From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification sheet for a Ferranti synchronous electric stop clock.
| Identifier | ExFiles\Box 151\2\ scan0339 | |
| Date | 28th May 1937 guessed | |
| F E R R A N T I. SYNCHRONOUS ELECTRIC STOP CLOCK. Our new self-starting synchronous motor has been embodied for driving purposes in an electrical stop clock. The movement is contained in a 6" dial black and nickel finished metal case, and has a main pointer moving smoothly over the dial at the rate of 1 revolution in 10 seconds, also a subsidiary pointer reading up to 10 minutes. Thus, reading to half a division, operation up to 10 minutes duration can be timed to 1/20th second. When required the movement can be geared to give other pointer speeds down to 1 rev. per minute for the large pointer. An extra charge is made for this. Both pointers can be reset to zero instantaneously by depressing the knob which projects from the side of the case and engages with two heart-shaped cams fitted internally. Starting and stopping errors are avoided as the motor runs continuously, the clock being set in motion by a clutch operated electrically by external means. The speed of the rotor is 200 r.p.m. with a torque of approximately 20 grm.cms. Two pairs of terminals are provided, one pair for the motor 200-250 volts, 50 cycles, and the other for the clutch, the coil of which can be arranged for any convenient voltage, AC or DC. The clock should be used preferably with its dial in the horizontal position. Dimensions Base 8" diam. Height 4" Weight 6 1/2 lbs (approx). | ||