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8
ELECTRICAL CIRCUITS
 
A. LOG ELECTRICAL CIRCUITS
 
8A1. Types of circuits. (See Figure 8-1.) All electrical circuits that connect to the underwater log are known as Y circuits. All underwater logs, regardless of the manufacturer or type have circuits as follows:

1Y - Speed transmission circuit
2Y - Distance transmission circuit
3Y -Constant frequency supply
2Y100 - Distance transmission to dead reckoning analyzer

8A2. 1Y circuit. (See Figure 8-1.) The speed pointer shaft of the master speed indicator drives the transmitter motor for the 1Y circuit. The movement of the pointer shaft positions the rotor of the transmitter in a corresponding angle, and thus positions the repeater motor which rotates to the same angle. The R1 and R3 internal connections in the speed and distance indicator speed repeater are reversed because the transmitter is actually rotated in a reverse direction to the pointer in the master speed indicator. The transmitter also feeds into the speed corrector in the gyrocompass, and the speed input in the torpedo data computer.

8A3. 2Y circuit. (See Figure 8-1.) The 2Y circuit is the basic circuit in the Pitometer log, as rotary distance is first obtained in the rotary distance transmitter and is later changed to a speed indication in the master speed indicator.

The 2Y circuit supplies 110-115 volts a.c. to the distance transmitting motor in the rotary distance transmitter, and its associated repeating motors, one of which is in the

  master speed indicator, and one in the speed and distance indicator. The circuit from the rotary distance transmitter to the speed and distance indicator passes through the repeater switch on the A.C.O. board. In addition, this circuit supplies power to the pump drive motor (through the transtat, armature rectifiers, and field rectifiers). Connection to the motor circuit is made through two jumpers to terminals 2Y1 and 2YY1.

8A4. 3Y circuit. (See Figure 8-1.) The 115 volt 60 cycle a.c. supply driving the synchronous motor in the master speed indicator is the 3Y circuit. As the entire speed calibration of the log depends on the operation of this motor at constant speed, the 3Y frequency must be held to 60 cycles. To permit the operation of the log if the constant frequency control unit should fail, a selective switch is usually provided that permits the 3Y circuit to operate from the ship's a.c. supply. On some of the latest submarines the ship's a.c. supply is considered accurate enough, and no constant frequency control unit is provided.

8A5. 2Y100 circuit. The right-hand self-synchronous motor in the rotary distance transmitter transmits rotary distance at the rate of 360 revolutions per mile into the 2Y100 circuit. This is connected only to the distance input repeater motor in the dead reckoning analyzer, and not to the tracer of the tracking table. This circuit switch is generally located on the gyro control board, rather than on the I. C. board.

 
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Figure 8-1. Log wiring circuit diagram.
Figure 8-1. Log wiring circuit diagram.
A- SELF-SYNCHRONOUS TRANSMITTER, TYPE B&C
B- SELF-SYNCHRONOUS REPEATER, TYPE M
C- SELF-SYNCHRONOUS REPEATER, TYPE N
D- FOLLOW-UP MOTOR (BARCOL)
E- CONDENSER, .5 MFD.
F- LIMIT SWTICH, NORMALLY CLOSED
G- SLIP RING AND CONTACT ASSEMBLY
J- SYNCHRONOUS MOTOR (BODINE) 1800 R P M
K- STARTING CONDENSER, 2-2.4 MFD.
L- TRANSFORMER, 5 VA.
M- RHEOSTAT, 25-WATT, 30 OHM
N- LAMPS, NAVY TYPE
O- TRANSTAT ASSEMBLY
P- ARMATURE RECTIFIER
Q- FIELD RECTIFIER
R- PUMP DRIVE MOTOR
S- ANTI-HUNTING COIL
T- RESISTOR, 100-OHM
U- RESISTOR, 1000-OHM
V- CONTACTS
 
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