HP HVB Series User manual

DC POWER SUPPLY
HVB SERIES, MODEL 6515A
SERIAL NUMBER PREFIX 6C
Printed: February,
1 967
@ Stock Number: 06515-90001

TABLE OF CONTENTS
Section
I GENERAL INFORMATION
1-1 Description
1-4 Overload Protection
1-7 Cooling
1-9 Output Terminals
1-1 1 Specifications
1-13 Options
1-1 5 Accessories
1-17 Instrument Identification
1-20 Ordering Additional Manuals
I1 INSTALLATION
2-1 Initial Inspection
2-3 Mechanical Check
2-5 Electrical Check
2-7 Installation Data
2-9 Location
2-11 Rack Mounting
2-1 5 Input Power Requirements
2-17 Power Cable
2-20 Repackging for Shipment
III
0 PERATING INSTRUCTIONS
3-1 Controls and Indicators
3-3 Operation
3-5 Constant Voltage Operation
3-7 Current Limit Provisions
3-10 Operation of Supply Beyond
Rated Output
3-12 Connecting Load
3-1 6 Output Capacitance
3-1 8 Reverse Current Loading
3-20 Reverse Voltage Loading
IV PRINCIPLES OF OPERATION
4-1 Overall Block Discussion
4-6 Detailed Circuit Analysis
4-12 Main DC Supply
Page No.
1-1
1-1
1-1
1-1
1-1
1-1
1-1
1-1
1-2
1-2
Section Page No.
I
V PRINCIPLES OF OPERATION
4-14 Series Regulator 4-2
4-1 8 Constant Voltage Input Circuit 4-2
4-21 Driver Circuit 4-2
4-2 3 Reference Regulator
V
MA1 NTENANCE 5-1
5-1 Introduction 5-1
5-3 Measurement Techniques 5-1
5-6 Test Equipment Required 5-1
5-8 Performance Test 5-3
5-11 Rated Output, Meter, and Output
Controls Accuracy 5-3
5-1 4 Load Regulation 5-3
5-1
6 Line Regulation 5-3
5-18 Ripple and Noise 5-3
5-20 Transient Recovery Time 5-4
5-22 Output Impedance 5-4
5-24 Temperature Coefficient 5-5
5-26 Output Stability 5-5
5-28 Current Limit 5-5
5-30 Troubleshooting 5-5
5-32 Trouble Analysis 5-5
5-37 Repair and Replacement 5-8
5-39 Adjustment and Calibration 5-8
5-41 Meter Zero 5-10
5-43 Meter Accuracy Adjustment 5-10
5-45 Output Voltage (Programming
Current) Adjustment 5-10
5-47 Output Current Limit Adjustment 5-11
V I RE PLACEABLE PARTS
6-1 Introduction
6-4 Ordering Information
Reference Designators
Abbreviations
Manufacturers
6-8 Code List of Manufacturers 6-2
Parts List Table 6-5

