Figure 2-13.--Computer system, functional diagram.

corresponding voltage that is proportional to the speed

CROSSWIND AND HEADWIND

of the wind. This windspeed voltage is then applied to

COMPUTER

the wind direction circuit where the crosswind and

An elaborate development of a transmission system

headwind components are developed.

is the crosswind and headwind computer system, de-

The windspeed synchro signal input is applied to the

signed for use aboard CVAs. Although this system is

not at present intended for use aboard other vessels, its

stator of the control transformer in the windsped

design should be interesting to you as an application of

circuit. The output of the control transformer is an error

voltage representing the difference between the

synchro and servomechanism basics.

electrical angle of the synchro signal and the mechanical

The crosswind and headwind computer receives

angle of the stator in the control transformer. This error

relative wind direction and speed information from a

voltage feeds to the servo amplifier through a

wind direction and speed indicator system, as shown in

transformer, not shown in the functional diagram. The

figure 2-13. The output from the computer is in the form

purpose of the transformer is to compensate for the

of variable voltages. These voltages represent the

phase shift caused by the inductance of the windings of

factors of windspeed from dead ahead, across the beam,

the control transformer rotor. The signal fed to the

and parallel to and across the angled deck of the carrier.

amplifier is either 0 or 180 from correspondence with

These voltages are applied to indicators that provide

the line voltage. The amplifier is a push-pull type, and

direct reading of crosswind and headwind speeds in

applies an output voltage to the second coil of the

knots. The crosswind and headwind computer assembly

servomotor, thereby controlling the direction and speed

is shown in figure 2-14, and a functional diagram of the

of the motor.

computer assembly is shown in figure 2-13. In fig-

ure 2-13, the heavy lines represent signal flow and the

The servomotor drives a gear train that positions the

dashed lines represent mechanical linkages that make

rotor of the control transformer, driving it until it

the system self-synchronous.

corresponds with the input signal. The gear train also

positions the arm of the precision potentiometer that

WINDSPEED CIRCUIT

regulates the dc power supply input. The position of the

arm of the potentiometer determines the amount of

voltage applied to the sine-cosine potentiometer in the

The windspeed circuit takes the synchro signal

wind direction circuit. This voltage is proportional to the

from the windspeed transmitter and converts it to a

Figure 2-13.--Computer system, functional diagram.

2-14