| 摘要 |
The drive for magnetic films of different format and/or for different running speeds and/or power frequencies comprises a multi-pole synchronous motor (3) connected to a converter (4) for converting pulses of variable frequency to a.c. for controlling the motor, and a sprocket (2) for conveying the film (1) coupled directly to the motor shaft. The converter is supplied by a frequency converter (6) of which the variable conversion factor is selected according to a formula involving the no. of perforations in the film per picture, the no. of poles of the motor, the ratio of pulse frequency to the frequency of the a.c. which supplies the motor, the picture frequency, the power frequency, and the no. of teeth on the sprocket. |