ELECTRONIC INSTRUMENTATION SALES AND SERVICE
UNITED STATES, CANADA, CENTRAL AND SOUTH AMERICA
UNITED STATES
ALABAMA
P.O. Box 4207
2003 Byrd Spring Road S.W.
Huntsville 35802
TWX: 510-579-2204
Tel: [phone]
ARIZONA
3009 North Scottsdale Road
Scottsdale 85251
Tel: [phone]
TWX: 910-950-1282
232 South Tucson Boulevard
Tucson 85716
Tel: [phone]
TWX: 910-952-1162
CALIFORNIA
3939 Lankershim Boulevard
North Hollywood 91604
Tel: [phone]
TWX: 910-499-2170
1101 Embarcadero Road
-.
Palo to 94303
Tel: [phone]
TWX: 910-373-1280
2591 Carlsbad Avenue
Sacramento 95821
Tel: [phone]
TWX: 910-367-2092
1055 Shafter Street
San Diego 92106
Tel: [phone]
TWX: 910-335-2000
COLORADO
7965 East Prentice
Englewood 80110
~eb(303) 771-3455
TWX: 910-935-0705
CONNECTICUT
508 Tolland Street
East Hartford 06108
Tel: [phone]
TWX 710-425-3416
111 East Avenue
Norwalk 06851
Tel: [phone]
TWX: 710-468-3750
DELAWARE
3941 Kennett Pike
Wilmington 19807
Tel: [phone]
TWX: 510-666-2214
CANADA
BRITISH COLUMBIA
Hewlett-Packard (Canada) Ltd.
2184 West Broadway
Vancouver
Tel: [phone]
TWX: 610-922-5050
CENTRAL AND
ARGENTINA
Mauricio A. Suirez
Telecomunicaciones
Carlos Calvo 224
Buenos Aires
Tel: 30-6312, 34-9087
BRAZIL
Ciental, ImportacZo e
Comhrcio Ltda.
Rua Cleto Campelo, 44
- 5" andar
Recife
Ciental, lmportac$o e
Com6rcio Ltda.
Avenida 13 de Maio, 13-22" andar
Rio de Janeiro, G.B.
Ciental, ImportacBo e
comircid Ltda.
Rua Des. Eliseu Guilherme, 62
Qo Paula 8
FLORIDA
Suite 106
9999 N.E. 2nd Avenue
Miami Shores 33138
Tel: [phone]
TWX: 810-848-7262
P.O. BOX20007
Herndon Station 32814
621 Commonwealth Avenue
Orlando
Tel: [phone]
TWX: 810-850-0113
P.O. BOX8128
Madeira Beach 33708
410 150th Avenue
St. Petersburg
Tel: [phone]
TWX: 810-863-0366
GEORGIA
3110 Maple Drive N.E.
Atlanta 30305
Tel: [phone]
TWX: 810-751-3283
ILLINOIS
5500 Howard Street
Skokie 60076
Tel: [phone]
TWX: 910-223-3613
INDIANA
4002 Meadows Drive
Indianapolis46205
Tel: [phone]
TWX:'~~O-341-3263
LOUISIANA
P.O. Box 856
1942 Williams Boulevard
Kenner 70062
Tel: [phone]
TWX: 810-955-5524
MARYLAND
6707 Whitestone Road
Baltimore 21207
Tel: [phone]
TWX: 710-862-0850
P.D. Box 727
Twinbrook Station 20851
12303 Twinbrook Parkway
Rockville
Tel: [phone]
TWX: 710-828-9684
ONTARIO
Hewlett-Packard (Canada) Ltd.
880 Lady Ellen Place
Ottawa 3
Tel: [phone]
TWX: 610-562-1952
SOUTH AMERIC
CHILE
Hector Calcagni
Casilla 13942
Santiago
Tel: 490.505, 393.119
COSTA RlCA
Lic. Alfredo Gallegos Gurdien
Apartado 3243
San Jose
Tel: 21-86-13
EL SALVADOR
Electr6nica
Apartado Postal 1589
San Salvador
Tel: 4683
MASSACHUSETTS
Middlesex Turnpike
Burlington 01803
Tel: [phone]
TWX: 710-332-0382
MICHIGAN
24315 Northwestern Highway
Southfield 48076
Tel: [phone]
TWX: 810-232-1532
MINNESOTA
2459 University Avenue
St. Paul 55114
Tel: [phone]
TWX: 910-563-3734
MISSOURI
9208 W~ominrrPlace
Kansasiity64114
Tel: [phone]
TWX: 910-771-2087
2812 South Brentwood Blvd.
St. Louis 63144
Tel: [phone]
TWX: 910-760-1670
NEW JERSEY
Crystal Brook Prof. Bldg.
Route 35
Eatontown
Tel: [phone]
391 Grand Avenue
Englewood 07631
Tel: [phone]
TWX: 710-991-9707
NEW MEXICO
P.O. BOX8366
Station C 87108
6501 Lomas Boulevard
N.E.
Albuquerque
Tel: [phone]
TWX: 910-989-1665
156 Wyatt Drive
Las Cruces 88001
Tel: [phone]
TWX: 910-983-0550
Hewlett-Packard (Canada) Ltd.
1415 Lawrence Avenue West
Toronto
Tel: [phone]
TWX: 610-492-2382
:A
GUATEMALA
Oiander Associates Latin America
Apartado 1226
7a. Calie, 0-22, Zona 1
Guatemala City
Tel: 22812
MEXICO
Hewiett-Packard Mexicana.
S.A. de C.V.
Eugenia 408, Dept.
1
Mexico 12, D.F.
NICARAGUA
Roberto Teren G.
Edificio Teren
Apartado Postal 689
Managua
Tel: 3451, 3452
NEW YORK
1219 Campville Road
Endicott 13760
Tel: [phone]
TWX: 510-252-0890
236 East
75th Street
New York 10021
Tel: [phone]
TWX: 710-581-4376
82 Washington Street
Poughkeepsie 12601
Tel: [phone]
TWX: 510-248-0012
39 Saginaw Drive
Rochester 14623
Tel: [phone]
TWX: 510-253-5981
1025 Northern Boulevard
Roslyn, Long Island 11576
Tel: [phone]
TWX: 510-223-0811
5858 East Molloy Road
Syracuse 13211
Tel: [phone]
TWX: 710-541-0482
NORTH CAROLINA
P.O. Box 5187
1923 North Main Street
High Point 27262
Tel: [phone]
TWX: 510-926-1516
OHIO
5579 Pearl Road
Cleveland 44129
Tel: [phone]
TWX: 810-421-8500
1250 West Dorothy Lane
Dayton 45409
Tel: [phone]
TWX: 810-459-1925
OREGON
2737 S.W. Corbett Avenue
Portland 97201
Tel: [phone]
PENNSYLVANIA
Park Place Office Building
Camp Hill
Tel: [phone]
QUEBEC
Hewlett-Packard (Canada) Ltd.
275 Hvmus Boulevard
Pointe Claire
Tel: [phone]
TWX: 610-422-3022
Telex: 01-2819
PANAMA
Electr6nico Balboa, S.A.
P.O. Box 4929
Panama City
Tel: 3-0833
PERU
Fernando Ezeta B.
Av. Petit Thouars 4719
Casilla 3061
Lima
Tel: 50346
PUERTO RlCO
San Juan Electronics, Inc.
Ponce de Ledn No. 150, Stop 3
Pta. de Tierra Sta.
San Juan
Tei: [phone]
Monroe Complex
Moss Side Boulevard
Monroeville 15146
Tel: [phone]
TWX: 710-797-3650
144 Elizabeth Street
West Conshohocken 19428
Tel: [phone]
TWX: 510-660-8715
TEXAS
P.O. BOX7166
3605 lnwood Road
Dallas 75209
Tel: [phone]
TWX: 910-861-4081
P.O. BOX22813
4242 Richmond Avenue
Houston 77027
Tel: [phone]
TWX: 910-881-2645
GOVERNMENT CONTRACT OFFICE
225 Billy Mitchell Road
San Antonio 78226
Tel: [phone]
TWX: 910-871-1170
UTAH
2890 South Main Street
Salt Lake Citv 84115
Tel: [phone]
TWX: 910-925-5681
VIRGINIA
P.O. BOX6514
2111 Spencer Road
Richmond 23230
Tel: [phone]
TWX: 710-956-0157
WASHINGTON
11656 N.E. Eighth Street
Bellevue 98004
Tel: [phone]
TWX: 910-443-2303
FOR AREAS NOT
LISTED, CONTACT:
Hewlett-Packard
1501 Page Mill Road
Palo Alto. California 94304
Tel: [phone]
TWX: 910-373-1267
Telex: 34-8461
FOR AREAS NOT
LISTED, CONTACT:
Hewlett-Packard Inter-Americas
1501 Page Mill Road
Palo Alto, CBlifornia 94304
Tel: [phone]
TWX: 910-373-1267
Telex: 034-8461
Cable: HEWPACK Palo Alto
VENEZUELA
Citec, C.A.
Edif. Arisan-Of. #4
Avda. Francisco de Miranda
Apartado del Este 10934Chacaito
Caracas
Tel: 71.88.05
FOR AREAS NOT
LISTED, CONTACT:
Hewlett-Packard Inter-Americas
1501 Page Mill Road
Palo Alto, California 94304
Tel: [phone]
TWX: 910-373-1267
Telex: 034-8461
Cable: HEWPACK Palo Alto
Tel: 70-2318

