Synchro: Difference between revisions

A '''synchro''' (also known as '''selsyn''' and by other brand names) is, in effect, a [[transformer]] whose primary-to-secondary coupling may be varied by physically changing the relative orientation of the two windings. Synchros are often used for measuring the angle of a rotating machine such as an [[antenna (electronics)|antenna]] platform or transmitting rotation. In its general physical construction, it is much like an electric motor. The primary winding of the transformer, fixed to the [[Rotor (electric)|rotor]], is excited by an [[alternating current]], which by [[electromagnetic induction]], causes voltages to appear between the Y-connected secondary windings fixed at 120 degrees to each other on the [[stator]]. The voltages are measured and used to determine the angle of the rotor relative to the stator.

A synchro will fall into one of eight functional categories. They are as follows:<ref>"MIL-HDBK-225A, ''Synchros. Description and Operation''", 25 March 1991, Department of the Navy, Washington D.C., Table 1, Page 82.]</ref>

:: Input: rotor positioned mechanically or manually by the information to be transmitted.

:: Output: electrical output from stator identifying the rotor position supplied to a torque receiver, torque differential transmitter or a torque differential receiver.

:: Input: same as TX.

:: Output: electrical output same as TX but supplied to a control transformer or control differential transmitter.

: :Input: TX output applied to stator; rotor positioned according to amount data from TX that must be modified.

: :Output: electrical output from rotor (representing an angle equal to the algebraic sum or difference of rotor position angle and angular data from TX) supplied to torque receivers, another TDX, or a torque differential receiver.

: :Input: same as TDX but data supplied by CX.

: :Output: same as TDX but supplied to only a control transformer or another CDX.

: :Input: Electrical angle position data from TX or TDX supplied to stator.

: :Output: Rotor assumes position determined by electrical input supplied.

; Torque Differentialdifferential Receiverreceiver (TDR)

: :Input: electrical data supplied from two TX's, two TDX's or from one TX and one TDX (one connected to the rotor and one connected to the stator).

: :Output: rotor assumes position equal to the algebraic sum or difference of two angular inputs.

: :Input: electrical data from CX or CDX applied to stator. Rotor positioned mechanically or manually.

: :Output: electrical output from rotor (proportional to sine of the difference between rotor angular position and electrical input angle).

: This synchro was designed as a torque receiver, but may be used as either a transmitter or receiver.

: :Input: depending on the application, same as TX.

: :Output: depending on the application, same as TX or TR.