KEPCO HSM 24-42 User manual

IMPORTANT NOTES:
1) This manual is valid for the following Model and associated serial numbers:
MODEL SERIAL NO. REV. NO.
2) A Change Page may be included at the end of the manual. All applicable changes and
revision number changes are documented with reference to the equipment serial num-
bers. Before using this Instruction Manual, check your equipment serial number to identify
your model. If in doubt, contact your nearest Kepco Representative, or the Kepco Docu-
mentation Office in New York, [phone], requesting the correct revision for your
particular model and serial number.
3) The contents of this manual are protected by copyright. Reproduction of any part can be
made only with the specific written permission of Kepco, Inc.
Data subject to change without notice.
KEPCO®
THE POWER SUPPLIER™
MODEL
OPERATOR’S MANUAL
KEPCO INC.
KEPCO, INC. z131-38 SANFORD AVENUE zFLUSHING, NY. 11355 U.S.A. zTEL [phone] zFAX [phone]
email: [e-mail] zWorld Wide Web: http://www.kepcopower.com
An ISO 9001 Company.
©2012, KEPCO, INC
P/N 243-0850b
HSM SERIES
1000 AND 1500 WATT SWITCHING POWER SUPPLY
VOLTAGE/CURRENT-STABILIZED DC SOURCE
HSM SERIES
POWER SUPPLY

HSM OPR 052912 i
TABLE OF CONTENTS
SECTION PAGE
SECTION 1 - INTRODUCTION
1.1 Scope of Manual ..................................................................................................................................... 1-1
1.2 General Description................................................................................................................................. 1-1
1.3 Specifications .......................................................................................................................................... 1-1
1.4 Miscellaneous Features .......................................................................................................................... 1-5
1.4.1 Control/programming......................................................................................................................... 1-5
1.4.2 Status Flags:...................................................................................................................................... 1-5
1.4.3 Setpoint Monitors:.............................................................................................................................. 1-5
1.4.4 Remote Error Sensing: ...................................................................................................................... 1-5
1.4.5 Load Sharing: .................................................................................................................................... 1-5
1.4.6 Load Monitor:..................................................................................................................................... 1-5
1.4.7 Auxiliary Supply: ................................................................................................................................ 1-5
1.4.8 Overcurrent/undervoltage Protection:................................................................................................ 1-5
1.4.9 Current Walk-in:................................................................................................................................. 1-5
1.4.10 Remote Reset:................................................................................................................................... 1-5
1.5 Options .................................................................................................................................................... 1-6
1.5.1 Battery Charger (B Suffix):................................................................................................................. 1-6
1.6 Accessories ............................................................................................................................................. 1-6
SECTION 2 - INSTALLATION
2.1 Unpacking and Inspection ....................................................................................................................... 2-1
2.2 Terminations and Controls ...................................................................................................................... 2-1
2.3 Source Power Requirements .................................................................................................................. 2-3
2.4 Cooling .................................................................................................................................................... 2-3
2.5 Preliminary Operational Check................................................................................................................ 2-3
2.6 Installation ............................................................................................................................................... 2-4
2.7 Wiring Instructions................................................................................................................................... 2-4
2.7.1 Safety Grounding............................................................................................................................... 2-4
2.7.2 Source Power Connections ............................................................................................................... 2-4
2.7.3 D-C Output Grounding....................................................................................................................... 2-5
2.7.4 Power Supply/Load Interface............................................................................................................. 2-5
2.7.5 Load Connection - General................................................................................................................ 2-6
2.7.5.1 Load Connection - Method I (Local Error Sensing)...................................................................... 2-7
2.7.5.2 Load Connection - Method II (Remote Error Sensing)................................................................. 2-8
2.7.5.3 Load Connection - Method III (Series Connection)...................................................................... 2-9
2.7.5.4 Load Connection - Method IV (Parallel/Redundant Operation) ................................................... 2-10
2.7.6 Load Sharing ..................................................................................................................................... 2-11
2.7.7 Signal Connections............................................................................................................................ 2-12