c
TABLE OF CONTENTS (CONTINUED)
LIST OF TABLES
Table
1 Page No.
1-1 Specifications 1-3
5-1 ~ebtEquipment 5-1
5-2 Reference, Bias, and Filtered DC
Voltage Troubleshooting
I
5-6
5-3 Low Output Voltage Troubleshooting
5-7
Table Page No
5-4 High Output Voltage Troubleshooting
5-8
5-5 Selected Semiconductor Characteristics 5-8
5-6 Checks and Adjustments After Replace-
ment of Semiconductor Devices 5-1C
LIST OF ILLUSTRATIONS
Figure
I Page No. Figure Page No
1-1 ?C Power Supply i v 5-2 Line and Load Regulation, Test Setup 5-3
2-1 yack Mounting, Two Units 2-1 5-3 Transient Recovery Time, Test Setup 5-4
2-2 qack Mounting, One Unit 2-2 5-4 Transient Recovery Time, Waveforms 5-4
3-1 Front Panel Controls and Indicators 3-1 5-5 Output Impedance, Test Setup 5-4
3-2 gutputCurrentLimitingCharacteristics 3-2 5-6 Servicing Printed Wiring Boards 5-9
4-1 Qverall Block Diagram 4-1
5-1 Differential Voltmeter Substitute
Test Setup

Figure 1-1.
DC Power Supply, Model 651 5A

1-2
ducto
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SUPP~
adjus
1-3
a swi
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necte
outpu
the
s~
1-5
contr~
terna:
The s
stant
versa
prese
put c
1-6
voltas
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curre
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SUPP~
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1-8
quire
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1-10
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SECTION I
GENERAL INFORMATION
ESCRIPTION
:ode1 6515A (Figure 1-1) is an all semicon-
ligh voltage supply suitable for either
r relay rack operation. It is a compact,
gulated Constant Voltage
/ Current Limited
:hat will furnish 1600V at 5mA or can be
j throughout the output voltage range.
nis supply
is series regulated and utilizes
ned output piggyback technique; four
:onnected low voltage supplies are con-
~iathe VOLTAGE RANGE switch to the
(+)
erminal. A fifth supply is connected via
esregulator to the
(-) output terminal.
VERLOAD PROTECTION
le VOLTAGE RANGE switch and VERNIER
select the constant voltage level. An in-
otentiometer selects the current limit level.
ply will automatically crossover from con-
)Itage to current limit operation and vice
the output current or voltage exceeds these
evels. Detailed characteristics of the out-
ent limiting are given in paragraph 3-7.
he power supply is protected from reverse
(positivevoltage applied to negative ter-
)y an internal protection diode that shunts
across the output terminals when this con-
xists, clamping the reverse voltage. Pro-
from reverse current (current forced into the
upply in the direction opposite to the output
must be provided
by preloading the power
(Paragraph 3-1 8). The power supply cannot
:everse current without damage.
OOLING
onvection cooling is used. No fan is re-
The power supply has no moving parts (ex-
. meter movement).
lUTPUT TERMINALS
lutput power is available via two UG-931/U
:ors at the rear of the power supply. Mating
:ors (UG-932/U) are supplied with the unit.
The output terminals are isolated from the chassis
and either the positive or the negative terminal may
be connected to the chassis by shorting the center
pin and case of the applicable UG-931/~connector,
or by grounding a wire from the connector to the
chassis. The power supply is insulated to permit
operation up to 1,000 vdc off ground,
i. e. the max-
imum potential between either output terminal and
ground shall not exceed
2.6 KV DC.
1-11 SPECIFICATIONS
1-12 Detailed specifications for the power supply
are given in Table
1-1.
1-1 3, OPTIONS
1-14 Options are factory modifications of a
standard instrument that are requested by the
customer. The following options are available for
the instrument covered by this manual. Where
necessary, detailed option information is included
throughout the manual.
Option No. Description
Three Digit Graduated Decadial
Voltage Control: Includes a cali-
brated 10-turn control replacing the
10-turn vernier to provide resettabil-
ity within 0. 1%.
1-1
5 ACCESSORIES
1-16 The accessories listed in the following chart
may be ordered with the power supply or separately
from your local Hewlett-Packard sales office.
(Refer to list atrear of manual for addresses.)
Part No. Description
8" Black Handle that can be at-
tached to side of supply.
14513A Rack Kit for mounting one
3 l/2"
- high supply. (Refer to
Section I1 for details.
)
Rack Kit for mounting two
3 1/2"
- high supplies. (Refer to
Section I1 for details.
)

