All induction motor have speed proportional with frequency. When reduce frequency, alson need to reduce voltage to keep same flux.
This is automaticaly made by inverter in various mode (depend of control method); when reduce voltage by k, torque is reduced by k^2, so torque may
became very low at small speed. May try to use 3-phase inverter for tests but check voltages and manual inverter also to find if there are some restriction /
protections to avoid single phase load. There are another single phase motor used in home-appliances, but with brushes; this motor is so called universal
motor and in fact is a DC motor with series excitation coil; this construction allow it to accept DC and AC voltage; for this motor type can't change speed by
changing frequency, as it is a DC motor (collector - brushes is an "mechanical rectifier"); is not recomanded to use this motor without load because speed
up very high and risk to destroy itself and lead to injuries.