If actuators are run using a “Direct On-Line” (DOL) starting method then they can only be roughly synchronised for speed and position. Small differences in motor speed and actuator loading may cause the units to get out of synchronisation. The units can therefore not be guaranteed to run in synchronisation. For exact synchronisation a closed loop control system is recommended. This can be achieved using AC motors with AC inverters or Servo motors with a matched drive as part of a control solution. The speed and position feedback is typically provided by an incremental or absolute encoder. For further advice consult Power Jacks.

Alternatively EMA Linear Actuators and Rolaram Linear Actuators can be manufactured so that they can be mechanically connected with drive shafts with a single motor driving the connected unit.