1-1 7 INSTRUMENT IDENTIFICATION
1-1 8 Hewlett-Packard power supplies are identi
fied by a three-part aerial number tag. The first
part is the power supply model number. The
sec
ond part is the serial number prefix, which con-
sists of a number-letter combination that denote:
the
date of a significant design change. The
number designates the year, and the letter A
through
L designates the month, 'January through
December respectively. The third part
is the
power supply serial number.
1-19 If the serial number prefix on your power
supply does not agree with the prefix on the title
page of this manual, change sheets are included
to update the manual. Where applicable, back-
dating information
is given in an appendix atthe
rear of the manual.
1-20 ORDERING ADDITIONAL MANUALS
1-21 One manual is shipped with each power sup-
ply. Additional manuals may be purchased from
your local Hewlett-Packard field office (see list
at rear of this manual for addresses). Specify the
model number, serial number prefix, and
@ stock
number provided on the title page.

Table 1-1. Specifications
OUTPUT: OVERLOAD PROTECTION:
0-1600 VDC, 0-5 milliamps. A current limit circuit protects the supply
for all overload conditions, including a short
INPUT: circuit applied directly across the output termi-
105-125 VAC, single phase, 60It0.3
Hz nals.
(cps)
, 162 ma, 19watts max. CONTROLS
:
LOAD REGULATION: Sixteen position rotary switch adjusts the
Less than 0. 01% or 16millivolts (which- output voltage in 100-volt steps; a 10-turn
ever is greater) output voltage change for full vernier permits continuous adjustment with a
load change-. 100 MV resolution over any 100-volt span.
I
LINE REGULATION:
Less than 0. 01% or 16 millivolts (which-
ever is greater) output voltage change for a line
input change from 105 to 125volts.
RIPPLE AND NOISE:
Less than 2 mv RMS. Less than 5 mv
peak-to-peak.
TEMPERATURE COEFFICIENT:
Output voltage change per degree centigrade
is less than 0.02% plus 2 millivolts.
STABILITY:
The total drift for 8 hours (after 30 minutes
warmup) at a constant ambient
is less than 0.05%
plus
5 millivolts.
TEMPERATURE RATING:
Operating: Oto 500C
Storage: -20 to +850C
OUTPUT IMPEDANCE:
Less than 32 ohms from DC to 30
Hz (cps)
Less than 8 ohms from 30
Hz to 100 kHz
Less than 2 ohms from 100 kHz to 1 MHz
METER:
A 0-1800 volts mounted on the front panel.
OUTPUT TERMINALS
:
A positive and a negative output terminal
(type UG931 connectors) are included on the front
panel. Two mating connectors (UG932) are
in-
cluded with each unit. Either side may be ground-
ed by shorting one of the UG932 connectors, or
the supply may be operated floating up to 1000
volts off ground.
RFI: Conducted and radiated leakage limits are
below those specified in MIL-1-6181D.
SIZE: 3 l/2"
(89 mm) Hx8 1/2" (216 mm) Wx
11 13/16" (300 mm)D.
WEIGHT:
12 pounds (5.44 kg) net, 15 pounds
(6. 8
kg) shipping.
FINISH:
Light gray front panel with dark gray case.
POWER CORD:
A 3-wire 5-foot (1. 52 m) power cord is
provided with each unit.
TRANSIENT RECOVERY TIME:
Less than 100 microseconds
is required for
output voltage recovery to within 0. 01% or 16 mv
of the nominal output voltage following a full
load change in output current. The nominal out-
put voltage
is defined as the mean between the
no load and full load voltage.

SECTION I1
INSTALLATION
2-1 INITJALINSPECTION
2-2 Before shipment, this instrument was in-
spected and found to be free of mechanical and
electrical defects. As soon asthe instrument is
unpacked, inspect for any damage that may have
occurred in transit. Save all packing materials
until the inspection is completed. If damage is
found, proceed as described in the Claim for
Damage inShipment section of the warranty page
at the rear of this manual.
2 -3 MECHANICAL CHECK
2-4 This check should confirm that there are no
broken knobs or connectors, that the cabinet and
panel surfaces are free of dents and scratches,
and that the meter is not scratched or cracked.
2-5 ELECTRICAL CHECK
2-6 The instrument should be checked against its
electrical specifications. Section
V includes an
"in-cabinet" performance check to verify proper
instrument operation.
2 -7 INSTALLATION DATA
2-8 The instrument is shipped ready for bench
operation. It is necessary only to connect the in-
strument to a source of power and it is ready for
operation.
2-9 LOCATION
2-10 This instrument is air cooled. Sufficient
space should be allotted so that a free flow of
cooling air can reach the sides and rear of the in-
strument when
it is in operation. It should be used
in an area where the ambient temperature does not
exceed 50°C.
2-11 RACK MOUNTING
2-12 This instrument may be rack mounted in a
standard 19 inch rack panel either alongside a
similar unit or
by itself. Figures 2-1 and 2-2
show how both types of installations are accom-
plished.
Figure
2-1. Rack Mounting, Two Units
2-1

