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4. Related Devices
Synchros play a very important role in the operation of Navy equipment. Synchros are found in just about every weapon system, communication system, underwater detection system, and navigation system used in the Navy. The importance of synchros is sometimes taken lightly because of their low failure rate. However, the technician who understands the theory of operation and the alignment procedures for
synchros is well ahead of the problem when a malfunction does occur. The term “synchro” is an abbreviation of the word “synchronous.” It is the name given to a variety of rotary, electromechanical, position-sensing devices.
Servo mechanisms, also called SERVO SYSTEMS or SERVOS for short, have countless applications in the operation of electrical and electronic equipment. In working with radar and antennas, directors, computing devices, ship’s communications, aircraft control, and many other equipments, it is
often necessary to operate a mechanical load that is remote from its source of control. To obtain smooth, continuous, and accurate operation, these loads are normally best controlled by synchros. As you already know, the big problem here is that synchros are not powerful enough to do any great amount of work. This is where servos come into use. A servo system uses a weak control signal to move large loads to a desired position with great accuracy. The key words in this definition are move and great accuracy. Servos may be found in such varied applications as moving the rudder and elevators of a model airplane in radio-controlled flight, to controlling the diving planes and rudders of nuclear submarines.
Servos are powerful. They can move heavy loads and be remotely controlled with great precision by synchro devices. They take many forms. Servo systems are either electromechanical, electrohydraulic, hydraulic, or pneumatic. Whatever the form, a relatively weak signal that represents a desired movement of the load is generated, controlled, amplified, and fed to a servo motor that does the work of moving the heavy load.
The word gyroscope was first coined by a French scientist, Leon Foucault, in 1852. It is derived from the Greek words “gyro,” meaning revolution, and “skopien,” meaning to view. The gyroscope, commonly called a GYRO, has existed since the first electron was sent spinning on its axis. Electrons spin and show all the characteristics of a gyro; so does the Earth, which spins about its polar axis at over 1000 miles per hour at the Equator. The Earth’s rotation about its axis provides the stabilizing effect that keeps the North Pole pointed within one degree of Polaris (the North Star). Any rapidly spinning object—a top, a wheel, an airplane propeller, or a spinning projectile—is fundamentally a gyroscope. Strictly speaking, however, a gyroscope is a mechanical device containing a spinning mass that is universally mounted; that is, mounted so it can assume any position in space.
The engine order telegraph, steering telegraph, rudder-angle indicator, and similar positionindicating systems used on naval ships are usually simple synchro systems. Some ships, however, use IC synchros to transfer such information. These units operate on the same general principle as the synchros we discussed in chapter 1. The interior communication synchro (IC synchro) is gradually being phased out and replaced by standard synchros when replacement is required. However, you will still find some IC synchros in use today. For that reason, you will find some background information on their purpose and theory to be beneficial. We will present these synchros in very basic form in the following paragraphs. Because of their construction, IC synchros are sometimes called reversed synchros. The primary winding, consisting of two series-connected coils, is mounted physically on the stator. The secondary, consisting of three Y-connected coils, is mounted physically on the rotor.
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