Inverter Supply

MS,YDSA,YDSC series are designed to be supplied by inverter.
These motors can be driven up to the rated frequency (50Hz) with supply voltage proportional to the frequency. (See diagr. 1), at higher frequencies they can be supplied at constant voltage

By the type of supply shown in diagr. 1, the flux created by the stator windings will be constant from 0 frequency to 50 Hz frequency, at frequencies higher than 50 Hz, the flux will be lower than the maximum nominal value.

Note: For low frequencies (0~10Hz.) due to the voltage drops, in order to keep the flux constant, the supply voltage should be slightly increased. This voltage increase depends both on the motor type and on the inverter type.

Consequently the motors in standard execution (self ventilating code IC411) are able to run at constant torque between 40 and 50 Hz and at constant power in the section included between 50 and indicated value on the refereaced.

Upon request, the MS,YDSA,YDSC series motors can be equipped with an auxiliary fan (code IC 416), in this case they can supply a constant torque between 0 and 50 Hz and a constant power in the section included between 50 and indicate dvalue on the diagram 4.

The asynchronous three-phase motors to be used for inverter supply are designed and manufactured based on design and manufacturing choices that allow an optimum and reliable operation.
lt has to be considered that generally the inverter supplies the asynchronous motor with a non sinusoidal current having a certain harmonic contents. This is due in particular: to the type of inverter, to the value of the switch frequency, to the length of the supply cables.
Steep voltage fronts to the motor terminals (dv/dt) originated by the short commutation times of the IGBT, generate considerable stresses on the insulating materials.