction adjust the phase relationship for the two identical phases of each armature so that there is no phase difference between the two.

Alignment of BEMF Slightly Out

BEMF Align.jpg

Alignment Details

  • The previous picture was taken with two linear armatures being aligned.
  • The channel #1 was Phase A referenced to Phase B of motor armature #1
  • The channel #2 is Phase A referenced to Phase B or motor armature #2.
  • Adjust Armature #2 in the drawing example for 0 degrees phase shift or as close as possible.