Chadburn's Speed Indicator
Chadburn's Speed Indicator was an electrical data system to display a shaft's rotational speed on a dial.
It had three relays, and could indicate whether turbines were going ahead or astern, as well as, in some manner involving a pointer and a counter, the speed. Its short description in the Annual Report of the Torpedo School, 1915 seems to indicate that the electrical relays in turn drove the winding of a clockwork mechanism with a spiral spring. The clockwork action of alternately being wound and released seems to have taken the derivative of the driving shaft, indicating this speed through a pointer on a dial.
- Annual Report of the Torpedo School, 1915. p. 249.
- H.M.S. Vernon. (Jan 1916) Annual Report of the Torpedo School, 1915. C.B. 1166. Copy 1025 at The National Archives. ADM 189/35.