SECTION 3 - OPERATING INSTRUCTIONS
3.1 Operating Configuration .......................................................................................................................... 3-1
3.2 Remote Error Sense................................................................................................................................ 3-1
3.3 Output Voltage Programming.................................................................................................................. 3-1
3.4 Output Voltage Range............................................................................................................................. 3-2
3.5 Current Limit Programming ..................................................................................................................... 3-2
3.6 Current Limit Programming Range.......................................................................................................... 3-3
3.7 Setpoint Monitors .................................................................................................................................... 3-3
3.8 Overvoltage Protection Adjustment......................................................................................................... 3-4
3.9 Current Limit Characteristic..................................................................................................................... 3-5
3.10 Current Walk-in Circuit ............................................................................................................................ 3-6
3.11 5VAUX Floating Supply ........................................................................................................................... 3-6
3.12 Remote Inhibit/Remote Reset Controls................................................................................................... 3-7

ii HSM OPR 052912
TABLE OF CONTENTS
SECTION PAGE
3.13 Module Current Monitor .......................................................................................................................... 3-7
3.14 Status Flags............................................................................................................................................ 3-8
3.14.1 Source Power Status Flags .............................................................................................................. 3-8
3.14.2 OUTPUT Status Flags ...................................................................................................................... 3-9
3.14.3 OVERTEMP Status Flags................................................................................................................. 3-10
3.14.4 FANFAIL Status Flags ...................................................................................................................... 3-10
1-1 HSM Series Power Supply ........................................................................................................................... iv
1-2 Temperature Derating ................................................................................................................................ 1-3
1-3 Outline Drawing.......................................................................................................................................... 1-4
2-1 HSM Series Output Controls and Configuration Switch Functions ............................................................ 2-1
2-2 HSM Series Rear Panel Connections ........................................................................................................ 2-2
2-3 Load Connection - Method I (Local Error Sensing).................................................................................... 2-7
2-4 Load Connection - Method II (Remote Error Sensing) ............................................................................... 2-8
2-5 Load Connection - Method III (Series Connection) .................................................................................... 2-9
2-6 Load Connection - Method IV (Parallel/Redundant Operation wit Hot Swap ............................................. 2-10
3-1 External Resistance Programming of Output Voltage................................................................................ 3-2
3-2 External Voltage Programming of Output Voltage ..................................................................................... 3-2
3-3 External Voltage Programming of Current Limit......................................................................................... 3-3
3-4 Current Walk-In Characteristic ................................................................................................................... 3-6
3-5 Remote Inhibit Control Operation............................................................................................................... 3-7
3-6 Timing Diagram for POWER and DCFAIL Status ...................................................................................... 3-9
1-1 Model Parameters ...................................................................................................................................... 1-1
1-2 General SpecificationS ............................................................................................................................... 1-2
1-3 Accessories ................................................................................................................................................ 1-6
2-1 Configuration Controls ................................................................................................................................ 2-1
2-2 I/O Connector Pin Assignments ................................................................................................................. 2-2
3-1 Status Flags ............................................................................................................................................... 3-8
3-2 Fault Detector Operation ............................................................................................................................ 3-10
LIST OF FIGURES
FIGURE PAGE
LIST OF TABLES
TABLE PAGE

(iii Blank)/iv HSMSERIES OPR 052912
FIGURE 1-1. HSM SERIES POWER SUPPLY

HSMSERIES OPR 052912 1-1
SECTION I - INTRODUCTION
1.1 SCOPE OF MANUAL
This manual contains instructions for the installation and operation of the HSM series of voltage
and current stabilized d-c power supplies manufactured by Kepco, Inc., Flushing, New York,
U.S.A.
