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11
SELSYN-OPERATED SYSTEMS
 
A. MOTOR ORDER TELEGRAPH SYSTEM
 
11A1. Description. The motor order telegraph system consists of 2 separate electrical circuits. The starboard circuit is designated 1MB and the port circuit, 2MB. Electrically both circuits are identical. The system is operated on 115-volt, 60-cycle, single-phase, alternating current. Each circuit receives its supply from the a.c. bus of the I.C. switchboard through fused switches.

The purpose of the motor order telegraph system is to transmit electrically any desired orders for the direction and speed of the propellers from the transmitting stations located in the conning tower and control room to the maneuvering room and to repeat those orders back to the transmitting station from the maneuvering room.

The circuits are controlled through rotary switches on the action cutout switchboard. One switch selects the conning tower or the control room as the transmitting station for both 1MB and 2MB circuits. Two more switches select either the conning tower, control room, or both, as the receiving station for the repeat back orders from the maneuvering room. One of these 2 switches is for the 1 MB, the other for the 2 MB indicators.

The conning tower and control room units consist essentially of a type "A" transmitter and pointer, a type "M" indicator and pointer, 2 sets of contacts for bell-ringing circuits, and necessary operating gears. The assembly is mounted in a case.

The transmitter is operated by a knob type handle fastened to a shaft on the front cover of the instrument. This shaft is connected to the transmitter rotor by means of a positive engaging clutch. A star wheel mounted on the transmitter shaft holds the transmitter in the desired position by means of a spring loaded main bell contact actuating lever. This lever also operates the contacts for the bell signal at the indicator

  station. The bell signal rings whenever the transmitter is being moved from one position to another. Auxiliary contacts for the bell signal are operated by a push button on the cover of the instrument. They are connected in parallel with the contacts operated by the star wheel. The auxiliary bell-ringing circuit is energized at any time the push button is operated. The indicator pointer is connected directly to the rotor of the indicator through an extension shaft.

The maneuvering room instruments are similar except for an additional mechanism consisting of a cam mounted on the transmitter shaft which operates a contact for wrong direction warning. These contacts are connected with contacts on the reverser levers of the main control cubicle. If the reverser levers are moved in a direction opposite to that indicated by the transmitter pointers of the maneuvering room instruments, a visual and audible signal informs the operator of the error.

11A2. Operation. In order to energize the system, the- IMB and 2MB circuit switches on the I.C. switchboard must be turned to the ON position. On the action cutout switchboard, turn the 1MB-2MB transmitter selector switch to the station that is to control transmission. This switch is marked CONNING TOWER, OFF, and CONTROL ROOM. Next, turn the 1MB and the 2MB indicator selector switches to those stations that are to receive a repeat indication of the transmitter order. These switches are marked CONNING TOWER, OFF, CONTROL ROOM, and CONTROL ROOM AND CONNING TOWER.

NOTE. Before transferring control from one station to another, be sure that the station you are transferring to has its transmitters set on the same order, otherwise, the maneuvering room will receive whatever order is indicated at the new transmitting station.

 
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Figure 11-1. Schematic diagram of motor order telegraph system.
Figure 11-1. Schematic diagram of motor order telegraph system.
 
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Figure 11-2. Schematic diagram of motor order telegraph, two units.
Figure 11-2. Schematic diagram of motor order telegraph, two units.
Figure 11-3. Motor order telegraph transmitter
indicator unit, maneuvering room.
Figure 11-3. Motor order telegraph transmitter indicator unit, maneuvering room.
  Figure 11-4. Side view of motor order telegraph transmitter indicator unit, maneuvering room.
Figure 11-4. Side view of motor order telegraph transmitter indicator unit, maneuvering room.
 
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Figure 11-5. Elementary wiring diagram of motor order telegraph transmitter indicator, conning tower and control room units.
Figure 11-5. Elementary wiring diagram of motor order telegraph transmitter indicator, conning tower and control room units.
 
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Figure 11-6. Elementary wiring diagram of motor order telegraph transmitter indicator, maneuvering room unit.
Figure 11-6. Elementary wiring diagram of motor order telegraph transmitter indicator, maneuvering room unit.
 
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Figure 11-7. Schematic diagram of motor order telegraph transmitter and indicator.
Figure 11-7. Schematic diagram of motor order telegraph transmitter and indicator.
11A3. Maintenance. The bearings, gears, cams, and other moving parts should be inspected periodically to see that they are in proper alignment and working freely. A drop or two of fine-grade mineral oil may be applied to the bearings if necessary. Contacts should be checked for signs of pitting and wear. Slightly worn or pitted contacts may be dressed with very fine sandpaper and crocus cloth.

