A 460-V, 60-Hz, four-pole induction motor develops its rated torque by drawing 10 A at a power factor of 0.866. The other parameters are as follows:
![1778_89019273-da16-4db7-803a-ad401cde5141.png](https://secure.tutorsglobe.com/CMSImages/1778_89019273-da16-4db7-803a-ad401cde5141.png)
If such a motor is to produce a rated torque at hrequencies below 60 Hz while maintaining a constant air gap flux, calculate and plot the required line-to-line voltage as a function of frequency.