Tektronix FG 5010 User Manual

Theory of
Operation
- FG
5010
the output filter for use in the Output Amplifier . Zener diode
VR1521
and
R1532 provide a
nominal 5 V
positive supply
for U1521 . The negative supply for U1521 comes directly
from the -26 V input . The amplifier is controlled at the in
verting input by the voltage across divider string R1441 ,
R1440 , and R1442 , which connects from +12 to 12 V.
Amplifier R1521 keeps the wiper of R1440 at ground by
varying the 12 V output . Thus , the 12 V supply tracks
the +12 V supply . Adjustment of the 12 V is by R1440 .
Transistor
Q1430
protects the
negative
supply in the
event that the two supplies move too far apart . For exam
ple , if at
turn - on the
negative fails to
operate
, the
positive
supply voltage at R1441 can pull pin 2 of U1521 up only
0.7 V above
ground before
Q1430
conducts
,
clamping the
positive regulator at approximately +1.4 V.
In normal operation , changes from the supplies are
amplified by U1521 and coupled to the base of driver
Q1610
.
Zener diode
VR1520 prevents the base of
Q1610
from
exceeding -18 V ,
limiting
the
output
voltage
in
case of
amplifier
failure
.
From
the
emitter
of
Q1610
,
any
change is
coupled to the base of the pass transistor on the Power
Module , to increase or decrease the current to the load , as
required . In the collector circuit of Q1610 , resistor LR1614
protects Q1610 from overload if the FG 5010 is installed
into an energized Power Module by limiting the current
through the transistor . The voltage across current - sense re
sistor
R1520
is
applied
to
the
base
-
emitter
junction
of
cur
rent - limit
transistor
Q1611 ,
which
limits the
regulator
output
at 700 mA ; into a short circuit , the current limit is reduced to
400 mA or
less . The
12 V
regulated output is
filtered by
C1520 , then split and filtered through L1110 and C1000 on
one leg , and
L1112 and C1010 on
the other , then
applied to
the
output
pins .
16 V
POWER
SUPPLY
Introduction
This
section
furnishes six
different voltages : the +
and
-26 V from the Power Module , the + and -35 V , and the
+ and -26 V.
+26
and
-26 V
Supplies
The +26
V from
the
Power
Module
comes
through fuse
F821 , then passes through a filtering circuit , from where it is
fed to the Offset Generator .
The 26 V , also from the Power Module , follows the
same kind of path to the Negative Offset Generator .
Both supplies are used in the generation of the other four
voltages
.
4-46
+35
V
and
-35 V
Supplies
The floating 26 V ac from the power module is applied
across CR1801 , which is connected to stack on the +26 V
supply . The voltage from CR1801 is filtered across C1801 ,
then held to a nominal +35 V by R1702 - VR1701 . The out
put
voltage is
furnished to the
Positive
Offset
Generator de
picted on
Diagram
26 .
The -35 V supply is essentially the same as the +35 V
supply . Current for this supply is also taken from a 25 V ac
winding . The supply is stacked on the -25 V supply , and
the
resultant
nominal -35 V is
used to
operate the
Negative
Offset
Generator
depicted on
Diagram 26 .
+ 16
V
Supply
This
supply consists of
U1711
,
the
regulator
stage ,
pass
transistor Q1701 , and related components . Reference for
the regulator is by means of divider string R1815 - R1814
R1812 , connected across the +12 V supply . Thus , +6 V is
furnished at
U1711 pin 5 as a
reference
voltage
.
Current limiting for the supply is provided by circuits in
ternal to U1711 , using R1711 as the limit sense resistor .
Diode
CR1711 prevents the
output from going
negative
in
the event of severe current limit conditions . Jumper P1711
is provided as a troubleshooting aid .
-
16
V
Supply
This supply
consists
of
regulator
U1731 ,
current sense
transistor Q1841 , a pass transistor on the Power Module ,
and related components . Operation of the 16 V regulator
is
similar to
that
of
the
+16
V
regulator .
The
regulator is
referenced
to
the 12 V
supply at pin 5 .
Since U1731 is a positive regulator , Q1841 is added to en
sure that the current sense operates properly . Otherwise ,
this
supply
operates
the
same as the
+16 V
supply
.
4 MAGLATCH STROBE GENERATOR
Maglatch
Strobe
Circuit
This
circuit produces the drive
signal
for
the
magnetic
latch relays in
the FG 5010.
The circuit can
drive up to five
relays at once , although there are no more than four ener
gized at once . Two signals are produced by the circuit : the
MAGLATCH
STROBE
signal ,
which is the
signal
that
ener
gizes the relays , and the END OF STROBE signal , which
informs
the
CPU the
strobe
signal
is
ended
.
The Maglatch Strobe Circuit consists of the Control Log
ic , U1234C and U1234D ; Strobe Generator U1232A ; and
U
U
U
U
U
U
U
U
U
U
U

Tektronix FG 5010 Specifications

General

Brand	Tektronix
Model	FG 5010
Category	Portable Generator
Language	English