BLDC Motor Control: Sine Wave frequency

Hey everyone

I am planning to start with, to control a BLDC motor found in a DVD rom with a 3 sine waves 120 degrees out of phase. Now I have my 3 out of phase signals, but I am curious about something. the frequency of my 3 signals will determine the RPM of the motor, now I dont want to overheat the motor or break it. What is the relationship between Sine wave frequency and a motors RPM?

The equation i found in a document states:

Speed (rpm) = frequency (hertz) x 120 / no. of poles

thanks in advance XD