The instrument cases are sealed. If a

  pressure test is to be conducted in a compartment in which an instrument is located, make certain that the plug located on the case is opened. With the plug opened, the air pressure in the compartment necessary to conduct the test, and the pressure in the case will be equalized, thus avoiding possible damage to the instrument.

The transmitters and indicators should be maintained as outlined in the maintenance instructions for selsyn units (Section 10B2).

 
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Figure 11-8. Schematic diagram of rudder angle indicator system.
Figure 11-8. Schematic diagram of rudder angle indicator system.
 
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B. RUDDER ANGLE INDICATOR SYSTEM
 
11B1. Description. The rudder angle indicator system is designated as circuit N. It is operated on 115-volt, 60-cycle, single-phase, alternating current and receives its supply from the a.c. bus of the I.C. switchboard through a fused switch.

The purpose of the system is to transmit

  electrically the angular position of the rudder to various stations in the control room, conning tower, and bridge.

The circuit is controlled through 2 rotary contact switches on the action cutout switchboard. One switch energizes the conning tower and bridge indicators, the other switch energizes

Figure 11-9. Rudder angle indicator and case.
Figure 11-9. Rudder angle indicator and case.
Figure 11-10. Rudder angle transmitter.
Figure 11-10. Rudder angle transmitter.
  Figure 11-11. Rear view of rudder angle transmitter.
Figure 11-11. Rear view of rudder angle transmitter.
 
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the indicators located in the control room.

The transmitting instrument consists essentially of a type "A" transmitter mounted in a case. Any movement of the rudder is transmitted mechanically through a linkage or gear arrangement that causes the rotor of the type "A"

  those stations at which an indication of the rudder angle is desired. One of these switches controls the bridge and conning tower indicators. It is marked BRIDGE, OFF, CONNING TOWER, and BRIDGE AND CONNING TOWER. The other switch controls the control
Figure 11-12. Cross-sectional view of rudder angle transmitter.
Figure 11-12. Cross-sectional view of rudder angle transmitter.
transmitter to rotate in a corresponding direction.

The indicating instrument consists essentially of a type "M" indicator, a pointer, and a dial mounted in a case. The indicator pointer is secured to the indicator rotor shaft.

11B2. Operation. In order to energize the system, the circuit N switch on the I.C. switchboard must be turned to the ON position. On the action cutout switchboard, the circuit N indicator selector switches should be turned to

  room indicators and is marked STEERING STATION, OFF, DIVING STATION, and DIVING AND STEERING STATION.

11B3. Maintenance. The operating mechanism between the transmitter instrument and the rudder should be examined periodically to make certain that it is operating freely but without any backlash. For maintenance of the selsyn units, the procedure outlined in Section 10B2 should be followed.

 
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Figure 11-13. Wiring diagram of rudder angle Indicator.
Figure 11-13. Wiring diagram of rudder angle Indicator.
 
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Figure 11-14. Rudder angle Indicator, showing pressure-proof construction for bridge installation.
Figure 11-14. Rudder angle Indicator, showing pressure-proof construction for bridge installation.
 
C. BOW AND STERN PLANE ANGLE INDICATING SYSTEMS
 
11C1. Description. The bow plane angle indicating system is designated as circuit NB. The stern plane angle indicating system is designated as circuit NS. Both of the systems are operated on 115-volt, 60-cycle, single-phase, alternating current, and receive their supply from the a.c. bus of the I.C. switchboard individually, through fused switches.

The purpose of the systems is to transmit electrically the angular position of the bow and stern diving planes to the diving station in the control room. The instruments and the mechanical arrangements connected to them are similar to those employed in the rudder angle indicator system.

Auxiliary circuits XNB (bow plane) and

  XNS (stern plane) are provided for use in the event of failure of the selsyn-operated systems (see Section 11C4).

11C2. Operation. The bow plane angle indicator system is energized by turning the switch labeled for this system on the I.C. switchboard to the ON position. The stern plane angle indicating system switch is also on the I.C. switchboard; turning it to the ON position energizes the system.

11C3. Maintenance. The mechanical operating mechanism between the transmitters and the diving planes should be examined periodically to see that proper alignment and free movement without backlash are maintained. See Section 10B2 for maintenance of selsyn units.

