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| Number | Title | Issue Date |
| 4378587 | Frequency converter apparatus Disclosed is a frequency converter system for altering the frequency of a-c power supplied from a distribution network to a load, the system including a pair of mechanically coupled rotating alternating current machines, the alteration of the rate and dir... | 03/29/1983 |
| 4135118 | System for determining the relative angular positions of the rotors of two synchronously driven synchronous motors A system for determining the relative angular positions of two magnetic-p rotors of respective synchronously driven (same speed) synchronous motors operated from a common frequency generator applying the driving frequency to the motors. Each rotor is pro... | 01/16/1979 |