1.2 GENERAL DESCRIPTION
The HSM power supply is basically a voltage and current stabilized d-c source with a relatively
sharp crossover between voltage and current mode operation. This permits HSMs to be used
both as conventional regulated voltage sources and in applications such as battery chargers,
where automatic crossover between constant voltage and constant current operation is
required.
HSM power supplies are supplied in a single mechanical size and are nominally rated at either
1000 or 1500 watts of output power. HSM 1000 watt power supplies are designed to operate
over the universal a-c power mains voltage range of 90-277V (47-63Hz), with operation from
125-420V d-c also available. HSM 1500 watt products provide full power over the a-c mains
range of 180-277V a-c, with output power derating linearly to 1000 watts as a-c mains voltage
drops from 180 to 90V a-c. Active power factor correction circuitry limits source current harmon-
ics to negligible levels, significantly improving source power utilization. Cooling is provided via
an internal d-c fan.
The HSM permits adjustment of both output voltage (VO) and current limit (IMAX), either by
internal (pot) or external (resistance or voltage) methods; programming method is selected via
DIP switches accessed through the top of the unit. Independent circuitry provides protection
against overvoltage, overcurrent and overtemperature failures; fault detection circuitry monitors
performance of the output and critical internal functions, providing both visual and electrical indi-
cators. A switch-selectable "current walk-in" circuit and optional float/equalize functions
enhance the performance of HSM power supplies for such applications as battery chargers
The HSM power supply is designed for fixed installation applications where the load connec-
tions are hard-wired to the power supply. Forced current sharing and unique internal fault detec-
tion circuitry permits straight paralleling in redundant power applications with or without output
blocking diodes. Kepco RA 58 (or similar) rack adapters are available for EIA standard rack
mounting. For applications requiring plug-in or hot-swap power supply modules refer to Kepco
HSP Series power supplies.
1.3 SPECIFICATIONS
Table 1-1 below indicates specifications for parameters that vary for different HSM models;
Table 1-2 lists general specifications that apply to all HSM models.
TABLE 1-1. MODEL PARAMETERS
MODEL
OUTPUT VOLTAGE
(Volts)
OVP
SETTING
(Volts)
OUTPUT CURRENT
(Amps)
RIPPLE
(mV p-p)
NOISE
(mV p-p)
EFFICIENCY
(Percent)
(See Note 1.)
Nominal
(Factory
Set)
Adjust-
ment Range
Factory
Setpoint 50° C 60° C 71°C Source max
Switching
max
(Spike)
20MHz
100% Load
115V a-c
HSM 3.3-230 3.3 0.7-3.6 4.29 230 173 105 20 30 100 71
HSM 5-200 5 1.0-5.5 6.5 200 150 95 20 30 100 72
HSM 12-84 12 2.4-13.2 15.6 84 63 40 20 40 120 73
HSM 15-66 15 3.0-16.5 19.5 66 49.5 31.4 20 40 150 76
HSM 24-42 24 4.8-26.4 31.2 42 31.5 20 20 60 240 77
HSM 28-36 28 5.6-30.8 36.4 36 27 17 20 60 280 78
HSM 48-21 48 9.6-59.2 62.4 21 16 10 20 60 480 80
HSM 24-60 24 4.8-26.4 31.2 60 45 28.6 20 60 120 77
HSM 28-53 28 5.6-30.8 36.4 53 39.8 25.2 20 60 140 78
HSM 48-30 48 9.6-59.2 62.4 30 22.5 14.3 20 60 240 80
1. “R” Model efficiency is typically 2-3% lower.
1000 Watts
1500 Watts

1-2 HSMSERIES OPR 052912
TABLE 1-2. GENERAL SPECIFICATIONS
CHARACTERISTIC REQUIREMENT
SOURCE INPUT
Source Voltage
AC: Single-Phase,
1000W 1500W
Nominal : 100-250V rms 200-250V rms
Range: 90-277Vrms 180-277V rms
DC: 125-420V d-c (polarity insensitive) †
Brownout Voltage 1000W:75 V a-c typ.