Figure 2-2. Rack Mounting, One Unit
2-13
ITO mount two units side-by-side, proceed
as follows:
la. Remove the four screws from the front
panels of both units.
Ib. Slide rack mounting ears between the
front panel and case of each unit.
Ic. Slide combining ship between the front
panels and cases of the two units.
Id. After fastening rear portions of units to-
gether using the bolt, nut, and spacer, replace
panel screws.
2-1
5 INPUT POWER REQUIREMENTS
2-14 To mount a single unit in the rack panel,
proceed as follows:
I a. Bolt rack mounting ears, combining
strip?, and angle brackets to each side of center
spacisng panels. Angle brackets are placed behind
combining straps as shown in Figure 2-2.
unit.
panel
2
-1 7 POWER CABLE
b.
Remove four screws from front panel of
C.
Slide combining strips between front
and case of unit.
d. Bolt angle brackets to front sides of case
2-16 This power supply is operated from
a nominal
11 5 volt 60 cycle power source. The input power re-
I
quired when operated from a 11 5 volt 60 cycle
I
2-18 To protect operating personnel, the National
Electrical Manufacturers Association (NEMA) rec-
ommends that the instrument panel and cabinet
be
grounded. This instrument is equipped with a
three conductor power cable. The third conductor
is the ground conductor and when the cable is
plugged into an appropriate receptacle, the instru-
ment is grounded. The offset pin on the power
cable three-prong connector is the ground connec-
tion.
and replace front panel screws.
I
power
2-19 To preserve the protection feature when op-
erating the instrument from
a two-contact outlet,
use a three-prong to two-prong adapter and con-
nect the green lead on the adapter to ground.
source at full load is
40 watts and 1 ampere.
2-20 REPACKAGING FOR SHIPMENT
2-21 To insure safe shipment of the instrument, it
is recommended that the package designed for the
instrument be used. The original packaging mate-
rial is reusable. If it is not available, contact
your local Hewlett-Packard field office to obtain
the materials. This office will also furnish the
address of the nearest service office to which the
instrument can be shipped. Be sure to attach a
tag to the instrument which specifies the owner,
model number, full serial number, and service
re-
quired, or a brief description of the trouble.

SECTION I11
0 PERATING INSTRUCTIONS
3-1 CONTROLS AND INDICATORS means). The operator can ground either output
terminal or operate the power supply up to 1,000
3-2 The controls and indicators are illustrated in Vdc off ground (floating). It is not recommended
Figure 3-1. that the power supply be floated above 300 vrms at
low audio frequencies (less than 500
Hz).
TURN-ON SEQUENCE
1. PUSH ON/OFF BUTTON AND ENSURE THAT LIGHT GOES
ON.
2. SET VOLTAGE RANGE SWITCH TO THE NEAREST POSI-
TION THAT IS LESS THAN THE DESIRED OUTPUT
VOLTAGE.
3. TURN THE VERNIER CONTROL UNTIL THE METER INDI-
CATES EXACTLY THE DESIRED OUTPUT VOLTAGE.
4. ATTACH A MULTIMETER TO THE OUTPUT AND SET THE
VOLTAGE RANGE SWITCH TO AT LEAST 200 VOLTS.
CHECK THAT THE CURRENT INDICATION ON THE
MULTIMETER DOES NOT EXCEED
7. 5 mA.
5. REMOVE METER AND CONNECT LOAD TO OUTPUT
TERMINALS.
Figure 3-1. Front Panel Controls and Indicators
3-3 OPERATION
3-4
The power supply can be operated as a sin-
gle unit (normal operation), in parallel, or in
.
series. No provisions for remote programming or
remote sensing have been made due to their limited
use and insulation problems at 1,000 Vdc. For
safety, ensure that the power supply chassis is
grounded (either through power cord or by other
WARNING
Serious injury to personnel
can occur if the power supply
chassis is ungrounded. The
warranty
is void if the chassis
is ungrounded during operation
3-5 CONSTANT VOLTAGE
0 PERATION
3-6 To select a constant voltage output turn on
the supply, and with no load connected, set the
VOLTAGE RANGE switch to the nearest position
that is less than the desired output voltage. Now
turn the VERNIER control until the meter indicates
exactly the desired output voltage.
3-7 CURRENT LIMIT PROVISIONS
3-8 The current limiting feature is designed
mainly to protect the supply, not the load. It is
internally adjusted so that the short-circuit output
current will not exceed approximately 7.
5 mA in the
lower voltage ranges, 0 to 300 Volts. The range of
this adjustment
is 5 to 10 mA.
However, in the
higher voltage ranges the limit is substantially
higher and no provisions are included for adjusting
the level. The current limit for each voltage range
is as follows:
VOLTAGE RANGE
Switch Setting
0
- 300V
400
- 700V
800
- 1100
1200
- 1500
Output
Current Limit

