Temperature measuring system for rotating machines

Claim 1

Apparatus for a contact free transmission of signals between a stationary portion and a movable portion of a machine comprising: inductive coupling means including a stationary coupling member arranged on said stationary portion of said machine and a movable coupling member arranged on said movable portion of said machine, said movable coupling member including two connection terminals, and said stationary coupling member including at least a first terminal; an oscillator for generating an AC auxiliary voltage signal with a defined zero passage, the output of said oscillator being connected to said first terminal for transmission of said auxiliary voltage to said movable portion of said machine; a pulse detector connected to said first terminal; a pulse generating means connected to said two connection terminals; a transducer arranged in said movable portion of the machine for providing a variable measurable quantity to be transmitted to said stationary portion of said machine and said transducer being connected to said pulse generating means; said pulse generating means being arranged to generate short pulses having respective phase positions in relation to respective zero passages of the auxiliary voltage signal dependent upon the level of the measurable quantity; and, said pulse detector being supplied with said auxiliary voltage signal and pulses from said pulse generating means through said inductive coupling, said pulse detector being arranged to determine the phase position of such pulses which is indicative of the level of the measurable quantity.