1500W:150 V a-c typ.
Source Frequency
47-440 Hz (Frequencies in excess of 63Hz
will cause leakage current to exceed limits
specified below)
Current
120V a-c 11A rms max
240V a-c 1000W: 5.5A rms max
1500W: 8.0A rms max
Power Factor
0.99 typical; 0.96 minimum for all source
conditions and loads from 25% to 100% of
rated load.
Inrush Current 75A max
Efficiency See Table 1-1.
Withstand Voltage
(See Note 2)
3000V rms Input to Output
1500V rms Input to Case
500V d-c Output to Case
Leakage Current
<0.50mA @ 115V a-c, 47-63Hz
<1.0mA @ 230V a-c, 47-63Hz
Safety
Agency
Approvals
UL Recognized (SELV)
UL 1950 / UL1459 Para. 35A.1
CSA Certified (SELV)
CSA 22.2 No. 234-M90 (Level 5)
Immunity
(See Note 3)
Radiated RF (Ampl. Mod.) (ENV50140)
10V/m, 80-1000MHz
Radiated RF (Pulse Mod.) (ENV50204)
(Pulse) 10V/m, 900MHz
Magnetic Field (EN 61000-4-8)
30A/m, 50Hz
Electrostatic Discharge (EN 61000-4-2)
Contact: 4KV, Air: 8KV
Conducted RF (ENV50141)
10Vrms, 0.15-80MHz
Electrical Fast Transient (EN 61000-4-4)
2KV, Tr/Th = 8/20µs
Input Surge (EN 61000-4-5)
Comm. Mode: 2KV; Diff. Mode: 2KV
Emissions
Conducted RF (CISPR 22)
Class A Limits, 0.15-30MHz
Current Harmonics (EN 61000-3-2)
0-2KHz, any source/load condition)
CHARACTERISTIC REQUIREMENT
OUTPUT/LOAD
Nominal Voltage See Table 1-1.
Rated Current See Table 1-1.
Minimum Output
Current
2% of rated load (lower output conditions may
result in increased output ripple and increased
transient response recovery time).
Output Voltage Range See Table 1-1.
Regulation Error
Source Effect 0.1% over full source
voltage range
Load Effect 0.1% from 5% to 100% of
rated load
Temperature
Effect 0.02%/°C, 0°C<TA<50°C
Time Effect
(Drift)
0.1%/24 hr period after 30
min. warmup
Combined Effect 0.3%
Ripple and Noise See Table 1-1.
Start-up Time 1 sec maximum at rated output current
Output
Hold-up
Time
21.5 msec transparent power loss (no
indication)
5 msec following power loss indication
>27 msec total time prior to loss of output
regulation
Turn-on/Turn-off Over-
shoot Within load transient response envelope
Load Transient
Response
(25% load transient,
2A/µsec rise/fall time)
Maximum
excursion
3% of nominal output
voltage
Recovery time 100msec return to within 1% of
set voltage
Output Polarity All outputs are floating and can be referenced
as required by the user at up to ±500V d-c.
PROTECTION
Input Fusing Internal fuse, hot line only (not operator
serviceable - refer to Service Manual).
Low A-C Protection HSM Power supplies will self-protect, no fixed
limit.
Overvoltage
Protection
Latched shutdown if output voltage exceeds
user-selected limit (see Operating Instructions,
PAR. 3.8) (see Note 4).
Overcurrent
Protection
Constant current limiting (optional undervol-
tage-activated latched shutdown (see
Operating Instructions, PAR. 3.9) (see Note 4).
Overtemperature
Protection
Thermostat shutdown with hysteretic recovery
and automatic restart.