 
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Figure 11-15. Schematic diagram of bow and stern plane angle indicating systems.
Figure 11-15. Schematic diagram of bow and stern plane angle indicating systems.
 
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Figure 11-16. Wiring diagram of bow and stern plane angle indicating systems.
Figure 11-16. Wiring diagram of bow and stern plane angle indicating systems.
 
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Figure 11-17. Bow and stern plane angle indicators installed at diving station.
Figure 11-17. Bow and stern plane angle indicators installed at diving station.
11C4. Auxiliary bow and stern plane angle indicating systems. The auxiliary bow and stern plane angle indicating systems are provided for use in the event of failure of the regular selsyn-operated systems (Section 11C1) or of the I.C. power.

The circuits are designated XNB (bow plane) and XNS (stern plane) and consist of mechanical transmitters connected to the diving plane mechanisms, a group of dry cell batteries,

  and lamp type indicators located in the control room.

Motion of the diving planes moves the mechanical transmitters across a number of contacts, thus closing the circuits to the lamps mounted on a panel in the control room. The dry cells are connected to produce an output of 6 volts for each of the circuits which are energized by means of a snap switch in the control room.

 
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Figure 11-18. Schematic diagram of auxiliary haw and stern plane angle indicating systems.
Figure 11-18. Schematic diagram of auxiliary haw and stern plane angle indicating systems.
 
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Figure 11-19. Auxiliary bow plane angle indicator at diving station.
Figure 11-19. Auxiliary bow plane angle indicator at diving station.

11C5. Bow plane rigging electrical indicator system. The anchor windlass, bow capstan and bow plane rigging gear is electrically operated through hydraulic gearing and has an electric indicating system. The indicating system takes power at 120 volts d.c. through a snap switch and fuses on the I.C. switchboard in the control room, and shows indications at the diving station.

A contact maker on the rig windlass clutch in the forward torpedo room lights a

  CLUTCH IN RIG indicator at the diving station and closes a circuit to another contact maker on the windlass control valve in the forward torpedo room. This contact maker is closed when the control valve is in neutral.

When both these contact makers are closed, the WINDLASS VALVE IN NEUTRAL indicator at the diving station is lighted and the circuit is completed to an interlock on the tilting gear which is closed only when the planes are at zero tilt.

When all three of these contact makers are closed, indicating that the clutch in the rig windlass control valve is in neutral and that the planes are at zero tilt, a PLANES AT ZERO indicator at the diving station is lighted. The circuit is then completed to a RIGGING LEVER RELEASE push button, also located at the diving station. Pressing this push button releases a solenoid latch on the rigging lever, allowing the planes to be rigged either in or out.

A traveling nut type limit switch on the rigging gear in the forward torpedo room closes a circuit at either end of its travel through the rig-windlass clutch and windlass control valve contact makers to PLANES OUT or PLANES IN indicators at the diving station.

An intermediate contact maker operated from the hydraulic interlock shaft of the rigging mechanism makes a series of intermittent contacts while the planes are rigging in or out and flashes an indicating light at the diving station to indicate that the planes are moving in or out. The circuit for this indicating light goes through the traveling nut limit switch so that the circuit is opened when the planes are full IN or full OUT.

 
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Figure 11-20. Schematic diagram of bow plane rigging indicator circuit.
Figure 11-20. Schematic diagram of bow plane rigging indicator circuit.
 
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Figure 11-21. Bow plane rigging indicator, bow plane rigging and windlass clutch indicator, bow and stern plane motor ON lights and controllers at diving station.
Figure 11-21. Bow plane rigging indicator, bow plane rigging and windlass clutch indicator, bow and stern plane motor ON lights and controllers at diving station.
 
D. ENGINE GOVERNOR CONTROL SYSTEM
 
11D1. Description. a. General. The engine governor control system is the system through which the maneuvering room controls the speed of the engines. On vessels having single unit propulsion control cubicles, the system consists of 4 selsyn transmitters mounted in the governor control cabinet in the maneuvering room. Each transmitter is connected to a selsyn indicator (motor) mounted on the mechanical governor control of each engine. The indicators are geared to the rack shafts of the engine governors. When a change in the speed setting is made at the transmitters, the indicators move the rack shafts. They in turn transmit motion to mechanical linkage to establish an engine speed in accordance with the transmitter setting.

