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Servo Unit

Technical Information

Catalogue No: C0665
Category: Flight Control
Object Type: Actuator
Object Name: Servo Unit
Part No: CSM 329 Iss 4
Serial No: 90245
Manufacturer: OTM Servo Mechanism
Division: Unknown
Platform(s): Phoenix UAV
Year of Manufacture: circa 1990
Dimensions: Width (mm): 92
Height (mm): 43
Depth (mm): 124
Weight (g): 343
Location: Rack RAA02 [Main Store]

O.T.M. Servo Mechanism Ltd.
The Causeway, Egham, Surrey.
Tel. 0784-33155/6
Telex 934524
Type Ref. CSM 329 Iss. 4
Serial No 90245
Flight Refuelling Ref. No:
ENG/ND/BSG/R163 Iss. 3


In control engineering a servomechanism, sometimes shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. It usually includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect. The term correctly applies only to systems where the feedback or error-correction signals help control mechanical position, speed or other parameters.
This type of servo provides position control. They operate on the principle of negative feedback, where the control input is compared to the actual position of the mechanical system as measured by some type of transducer at the output. Any difference between the actual and wanted values (an "error signal") is amplified (and converted) and used to drive the system in the direction necessary to reduce or eliminate the error. This servo unit would have driven one of the flying control surfaces and it is electrically driven.

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