Synchro Connections of a Synchro Amplifier

A synchro amplifier cycle of operation takes place

S2 to terminal block terminal B2

as follows:

S3 to terminal block terminal B3

1. A change occurs in the remotely transmitted

When the shaft of the synchro is to be driven clockwise

synchro data.

for an increasing reading, the connections to the

2. The signal received by the synchro control

terminal bus should be as follows:

transformers in the mechanical unit is, as an error volt-

R1 to terminal block terminal B

age, amplified and used to operate the servomotor. The

R2 to terminal block terminal BB

servomotor, through gearing, turns the synchro control

transformer rotors until the error voltages are zero (or,

S3 to terminal block terminal B1

in the low-speed unit, matched to the stickoff voltage),

S2 to terminal block terminal B2

thereby stopping the turning or follow-up action.

S1 to terminal block terminal B3

3. Simultaneous with step 2, the servomotor also

drives the rotors of the output synchros into alignment

For a synchro control transformer, these con- nections

with the new input signal.

will apply to the stator, but the rotor connections go to

the input of the servo amplifier.

Synchro Connections of a Synchro Amplifier

Cutover Circuit

The conventional connection is for counterclock-

wise rotation for increasing reading-an increasing read-

The purpose of the cutover circuit is to auto-

matically select the error voltage from either the high

ing is when the numbers associated with the action being

measured are increasing. The five wires of a synchro

(36 speed) or low (1 or 2 speed) synchro control

system are numbered in such a way that the shaft of a

transformer and feed it to the servo-amplifier input

normal synchro will turn counterclockwise. When an

terminals. The low-speed control transformer is

increasing reading is sent over the wires provided, the

connected when the error is large (more than 2 1/20),

and the high-speed control transformer is connected

synchro is connected as follows:

when the error is small (less than 2 1/20).

R1 to terminal block terminal B

The cutover circuit (fig. 2-12) consists of six diodes

R2 to terminal block terminal BB

(CR12A through CR17) and three resistors (R12, R13,

S1 to terminal block terminal B1

and R14). The circuit operates on the principle that

Figure 2-12.--Cutover circuit.

2-11