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).
Investigation into the operation of a Midgley cutout and controller for dynamo control.
| Identifier | ExFiles\Box 35\3\ scan 088 | |
| Date | 21th May 1926 | |
| AC. 74. 21st May, 1926. MIDGLEY CUTOUT AND CONTROLLER. This apparatus was received from the makers with a view to our investigating the scheme of dynamo control it employs. The cutout and controller are mounted side by side on a common base and under one cover. Each consists of a single bobbin magnetic circuit wound with shunt and series coils and fitted with armatures operating contacts. In each case the contacts are duplicated. The cutout operates on the usual lines while the controller has contacts which are normally closed and which have a resistance connected across them. They are connected in the field circuit of the dynamo and when the controller operates, due to the rise of voltage on the shunt coil, the resistance is inserted in the dynamo field circuit. There is a large "overlap" in the controller operation so that with no load on the dynamo-battery combination, once the points have opened, they will not close again until the dynamo drops below charging speed. Lamp or other loads, however, are fed through the series coil of the controller in such a direction as to oppose the shunt coil, so that when large enough, they cause the controller to fall back, closing the contacts and allowing the dynamo to deliver at full rate. Contd. | ||