(Modified problem 3-11 in Chapman) In later years, motors improved and could be run directly from a 50 Hz power supply. As a result, 16.67 Hz power systems shrank and disappeared. However, there were many perfectly good working 16.67 Hz motors in factories around the country that owners were not ready to discard. To keep them running, some users created their own 16.67 Hz power in the plant using motor-generator sets. A motor-generator set consists of two machines connected on a common shaft, one acting as a motor and the other acting as a generator. If the two machines have different numbers of poles but exactly the same shaft speed, then the electrical frequency of the two machines will be different due to relationship fse = nsm⋅P/120. What combination of poles on the two machines could convert 50 Hz power to 16.67 Hz power?