Lambda Electronics 71 User manual

INSTRUCTIONMANUAL
POWERSUPPLY
MODEL____71____ SPEC._______
LAMBDAELECTRONICS CORP.
COLLEGEPOINT 56,N. Y.

INSTRUCTIONMANUAL
FOR
REGULATED POWER SUPPLY
MODEL71
MANUFACTUREDBY
LAMBDAELECTRONICS CORP.
CORONA68, NEWYORK
ISSUE A MODEL NO. 71
1-55-123SERIAL NO.1525

INSTRUCTIONMANUAL
FOR
REGULATED POWER SUPPLY
MODEL71
1. GENERAL DESCRIPTION
1. GENERAL DESCRIPTION.
TheModel 71power supply describedin this manualis
designedfor generalpurpose use inindustry, laboratory,
radiostation andschool to supplypower to electronic and
otherequipment. TheDC output voltages areelectronically
regulated,are practicallyindependent of normal linevoltage
fluctuationsand substantiallyfree from hum and noise. The
high-voltageDC output isconstant (within the specified
limits)from zeroto maximum load andfeatures a continuously-
variable voltage·controlwith anauxiliary vernier-control
for precise voltage adjustment. The DC bias-voltage output
is also continuously adjustable and is closely regulated for
linevoltage variations. The following outputvoltages are
supplied:
Output#1: 0-500VDC, 0-200 MA, regulated.
Output#2: 0-200VDC, 0-50 VDC, bias output. Regulated
for line voltage variation.
Output#3: 6.5VAC, 5A, unregulated.
Output#4: 6.5VAC, 5A, unregulated.
Theeasy-to-read 3-1/2" panelmeters permit monitoring
of output voltage and current. Magnetic circuit-breakers
provideconvenient ACand DC overloadprotection. A time-
delayrelay circuitprotects the tubes duringthe initial
warm-upperiod. Sturdy, insulatedbinding-posts are
providedfor frontpanel connections. A 5651voltage
referencetube insureslong time stability for operation.
Qualitycomponents, conservatlvély rated,guarantee long,
dependabletrouble~free service.
1.

2. ELECTRICAL SPECIFICATIONS:
Input;105-125 VAC,50-60 CPS, 475W (max)
DCOutput No.1; (regulated for lineand load)
Voltage:0-500 VDC (continuouslyvariable)
Current;0-200 MA(over entire voltage range)
Regulation (line); 0.15% or 0.3 volt (whichever is
greater)
Regulation (load); 0.15%or 0.3volt (whicheveris
greater)
InternalImpedence: Lessthan 4 ohms
Ripple and Noise: Less than 5 millivolts rms
Polarity:Either positiveor negative terminal
may be grounded.
DCOutput No.2; (regulated for lineonly)
Voltageranges: Internal Resistance:
a)0-50 VDC(no load) 5,500ohms
b) 0-200 VDC (no load) 25,000 ohms
Currentrange:
Any value of external load impedance may be used
includinga continuouslyapplied low impedance or short-
clrcult.Insignificant interactlonon OutputNo. 1.Short
CircuitCurrent: 9MA (max.)
Regulation (line): Betterthan 0.1%.
Ripple and Noise; Less than 5 millivolts rms.
Polarity:Positive terminalconnected
internallyto negativeterminal of
DCOutput No.1.
ACOutputs (unregulated):
Twooutputs, isolatedand ungrounded. Each is6.5 VAC
at 5A (at 115 VAC input). Allows for drop in connecting
leads.May beconnected in series for 13.0VAC
(nominal)at 5A,or in parallel for 6.5VAC (nom1nal)
at 10A.
2.

AmbientTemperature AndDuty Cycle:
Continuousduty atfull load up to40°C (104°F) ambient.
OverloadProtection:
Externaloverload protectionAC and DCsystems
utilizemagnetic
circuitbreakers. Trip-
Free.Instant manual
reset.Front panel.
InternalFailure ProtectionFuses, access through
rearof cabinet.
InputAnd OutputConnections:
Input8 footheavy duty rubber
coveredline cordwith
integralmolded plug,
rearof cabinet.
OutputSturdy insulated"5-way"
bindingposts, front
panel.
Meters:
OutputVoltage Multi—range 3-1/2"
rectangularvoltmeter
calibrated0-50 VDC,
0-200VDC, 0-500VDC.
OutputCurrent 3-1/2"rectangular
mllliammetercalibrated
0-200MA.
VoltageReference Tube:
A stable 5651 reference tube is used to obtain superior
long—t1me voltage stability.
Time·DelayRelay Circuit:
A 30-sec time delay circuit is provided to allow tube
heatersto cometo proper operating temperature before
high voltage can be applied.
3.

