Synchronous motors in ELSM^® control mode

For operation of synchronous motors in the ELSM^® control mode, there are 2 modes, i.e. open-loop and closed-loop operation.

Open-loop operation is active when starting from idle state and below a transition speed. The transition speed is about 2% of the nominal speed. In this range, the available torque is limited. In open-loop control, the rated output current of the inverter is 1.5 times the standstill current I₀ of the connected motor, regardless of the load. It is therefore necessary to check whether the inverter can also provide this current at low output frequencies. Check whether the thermal characteristics of the motor are suitable for this. Permanent operation below the transition speed is not permitted.

Above this transition speed value, the drive is operated in closed-loop operation. In closed-loop control, the usable torque depends on the motor as well as on the motor-inverter combination.

The values for the transition speed, base speed and maximum dynamic torque in open-loop and closed-loop control can be found in the speed-torque characteristics. For motor/inverter characteristic curves, refer to the SEW‑EURODRIVE website.

The ELSM^® control mode allows dynamic use of the entire speed range of the drive. Reversing and moving through the speed 0 are also possible.

Do not configure the maximum speed higher than the rated speed of the motor.

Using the ELSM^® control mode for hoists and inclining tracks is not permitted.