HP Lab Series User Manual

5-29
A mercury-wetted
relay,
as
connected
in
the
load
switching
circuit
of
Figure
5~~
should
be
used
for
loading
and
unloading
the
supply.
When
this
load
switch
is
connected
to a
60Hz
ac
input,
the
mercury-wetted
relay
will
open
and
close
60
times
per
second.
Adjustment
of
the
2
SK
control
permits
adjustment
of
the
duty cycle
of
the
load
current
switching
and
reduction
in
jitteroJthe
osdlfoscope
display.
. .
POWER
SUPPLY
UNDER
TEST
+
CONTACT PROTECTION
NETWORK
0.1.1
snsw
400V
(NOTE 3)
Ry
OSCILLOSCOPE·
@
130C
NOTES:
.
I.THIS
DRAWING SHOWS
A
1
SUGGESTED
METHOD
OF
...._
____
"°""'_
f
BUILDING
A
LOAD
SWITCH.
f
HOWEVER,
OTHER
METHODS
COULD
BE
USED,
SUCH
AS
A
I
TRANSISTOR SWITCHING
f
NETWORK. MAXIMUM
LOAD
RATINGS
OF
LOAD
SWITCH
I
ARE;
5
AMPS.
soov.
250W
I
(NOT
2500Wl
NOTE2f 2.USE MERCURY RELAY1
I
CLARE
TYPE
HGP
1002
OR
W.E.
TYPE
2768,
I
REPETITIVE
f
3.USE WIRE
WOUND.
RESISTOR
J.:.O.!°
~~C.!:
~~~
_J
Figure
5-6.
Transient
Recovery
Time,
Test
Setup
5•3
0
The
maximum
load
ratings.listed
in
Fig\lre
S-6
must
be
observed
in
order
to
preserve
the
mercury-
wetted
relay
contacts.
Switching
of
larger
load
currents
can
be
accomplished
with
merciiry
pool·
relays;
with
this
technique
fast
rise
times
can
still
be
obtained,
but
the
iarge
inertia
of
mercury
pool
relays
limits
the
maximum
repetition
rate
of
load
switching
and
makes
the
clear
display
of
the
transient
recovery
characteristic
on
an
oscill~s~pe
more
difficult.
5-31
To
check
the
transient
recovery
time,
pro-
ceed
as
foilows:
a.
Connect
test
setup
showp
in
Figure
5-6.
b.
Turn
CURRENT
ctintrols
fblly
clockwise.
c.
TUrn
on
supply
and
adjusf
voltage
con-
trols
until front
panel
ammeter
indicates
exactly
5 Amperes.
d.
Close
the
line
switch
on
the
repetitive
load
switch
setup.
e.
Set
the
oscilloscope
for
internal
sync
and
lock
on
either
the
positive
or
negatiw
load
transient
spike.
5-6
f.
Set
the
vertical
input
of
the
oscilloscope
for
ac
coupling
so
that
small
de
level
changes
in
the
output
voltage
of
the
power
supply
will
not.
cause
the
display
to
shift.
•
g.
Adjust
the
sync
controls
separately
for
the
positive
and
negative
going
transients
so
that
not
only
the
recovery
waveshape
but
also
as
must
as
possible
of
the
rise
time
of
.the
transient
is
display-
ed.
h.
Starting
from
the
major
graticule
division
representative
of
time
zero,
count
to
the
right
5011-
sec
and
vertically
lOmV.
Recovery
should
be
within
these
tolerances
as
illustrated
in
Figure
5-7.
IOMV
T
IOMV
ENOM_....._...._~~~~~~
UNL.OADING
TRANSIENT
v
50a
SECONDS
~ADING
TRANSl'ENT
Figure
S-7.
Transient
Recovery Time, Waveforms
5-32
OUTPUT
IMPEDANCE
5-33
To
check
the
output
impedance,
proceed
·as
follows:
a.
Connect
test
setup
shown
in
Figure
5-8~
VOLTMETER
VOLTMETER
llp4()38
llP4038
INDICAll:S
Eo
INDICATES
Ela
.
I)
~
>O
)
0
0
POWER
SUPPLY
OSCIU.ATOR
UNDER
TEST
bp200
CD
)
....
t-="I+
G
0 '
-
r-9
U>
I
IK
500MFD
I
.
-11+
"¥111
IOOOHM
Figure
5-8.
Output
Impedance,
Test
Setup
•
•

HP Lab Series Specifications

General

Brand	HP
Model	Lab Series
Category	Power Supply
Language	English