NOTES:1. Safety Agency approvals for a-c input only
2. 25oC, 65% RH
3. Per EN 50082-2, Acceptance Criteria A
4. Latched shutdown requires that source power be cycled for
restart (optional restart by cycling REMOTE ON/OFF control
signal); see Operating Instructions, PAR. 3.12.

HSMSERIES OPR 052912 1-3
TABLE 1-2. GENERAL SPECIFICATIONS (CONTINUED)
FIGURE 1-1.
FIGURE 1-2. TEMPERATURE DERATING
CHARACTERISTIC REQUIREMENT
SIGNAL AND CONTROL
Remote Error Sensing
3.3V & 5V Models 0.25V per wire
All other Models 0.8V per wire
Remote On/Off Control Isolated TTL-compatible signal; either logic
high or logic low will disable output.
Load Sharing Within 5% of load when connected via load
sharing wire (see PAR. 2.7.6).
Load Monitor 0-5V analog signal proportional to output
load current; 5V at 100% of rated load.
Status Flags
(Form C dry relay contacts)
(See PAR. 3.14.)
(See Notes 5 and 7.)
POWER
Indicates low source
voltage; signal
asserted a minimum of
5 msec prior to loss of
output voltage.
OUTPUT
Indicates HSM Power
Supply in normal
operating mode.
OVERTEMP
Indicates HSM Power
Supply in
overtemperature
shutdown.
FAN FAIL Indicates failure of
internal cooling fan.
Auxiliary Voltage
(Isolated)
4.75-5.25V d-c output, 0 - 100mA,
parallelable, output isolated (500 V d-c),
Input isolated (SELV) (See Operating
Instructions, PAR. 3.11).
Voltage Set Programming
Mode selected by
internal switches
(See Note 6.)
(See PAR. 3.3.)
Internal Multiturn pot
External 1 Resistance: 0-50KΩ
External 2 0-10V, 500µA max
Current Limit
Programming
Internal Multiturn pot
External 0-10V, 500µA max
CHARACTERISTIC REQUIREMENT
ENVIRONMENT
Temperature Range
Operating
0 to 50° C: rated load;
50 ° C to 71 ° C: derat e by
2.5%/° C, see Figure 1-2.)
Storage -40 to +85° C
Cooling Internal d-c fan (inlet, exhaust as indicated in
Figure 1-3).
Humidity 0-95% RH (non-condensing), Operating and
Storage.
Shock Non-operating, 20g, 11msec 50%, half sine, 3
axes, 3 shocks each axis
Vibration
5-10Hz 10mm, double amplitude
10-55Hz 2g
Altitude Sea level to 10,000 feet
PHYSICAL
Dimensions See Figure 1-3.
Weight 16 lbs. (7.3Kg)
Source Connections 3-pin power entry module (compatible with IEC
320/C19 molded line cord plug.
Load Connection Two bus bars (+ and -)1.0 x 0.125 inch, copper
w/bright nickel finish
Signal Connection 37-pin D-subminiature connector (male)
NOTES 5: Status flags are isolated and operate independently.
6: The POWER/DCFAIL fault detector window tracks pro-
grammed output voltage, however, the overvoltage protection
trip point remains unaffected.
7. Form C contacts: rated from 30V d-c/1A to 60V d-c/0.3A.

1-4 HSMSERIES OPR 052912
FIGURE 1-3. OUTLINE DRAWING

HSMSERIES OPR 052912 1-5
1.4 MISCELLANEOUS FEATURES
1.4.1 CONTROL/PROGRAMMING a)VOLTAGE CHANNEL: Output voltage is controlled continu-
ously throughout the specified adjustment range via a 10-turn potentiometer accessed
through the top cover. External control can be exercised either by resistance or by control
voltage (see PAR.s 3.3 and 3.4).
b) CURRENT CHANNEL: Output current is controlled continuously throughout the specified
adjustment range via a 10-turn potentiometer accessed through the top cover. External
control can be exercised by control voltage (see PAR.s 3.5 and 3.6).
c) OVERVOLTAGE LEVEL: The output voltage level at which the overvoltage protection
latch is activated may be adjusted locally via a 10-turn potentiometer accessed through the
top cover (see PAR. 3.8).
d) REMOTE INHIBIT: Operation of the output regulator can be inhibited remotely via either
one of two TTL-level control lines, RC1 and RC2. Both of these signals are isolated from
both the input and output, allowing single-point control of several power supplies operating
at different potentials. Both positive and negative logic are supported (see PAR. 3.12).