OUTPUT CURRENT - MILLIAMPERES
3-9
Figure 3-2. Output Current Limiting Characteristics
Figure 3-2 illustrates the output current
chara~teristicsof ,thesupply from no load to full
3-1
0 OPERATION OF SUPPLY BEYOND RATED OUT-
PUT
(
load ?or each position of the VOLTAGE RANGE
switch. It also shows how the output voltage de-
I
creases toward zero as the current increases
I
above the 7. 5 rnA limiting current.
I
3-11 The shaded area on the front panel meter
I
face indicates the amount of output voltage that is
I
available in excess of the normal rated output.
MthoJgh the supply can be operated in this shaded
I
region without being damaged, it cannot be guar-
I
anteed to meet all its performance specifications.
I
However, if the line voltage is maintained above
I
11 5 Vac, the supply will probably operate within
I
its specifications.
I
3-12 CONNECTING LOAD
3-1 3 Output terminals are provided on the front
panel of the power supply. The terminals are
I
marked + and -.
The positive or negative output
I
terminal may be grounded by shorting the center
pin ahd case of the applicable UG-931/U plug or
I
by grounding the wire from the plug to the chassis,
I
or neither grounded (floating operation; permitted
to 2,600 Vdc off ground).
WARNING
To avoid injury to personnel
due to arcing, turn-off the
power supply before connecting
or disconnecting the load con-
3-14 Each load should be connected to the power
supply output terminals using separate pairs of
connecting wires. This will minimize mutual
coupling effects between loads and will retain full
advantage of the low output impedance of the pow-
er supply. Each pair of connecting wires should
be as short as possible to reduce noise pickup; in
addition, a 0.1 to 1.0 pf capacitor should be con-
nected between one terminal andthe chassis, if
the supply
is floated off of ground.
3-15 If load considerations require that the output
power distribution terminals be remotely located
from the power supply, then the power supply out-
put terminals should be connected to the remote
distribution terminals via a pair of twisted or
shielded wires and each load separately connected
to the remote distribution terminals.
A 0. 1 to 1 pf
capacitor should be connected across the remote
distribution terminals to reduce high frequency
coupling and noise.
3-1 6 OUTPYJT CAPACITANCE
3-17 An internal capacitor, across the output ter-
minals of the power supply, helps to supply high-
current pulses of short duration during constant
voltage operation. Any capacitance added exter-
nally will improve the pulse current capability, but
will decrease the safety provided by the current
limiting circuit.
A high-current pulse may damage
load components before the average output current
is large enough to cause the current limiting cir-
cuit to operate.

3-1 8 REVERSE CURRENT LOADING
3-19 Active loads connected to the power supply
may actually deliver a reverse current to the power
supply during a portion of it's operating cycle. An
external source cannot be allowed to pump current
into the supply without loss of regulation and pos-
sible damage to the output capacitor. To avoid
these effects, it is necessary to preload the supply
with a dummy load resistor sothat the power supply
delivers current through the entire operating cycle
of the load device.
3-2 0 REVERSE VOLTAGE LOADING
.3-21 A diode is connected across the output ter-
minals. Under normal operating conditions, the
diode is reverse biased (anode connected to nega-
tive terminal). If a reverse voltage is applied to
the output terminals (positive voltage applied to
negative terminal), the diode will conduct, shunt-
ing current across the output terminals and limiting
the voltage to the forward voltage drop of the
diode. This diode protects the series transistors
and the output electrolytic capacitors.

SECTION IV
PRINCIPLES OF
0 PERATION
i
CURRENT FEEDBACK
Figure 4-1. Overall Block Diagram
) -5DV
) -32V
) -0.7V
62VAC
4-1
OVERALL BLOCK DISCUSSION (Figure 4-1)
REFERENCE
4-2 Model 6515A, as illustrated in Figure 4-1,
is a high voltage series SCR regulated supply.
I
The input line voltage is stepped up and down by
I
special power transformer T1, a voltage regulating
I
transformer, sometimes referred to as a saturable
I
reactor. T1 provides good regulation against line
I
and load changes.
I
AC
POWER
4-3 The rectifiers and filters convert the ac to
I
raw d~ current which is coupled through CRlO to
the
(-I) output terminal. The regulator, part of the
feedbeck loop is a reversed biased SCR referred to
I
as a remote base transistor. It is made to alter
I
its conduction to maintain a constant output volt-
age.
h he output voltage is adjusted by the VOLT-
AGE
RANGE switch and the VERNIER control. Any
I
instantaneous changes in the output voltage,
I
caused by a change in the load current, are sensed
atthd VERNIER control. The changes are amplified
I
by the voltage input circuit and the driver, and
I
applied to the SCR series regulator to counteract
4-4 The current limit circuit senses the voltage
drop across the current sampling resistor. When
this voltage exceeds a preset limit the current
limit circuit couples a signal to the driver which
limits the conduction of CR10.
u MA1N +585V -
DC
--
+965V . VOLTAGE
+1345V RANGE
+
-
0
+1725V SWITCH
s2
s
Tt-
VOLTAGE FEEDBACK
SUPPLY
4-5 The reference regulator provides stable ref-
erence voltages which are used throughout the unit
for biasing and comparison purposes.
- ) t1.4V
* +2.2v
4-6 DETAILED ClRCUIT ANALYSIS (Refer to over-
all schematic diagram atrear of manual)
4-7 The regulating feedback loop, consisting of
programming resistors R1 through R15 and R21,
voltage input circuit, driver, current limit circuit,
and series SCR regulator CR10, functions continu-
ously to maintain the output voltage constant
during constant voltage operation and the output
current ata safe limit during current limit opera-
tion.
4-8 For purposes of this discussion, assume that
the unit is in constant voltage operation and that
CURRENT
LIMIT
CIRCUIT
ZOOVAC
h
SUPPLY
BIAS
- -lV
--m +9v
-
CRlO CURRENT SAMPLING
SERIES REGULATOR RESISTOR
-
L1
PIGGYBRCK
*Ail - - - -
7
- - 0
SUPPLY
I !L
CR28
-
DRIVER
6
VOLTAGE INPUT
6'
94
CIRCUIT
0 - 16UOV
165OVAC
- Ql 6 92 0 - 5mA