TUBECOMPLEMENT:
TubeType Quantity Function
5R4·GY1 Rectifier
6X4 1 Rectifier
6w6-GT6 ControlTubes
6N0301 TimeDelay Relay
12AX73 VoltageAmplifier
56511 VoltageReference
0A2 1 Voltage Stabilizer
3. MECHANICAL SPECIFICATIONS:
Size and Weight and Finish
Size 13" H x 8-3/4" W x 14-1/2" D
Weight49 lbs.
FinishTwo-tone gray
4.

II.OPERATING INSTRUCTIONS.
MODEL71
1. OPERATINGCONTROLS.
a)The "AC"circuit-breaker is inseries with the AC
lineand controlspower to the supply.When the toggle of
the"AC" breakeris in the"ON" position,the adjacent pilot-
lightindicator marked"AC" is illuminated, theheaters of
allthe tubesin the supplyare energized, anda thirty-second
protectivethermal time·delay relay is setinto operation.
b) The "DC" circuit·breaker contacts are in series
with the plate power relay and controls the application of
platevoltage tothe rectifiers ofthe high—voltage DC and
biassupplies. The“DC“ circuit breaker is interlockedwith
thethermal time-delay relay so that the delay cycle is
completedafter thetube heaters reach operatingtemperature.
Afterthe delaycycle iscompleted the “DC" breaker,when
thrownto the‘DC—ON" position, will apply "DC" power, and
theadjacent pilot—lightindicator will beilluminated. The
"DC"breaker maythen be used in normal switch fashionto
turnDC poweron and off withoutdelay.
c)The "VOLTMETER"toggle~switch connects the
"OUTPUTVOLTAGE" meter to eitherthe "HV" output orthe
"BIAS"output circuitsso that eithervoltage canbe monitored
as desired. The voltmeter circuit is designed so that
switchingfrom biasto high·voltage reading will disturb
neitheroutput voltage.
d) The "HV" control consists of a variable transformer
anda precisionwirewound potentiometer gangedtogether,
andpermits the highvoltage DC output tobe set atany
valuefrom 0to 500 VDC. Thecalibration ofthis control
indicatesthe valueof the DCoutput—voltage andpermits
presettingof the "HV"control beforethe "DC" breakeris
turnedon. Italso provides anindication of the high—voltage
DCoutput whenthe "OUTPUTVOLTAGE" meter is used to monitor
thebias outputvoltage.
e)The "/\HV"control is a wirewoundpotentiometer
permittingvernier controlof the high voltageDC output
for precise voltage adjustment. It has a range of plus or
minus5 voltsand a calibration accuracyof 5%.
f) The "BIAS RANGE" toggle switch provides two ranges
of bias output voltage, 0-50 or 0-200 volts DC.
5.

g) The "BIAS" control is a wirewound potentiometer
whichpermits the biasoutput voltageto be set toany
valuefrom zeroto the maximum outputvoltage ofeither
biasvoltage range.
h) The "OUTPUT VOLTAGE" meter is a 3-1/2 inch panel
instrumentwhich indicateseither the "HV"output or "BIAS"
voltageoutput dependingupon the position ofthe "VOLTMETER"
toggleswitch. Inthe "HV" positionit reads 0-500 VDC full
scale(black numerals).In the "BIAS"position itreads
either0-200 VDC or0-50 VDC (red numerals) dependingupon
theposition of the"BIAS RANGE" switch.
i) The "OUTPUT CURRENT" meter is a 3-1/2 inch panel
instrumentin serieswith the "HV" outputand indicates the
external load current of the high—voltage DC output only.
2. OUTPUT TERMINALS.
a)FRONT PANELTERMINALS:
Theoutput terminalsare sturdy insulated "captive—
head"binding-posts whichcan be used ina number of ways
andare sufficientlysturdy totake a substantial amountof
handlingand abuse. Theywill accept "wrap·around"wire
connections,"alligator clips", bananaplugs, spadelugs,
andwire aslarge as #12 AWG forpermanent feed—through
clamping.The 'HV""BIAS" andeach of the "6.5vAc" output
terminal—pairsare spacedon 3/4 inch centersso that they
willaccept standarddouble bananaplugs.
b) "HV" OUTPUT CONNECTIONS:
Theregulated high-voltageDC output is available
at the front panel terminals marked "HV".
Thepositive connectionis brought out through
thered bindingpost marked "+". The negative connection
is brought out through the black binding post marked "—".
In most applications, it is usual for the negative
terminaletobe atground potential. Insome cases, it may
be desired to place the positive terminal at ground potential.
Stillother applicationsmay require that neitherpositive nor
negativeterminal beat ground potential. In suchcases
whereeither thepositive ornegative terminal is to beat
groundpotential, theappropriate terminal on the panel
should be connected by means of a Jumper wire to the binding e
post,marked "INTGND".
6.

