Features and Applications VHSVF-seriesVVVF adjustable speed vertical hollow-shaft three-phase
induction motors, designed with computer aided technology .In order
to apply the supply, the stator, rotor slot and distribution or
stator winding have been given special consideration to get a
suitable inductance value for restraining and reducing adverse
effects caused by time harmonic wave and a series of space harmonic
waves produced by the former. Allowance for electromagnetic load
has been taken into account to ensure the overload capability at
high frequency and constant torque output at low frequency. The impact of high carrier frequency of the frequency converter has
been pondered in designing the insulation structure of the motors.
Especially for the turn-to-turn insulation, in order to make it
capable of being subjected to the severe ordeal resulting from the
steep shock voltage applied repeatedly in the coil turns by the
high voltage rise, special measures have been adopted to reinforce
it. The tested values of interturn voltage endurance of the motors
are much higher than the specified figures for AC motors in
standard. Speed can be adjusted in a wide range motors can achieve the speed
regulation with constant torque at 10-50Hz and with constant output
at 50-70Hz. The forced ventilation by and independent axial blower is adopted,
with which the motors can be guaranteed to operate for constant
torque over a long period of time at the low speed(with the
temperature rise not exceeding a prescribed limit.)