It is possible, but with conditions. Motors fed from one inverter all run at the same frequency and therefore at roughly the same speed. This solution is usually used for small fans doing the same job, groups of roller conveyors or pumps running in parallel.

  • Control mode: The inverter runs in scalar (V/f) mode. Sensorless vector control works on the parameters of a single motor, so it is generally not used with several motors.
  • Current: The inverter's continuous output current must cover the sum of all motor nameplate currents with a margin.
  • Protection: The inverter cannot protect the motors individually; each motor needs its own thermal protection or motor protection circuit breaker.
  • Switching in: Adding a motor to the output of a running inverter creates a current surge; the motors should start together or the inverter should be sized for this.
  • Cable: Total cable length increases capacitive current; the need for a filter is assessed on the total length.

If the motors are to run at different speeds or stop and start independently, using a separate inverter for each motor gives a better result.