Induction generator

I have an induction generator on the same shaft with induction motor. Both machines are same (have same nameplate: $U=400\,V$, $f=50\,Hz$, $n=1435\, rpm$, $P=9.3\,kW$, $\cos(\phi) = 0.90$, $I = 17.05\,A$). The motor is supplied via three phase inverter and the generator is connected to three phase AC/DC converter. The induction motor is supplied by 50 Hz three phase voltage and has four poles ($p_p=2$). I expect that the mechanical speed of the motor and also the generator is same $n_m < 1500\,rpm$ (but close to 1500 rpm). The corresponding mechanical frequency is $f_m < 1500/60 = 25\,Hz$). If I want the generator to produce electrical power I need to achieve negative slip ($s = \frac{(f_s-f_m)}{f_s}$) in the generator. So I have to supply its stator with electrical frequency $f_s < f_m$ so for example 20 Hz would be sufficient. Is it correct?