Forminimum outputripple, it is recommended
thateither the positiveor negativehigh voltage DC
outputterminal begrounded.
c)"BIAS° OUTPUTCONNECTIONS:
Theregulated DCbias-output voltage is available
at the front panel terminals marked "BIAS". The positive
"BIAS"connection isinternally tied tothe negative "HV"
connectionand isbrought out through the black binding
postmarked "BIAS+"and "HV-". The negative "BIAS"connection
is brought out through the black binding post marked "BIAS-".
d) AC OUTPUT CONNECTIONS:
TheAC outputconnections marked "6.5VAC 5A"
providetwo independentsources ofunregulated voltage for
vacuum-tubeheater—circuits. Both outputsources are
availableat thefront-panel binding-posts. The AC output
terminals may be connected in series to provide 13.0 VAC
at 5 amperes, or in parallel to provide 6.5 VAC at 10 amperes.
Theschematic diagram onthe panelbelow the AC outputbinding
postsshows theproper connections ofthe terminals for
correct"phasing' ofthese voltages.
_SAFETYNOTICE_
DANGEROUSVOLTAGES EXISTIN THIS EQUIPMENT.
OBSERVETHE USUALSAFETY PRECAUTIONS WHEN OPERATINGOR
SERVICINGTHE EQUIPMENT TOAVOID SEVERE SHOCKOR INJURY.
3. PLACING MODEL71 INTOOPERATION.
a)Both the"AC" and "DC"circuit·breakers snouid be
inthe "OFF"position. The "HV" control andthe "BIAS"
controlshould bein their extremecounter—clockwise positions,
the"/\HV" controlin the centeror "O" position.
b) Plug the power cord into a source of 115 volts AC
50/60cycles.
c)Connect thedesired AC andDC loadsto theoutput
terminals of the supply. Note the schematic diagram on the
frontpanel showingproper phasingof the 6.5 VAC outputs
for series or parallel operation.
d) Throw the "AC" circuit breaker to the "ON" position.
TheAC pilotindicator marked "AC"will be illuminated, and
6.5volts ACwill be present at thefront panelbind1ng·posts.
Thethermal time-delaycircuit will startitS 30·seconddelay-
cycle.
7.

e)After approximately30 seconds, throwthe "DC"
circuit-breakerto the "ON"position. The pilot-light
indicatormarked "DC"will be illuminated,and the internal
plate-power·relaywill close. Ifthe "DC" circuit breaker
is thrown to the "ON" position before the 30 second time
delayhas elapsed,the pilot indicatorwill not light nor
willthe plate-power-relayclose until the time-delaycycle
is complete.
f) After the pilot "DC" indicator 1e illuminated throw
the"VOLTMETER" selectorswitch to the"HV" position. Turn
the"HV" controlclockwise to thedesired DC outputvoltage
as indicated on the "OUTPUT VOLTAGE" voltmeter. The "/\HV"
verniercontrol maybe utilized for precise voltageadjustment.
If an external load is connected to the "HV" output terminals,
theoutput currentwill be indicatedon the "OUTPUT CURRENT"
meter.
g) If use of the "BIAS" output voltage is desired,
throwthe "DC"breaker off, connect the bias-loadto the
"BIAS"terminals, setthe "BIAS RANGE"switch to thebias
voltagerange desired,the "VOLTMETER" selectorswitch
to"BIAS" and the"BIAS" controlto zero. Throw the "DC"
breakeron. Turnthe "BIAS" control clockwiseto therequired
voltageas indicated onthe properred scale ofthe "0UTPUT
VOLTAGE"meter. The"OUTPUT VOLTAGE" metermay be used to
monitorthe biasvoltage, the calibrationon the"HV" control
then serving as an indication of the "HV" output voltage.
h) If it is desired to turn off the DC output only,
usethe "DC"circuit breaker,leaving the "AC" breakerin
the"ON" position.In this manner, the supply willbe in
a standby condition ready for instant use.
CAUTION: Turning the supply on and off rapidly
bymeans ofthe "AC" breaker(with the DCbreaker in the
"ON" position) may seriously damage or impair the life of
thehigh voltagerectifier tube. If less than one minute
elapsesbetween thetime the "AC”breaker is turned off and
turnedon again(the time required for theprotective
thermaltime-delay relayto re—cycle)the "DC" breaker should
be kept in the ”OFF" position for at least 20 seconds after
the"AC" breakeris turned on topermit the rectifier heaters
toreturn toproper operating temperature.
4. OVERLOAD PROTECTION.
a)AC OUTPUTCIRCUITS:
Anoverload orshort circuit of the6.5 VAC 5A
outputcircuits willtrip the "AC" circuitbreaker shutting
off the entire supply. Removing the overeload and turning
8.