The system is designated as circuit EG and on earlier vessels is operated on 115-volt, 60-cycle, single-phase, alternating current supplied from the a.c. bus of the I.C. switchboard in the

  control room. On SS 313 and subsequent vessels, the governor control transmitters and receivers are of the direct current type described below and receive their power from the lighting system.

b. Engine governor control, direct current. The direct current position transmitters and receivers used in this type of governor control (Figure 11-23), while in external appearance similar to the a.c. types, are in reality entirely different both in principle of operation and in construction. The transmitter unit consists essentially of a continuous, cylindrical wire wound resistor unit. Two taps, diametrically opposite, are connected to slip rings which are fed through brushes from the 115-volt lighting circuit. Equally spaced around the fixed part of the transmitter shell are 4 more brushes which make contact directly on the wires of the resistor. The transmitter shaft turns the resistor unit mounted

 
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Figure 11-22. Schematic diagram of engine governor control system.
Figure 11-22. Schematic diagram of engine governor control system.
 
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on the shaft. A friction device is also included to prevent too rapid turning of the transmitter. Unlike the a.c. selsyns, none of the effort used to turn the receiver is supplied by the transmitter. It is all supplied electrically.

The receiver consists of a stator, wound as a 2-phase motor as shown in Figure 11-23, and

  transmitter dial should be matched with the tachometer. This is necessary because the large gear ratio between the dial and the transmitter makes it possible for the transmitter to be synchronized with the receiver at several different positions.

A mechanical clutching device is provided

Figure 11-23. Elementary wiring diagram of d.c. governor control, Allis-Chalmers pointer transmitter.
Figure 11-23. Elementary wiring diagram of d.c. governor control, Allis-Chalmers pointer transmitter.
a magnetized solid iron rotor with 2 poles. As the transmitter resistor is rotated, the voltage across each of the 2 windings varies and reverses its direction. The permanent magnet rotor follows until its poles are lined up with the magnetic field which is the resultant of the 2 windings.

11D2. Operation. Each of the governor control units is provided with an OFF-ON switch mounted at the transmitter station. Governor control from the maneuvering room may be cut in or out as desired. Before an engine is started, care should be taken to see that its individual governor control switch is in the OFF position and kept there until the engine room signals READY. Before turning the switch to ON, the

  by which any single governor control transmitter may be operated individually; or any number of them may be clutched together for common operation through a master control handle.

NOTE. On vessels having split type propulsion control cubicles, the governor control transmitters are also split into 2 cabinets which are somewhat different in operation from those described above. Each cabinet has 3 transmitters and 2 selector switches. The arrangement is such that the third transmitter on either side may be connected to the receiver of either of the engines associated with the other side. It is thus possible to operate any 3 engines in unison. However, it is not possible to operate 4 engines

 
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Figure 11-24. Engine governor control panel on main
control cubicle.
Figure 11-24. Engine governor control panel on main control cubicle.

in unison. This can be done only with the single unit type governor control.

11D3. Maintenance. Maintenance of a.c. selsyn units is described in Section 10B2. For d.c. selsyns, the general comments of Section 10B2 apply, but the symptoms and remedies do not. If the rotor of the receiver sticks, no damage results. If the receiver rotates in the wrong direction, one pair of leads is reversed (A1 + A2) or (B1 + B2). If it does not rotate in either direction, and is not stuck, the A and B leads

  Figure 11-25. Engine governor control unit at engine.
Figure 11-25. Engine governor control unit at engine.

are interconnected; for example A1 to B1, and A2 to B2.

11D4. Tachometer system. The tachometer system consists of a magnetic generator on each engine and an indicator electrically connected to each of them. The system, by means of a flexible shaft connected to the driving gear of the magneto, also drives a mechanical tachometer located on the engine gage board.

The magneto is mechanically driven by the engine and generates a voltage as a function of its speed. This voltage is impressed on the indicator, which is basically a voltmeter with a scale calibrated in rpm. The 4 indicators are mounted on the engine governor control panel in the maneuvering room.

 
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Figure 11-26. Fairbanks-Morse tachometer installation.
Figure 11-26. Fairbanks-Morse tachometer installation.
Figure 11-27. Electric Tachometer engine unit and indicator.
Figure 11-27. Electric Tachometer engine unit and indicator.
  Figure 11-28. Weston electric tachometer magneto, engine unit.
Figure 11-28. Weston electric tachometer magneto, engine unit.
 
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