the programming resistors have been adjusted so
that the supply is yielding the desired output
voltage. Further assume that the
(-) side of the
supply is ground (common) and that the output
voltage instantaneously rises (goes positive) due
to a variation in the external load circuit.
4-9 Note that the change may be in the form of a
slow rise in the output voltage or a positive going
ac signal. An ac signal is coupled to the base of
Q1 by capacitor C1 and a dcvoltage is coupled by
R21.
4-10 The instantaneous rise in output voltage
causes the base of Q1 to go positive. Q1 now in-
creases its conduction and its collector voltage
goes negative. The negative going error voltage
is amplified and inverted by Q2 and Q4, and
coupled to the gate of CR10. The negative going
input causes CRlO to decrease its conduction so
that it drops more of the filtered dc, and reduces
the output voltage to its original level.
4-11 If the external load resistance is decreased
to a point where the load current exceeds the
value selected by the current limit potentiometer
R24, the negative voltage on the collector of Q1
forward biases CR7. Thus, the collector of Q7 is
clamped atthe negative voltage on the arm of
potentiometer R24 and the output current is main-
tained at a constant safe maximum. Any further
decreases in load resistance causes the output
voltage to decrease proportionally. The range of
potentiometer R24 enables current limiting be-
tween 5 and 10 +1
mA.
4-12 MAIN DC SUPPLY
4-13 The 0-1 600 Vdc output
is generated by the
main dc supply which consists of five low voltage
supplies in series. The five supplies are CR31-
CR34 (205V), CR11-CR13 (380V), CR12-CR14
(380V), CR15-CR17 (380V), CR16-CR18
( 380V).
The negative side of the 205 volt supply is con-
nected to the regulator CR10, and four positive
voltages, +585, +965, +1345, and +I725 volts are
connected through the VOLTAGE RANGE switch S2
to the
(+) output terminal. By switching the output
voltage in four steps, the voltage across series
regulator CRlO never exceeds 585 volts. Diode
CR28 protects the supply when the output is short
circuited. When the supply in delivering greater
than 585 volts and the output is shorted, the
anode of CR28 becomes more positive than +585V.
Load current flows through CR28 and R33; and
depending on the position of S2, current may flow
through R30, R31, or R32. Resistor R33 determines
the maximum short circuit current that flows
through CR28.
4-1 4 SERIES REGULATOR
4-15 The conduction of the series regulator is
controlled by the feedback voltage obtained from
the driver. The conduction is varied to provide a
voltage drop, which is subtracted from the main
dc supply that results in the selected voltage
available at the output terminals. Silicon Con-
trolled Rectifier CRlO
is a standard SCR used in a
reverse bias configuration, referred to as a remote
base transistor. The name is derived from the ap-
plication and mechanical structure of the device.
The gate lead in an SCR is one junction removed
from the anode.
4-16 In this reverse bias configuration the SCR
is
always conducting and the characteristics are
similar to a high voltage transistor with less than
unity gain.
4-17 Diode CR8, connected across the series reg-
ulator, protects it against reverse voltages that
could occur during parallel operation, if one supply
is turned on before the other.
4-1 8 CONSTANT VOLTAGE INPUT CIRCUIT
4-1
9 This circuit (Q1 and Q2) continuously com-
pares a fixed voltage received from the reference
circuit with a portion of the output voltage and, if
a difference exists, produces an error voltage
whose amplitude and phase is proportional to the
difference.
4-20 Diode CR1 prevents the emitter of Q1 from
going more positive than circuit common (-S).
This condition occurs when the output voltage is
turned down (down programmed) rapidly. Diode
CR3 prevents the base of Q1 from exceeding -0.7V
in the negative direction. When the output volt-
age
is turned up rapidly it drives the base of Q1
negative. Network C3 and R18 provid'e some neg-
ative feedback from collector to base to eliminate
the posibility of oscillations.
4-2 1 DRIVER CIRCUIT
4-22 This circuit receives inputs from either the
voltage input circuit or the current limit circuit.
In constant voltage mode, driver Q4 maintains
CRlO at the correct conduction level so that CRlO
drops a sufficient voltage to hold the output con-
stant. However, when the output current exceeds
the current limit setting,the voltage at the arm of
R24 forward biases CR7 and applies a negative
voltage at the base of
Q4.
Transistor Q4 and CRlO
are held in steady conduction until the external
load is removed.

ed to the -40V reference voltage. Resistors R36
and R37 are selected to provide precisely the cor-
rect programming current. Procedures for select-
ing these resistors are included in the adjustment
and calibration paragraphs in Section
V, Mainte-
nance.
4-24 'dhis circuit supplies regulated dc bias volt-
I
ages to the voltage input circuit and -32V prograrn-
I
rning voltage to VERNIER control R21. Diodes CR21
I
througq CR24 and capacitor C10 rectify and filter
the 62 Vac developed across the secondary of T1. 4-25 Diodes CR20 and CR29 protect the constant
current amplifier against excessive voltage ex-
cusions at the collector. With CR20 connected
to
-64V and CR29 connected to -S, the collector of
Q4 cannot swing beyond +O.
7 to -64V.
The 66
tied to Vdc is regulated by transistor Q5 which is
6. 2 V zener diode VR1. Various regulated
dc outputs are developed across
a series string of
diodes1~~2,CR19, CR20, CR2
, CR4, CR5. and
CR6. The -32
V programming voltage is developed
I
by constant current amplifier Q6 which is connect-

