TM 11-5821-284-34
Count
Inputs
Set
Outputs
C
*OCW
**CW
J
J
L
L
S
S
T
T
F
F
A1-3, A2-3
COMMON
COMMON A1-5 A2-6 A1-7 A2-8 A1-9 A2-9 A1-11 A2-11 A1-12 A2-12
Last previous positive pulse
1
0
1
0
0
n
1
1
o
0
1
1
First positive pulse
1
0
0
0
1
1
1
0
0
1
1
0
Second positive pulse
1
0
1
1
0
0
0
1
1
0
0
1
Third positive pulse
1
0
1
0
0
1
1
1
0
0
1
1
Fourth positive pulse
1
0
0
0
1
1
1
0
0
1
1
0
*The following leads are ccw common: A1-1, 2, 8, and A2-1, 2, 7
**The following leads are cw common: A1-6, 13, 14 and A2-5, 13, 14.
Count
Inputs
Set
Outputs
C
*OCW
**CW
J
J
L
L
S
S
T
T
F
F
A1-3, A2-3
COMMON
COMMON A1-5 A2-6 A1-7 A2-8 A1-9 A2-9 A1-11 A2-11 A1-12 A2-12
Last previous positive pulse
O
1
1
0
0
1
1
1
0
0
1
1
First positive pulse
0
1
1
1
0
0
0
1
1
0
0
1
Second positive pulse
0
1
0
0
1
1
1
0
0
1
1
0
Third positive pulse
0
1
1
0
0
1
1
1
0
0
1
1
Fourth positive pulse
0
1
1
1
0
0
0
1
1
0
0
1
Note 1: *The following leads are ccw common: A1-1, 2, 8 and A2-1, 2, 7
Note 2: **The following leads are cw common: A1-6, 13, 14.
Inputs
Outputs
A3A
A3B
A3C
A3A
A3B
A3C
Results
1
2
5
6
8
9
3
7
11
1
1
(1)
0
(1)
0
0
1
1
Energizes blu-orn winding
0
(1)
1
1
(0)
0
1
0
1
Energizes gm-red winding
(1)
0
(0)
0
1
1
1
1
0
Energizes yel-brn winding
Note 1: Logic numbers in parenthesis are not required but are present because of other required Inputs.
Note 2: For cw rotation the windings are energized in the following sequence Blu-orn, yel-brn. and grn-red
Note 3: For cow rotation the windings are energized in the following sequence Blu-orn, gmrn-red, and yel-brn
For a counterclockwise rotation of the dc stepper motor
2-9.
Servo Motor and Motor Control Logic
the windings are energized in the following sequence:
Analysis
blue-orange, green-red, and yellow-brown.
The dc
stepper motor is a variable reluctance step' servo motor
The servo motor control logic consists of 3 basic
and will step 15 degrees each time a different winding is
electronic switches. With a logic "1" input to Q6,
pulsed. .The faster the motor is pulsed, the faster it
transistor Q6 conducts to supply a logic "O" at the base
rotates. The dc stepper motor is mechanically linked to
of Q3. Transistor Q3 biases off. A +28-volt dc signal is
variable capacitor C1.
supplied through CR4 to the blue-orange winding of the
dc stepper servo motor for protection of Q3 from spikes
2-10.
Fine Tune Circuit Analysis
generated by motor windings.
a. With a logic "O" input of Q6, transistor Q6
The fine tune circuit produces a small variable series
biases off supplying a logic "1" to the base of Q3.
inductance to provide incremental tuning of the antenna.
Transistor Q3 conducts to supply a ground potential to
a. With an output from the operational
energize the blue-orange winding of the dc stepper
amplifier AR1, conduction through Q20 changes, pro-
motor.
viding a change In current in L1 and L2. Coils L1 and L2
b. The discussions concerning Q6, Q3, CR4
produce a change in magnetic field proportional to
and the blue-orange winding of the de stepper motor is
operational amplifier input voltage. The change in
also true about Q5, Q2, CR3 and the green-red winding,
magnetic field generated by L1 and L2 changes the
and Q4, Q1, CR2 and the yellow-brown winding.
permeability of the ferrite
c. For a clockwise rotation of the dc stepper
motor the windings are energized in the following
sequence: blue-orange, yellow-brown, and green-red.
2-8
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