SECTION V
MAINTENANCE
5-1 INTRODUCTION
5-2 Upon receipt of the power supply, the per-
formance check (Paragraph 5-8) should be made.
This check
is suitable for incoming inspection. If
a fault
is detected in the power supply while mak-
ing the performance check or during normal opera-
tion, proceed to the troubleshooting procedures
(Paragraph 5-30). After troubleshooting and repair
(Paragraph 5-37), perform any necessary adjust-
ments and calibrations (Paragraph 5-39). Before
returning
the power supply to normal operation,
repeat the performance check to ensure that the
fault has been properly corrected and that no other
faults exist. Before doing any maintenance
checks, turn-on power supply, allow a half-hour
warm-up, and read the general information regard-
ing measurement techniques (Paragraph 5- 3).
5-3 MEASUREMENT TECHNIQUES
5-4 All measurements qiven in this manual are
with a positive power supply output (negative ter-
minal grounded to chassis). When measuring per-
formance of the power supply it
is important that
the connection to the output terminal does not in-
troduce additional resistance. For voltage meas-
urements, use a T-connector at the positive output
terminal and connect the load to one output of the
T-connector and the measuring device to the other
output of the T-connector. For current measure-
ments, connect a four-terminal current monitoring
resistor in series with the load resistor and con-
nect both to one output of the T-connector. Con-
nect the measuring device across the current mon-
itoring resistor.
5-5 When using an oscilloscope, ground the case
atthe same ground point as the grounded terminal
of the power supply. Make.certain that the case
is
not also grounded by some other means (power cord).
Connect both oscilloscope input leads to the power
supply ground and check that the oscilloscope
is
not exhibiting a ripple or transient due to ground
loops, pick-up or other means.
5-6 TEST EQUIPMENT REQUIRED
5-7 Table 5-1 lists the test equipment required
to perform the various procedures described in
this section.
Table 5-1. Test Equipment
Type
AC Voltmeter
Variable
Voltage
Transformer
0s cilloscope
Differential
Voltmeter
Repetitive
Load Switch
Resistive
Load
Resistor
Required
Characteristics
Accuracy: 2%. Sensitivity: 1mv
full scale (min.
).
Range: 90-1 30 volts. Equipped
with voltmeter accurate within
1 volt, 1 KW rating.
Sensitivity:
1 mv/cm (min. ).
Sensitivity: lmv full scale (min.).
Rate: 60-400
Hz, 2p.sec rise and
fall time, 250V, 1A.
320K, 10W
1 Kn, *1% 2 W non-inductive.
Use
Measure AC voltages
Vary and measure AC
input voltage
Measure ripple and
transient response
Measure regulation;
Calibrate meter
Measure transient
Power supply load
Measure impedance
Recommended
Model
@) 403 B
----
@ 140 A plus
1400
A Plug-in.
@ 3420
See Note
See Figure 5-3
----
----

5-8 PERFORMANCE TEST
5-9 The following test can be used as an incom-
ing inspection check and appropriate portions of
the test can be repeated either to check the oper-
ation of the instrument after repairs or for periodic
preventive maintenance tests.
5-10 The performance check
is made using a 115-
volt, 60-Hz (cps), single-phase input power
source. The performance check
is normally made
at a constant ambient room temperature. The tem-
perature range specification can be verified by do-
ing the performance check (except temperature
stability check) at a controlled temperature of
O°C and at a controlled temperature of 50°C. If
the correct result
is not obtained for a particular
.
check, do not adjust any controls; proceed to
troubleshooting.
5-1
1 RATED OUTPUT, METER, AND OUTPUT
CONTROLS ACCURACY
5-12 Voltage. To check the accuracy of the out-
put voltage, front panel voltmeter, and front
panel voltage controls, proceed as follows:
a. Connect the differential voltmeter, load
resistor, and the attenuator to the power supply as
illustrated in Figure 5-2. Load resistance
is ap-
proximately 320K ohms, 10 watts.
b. Turn the front panel VOLTAGE RANGE
switch and VERNIER control until the front panel
voltmeter indicates exactly 1600 Vdc.
c. The differential voltmeter should indicate
1. 6 h 0. 32 Vdc.
5-1 3 Current.
To check the output current capa-
bility of the supply, proceed as follows:
a. Connect the multimeter (set to the 10
mA
position) or another milliammeter in series with a
320K 10W load resistance, and attach the series
combination to the output terminals.
b. Adjust the VOLTAGE RANGE switch and
VERNIER control until the front panel voltmeter
indicates 1600 Vdc.
c. The multimeter should indicate 5
rnA.
5-1 4 LOAD REGULATION
5-15 To check constant voltage load regulation,
proceed as follows:
a. Connect differential voltmeter, load
resistor and attenuator to the power supply as
illustrated in Figure 5-2.
b. Turn the front panel VOLTAGE RANGE
switch and VERNIER control until the front panel
voltmeter indicates exactly 1600 volts.
SUPPLY
MODEL 6515A
DIFFERENTIAL
VOLTMETER OR
OSCILLOSCOPE
Figure 5-2. Line and Load Regulation, Test Setup
c. Read and record voltage indicated on
differential voltmeter.
d. Disconnect load resistor.
e. Reading on differential voltmeter should
not vary from reading recorded in step
c by more
than 160 mV.
5-1 6 LINE REGULATION
5-17 To check constant voltage line regulation,
proceed as follows:
a. Connect variable auto-transformer be-
tween input power source and power supply power
input. b. Connect differential voltmeter, load re-
sistor, and attenuator
as illustrated in Figure 5-2.
c. Adjust variable auto-transformer for 105
Vac input.
d. Adjust front panel VOLTAGE RANGE
switch and VERNIER control until the front panel
voltmeter indicates exactly 1600 Vdc.
e. Read and record voltage indicated on
differential voltmeter.
f. Adjust variable auto transformer for 125
Vac input.
g.
Reading on differential voltmeter should
not vary from reading recorded in step e by more
than 160 mV.
5-1
8 RIPPLE AND NOISE
5-19 To check the ripple and noise, proceed as
follows:
a. Connect 320K ohm, 10W load resistor to
the power supply output.
b. Connect the oscilloscope (in series with
a lpf capacitor rated for at least 1600 Vdc) to the
power supply output.