1.4.2 STATUS FLAGS: Four sets of Form C dry relay contacts (3 wires each) are provided at the I/O
connector which duplicate the front panel status indicator functions (see PAR. 3.14).
1.4.3 SETPOINT MONITORS: Analog voltage signals which display programmed output voltage and
current limit values. These signals are available at the I/O connector (VSET and ISET). Signals
are referenced to negative error sense (see PAR. 3.7).
1.4.4 REMOTE ERROR SENSING: Separate voltage sensing connections permit 4-wire connection
to load. Will compensate for static load effects due to power lead d-c resistance (DCR) up to
specified maximum voltage drop per load lead at maximum specified output voltage (see PAR.
3.2).
1.4.5 LOAD SHARING: Bidirectional control port provides forced load sharing between two or more
power supplies wired in parallel (see PAR. 2.7.6).
1.4.6 LOAD MONITOR: Analog voltage signal which indicates actual load current delivered by the
power supply (see PAR. 3.13).
1.4.7 AUXILIARY SUPPLY: Logic-level secondary output provides up to 0.5 watts of power at 5V
d-c. This output is isolated from the output and is unaffected by the status of the main output.
Provides power for external Remote Inhibit controls (see PAR. 3.11).
1.4.8 OVERCURRENT/UNDERVOLTAGE PROTECTION: Switch-selectable option provides the
user load protection against long-term output overloads or undervoltage conditions (see PAR.
3.9).
1.4.9 CURRENT WALK-IN: Switch-selectable option provides control of output current rise rate
based on Bellcore TR-TSY-000947 requirements for battery chargers (see PAR. 3.10).
1.4.10 REMOTE RESET: Switch-selectable option provides capability to reset the latch used by the
overvoltage protection circuitry to disable the output regulator, using the Remote Inhibit control
lines (see PAR. 3.12).

1-6 HSMSERIES OPR 052912
1.5 OPTIONS
HSM options are described below:
1.5.1 BATTERY CHARGER (B SUFFIX): The battery charger option incorporates an expanded
window for the output voltage fault detector compatible with normal battery operating voltages.
1.6 ACCESSORIES
Accessories for HSM Power Supplies are listed in Table 1-3.
TABLE 1-3. ACCESSORIES
ACCESSORY PART
NUMBER USE
RACK
ADAPTERS
RA 58 Accommodates up to three Power Supplies in a 19-inch rack. Used for hard-wired applications
only.
RA 61 Same as RA 58 except accommodates up to four Power Supplies in a 24-inch rack for hard-
wired applications.
RACK
ADAPTER
OPTIONS
-23E Incorporates wider mounting ears to accommodate a 23-inch rack; available for all 19-inch rack
adapters above.
-24E Incorporates wider mounting ears to accommodate a 24-inch rack; available for all 19-inch rack
adapters above.
SERIES
CLAMPING
DIODES
124-0600
Used with HSM 24V, 28V and 48V models when wired for series operation. User must provide
wiring and heat sink. One diode required for each power supply. See PAR.2.7.5.3. May also be
used as optional external blocking diode for redundant applications. See PAR. 2.7.5.4.
124-0601
Used with HSM 3.3V, 5V, 12V and 15V models when wired for series operation. User must pro-
vide wiring and heat sink. One diode required for each power supply. See PAR. 2.7.5.3. May
also be used as optional external blocking diode for redundant applications. See PAR. 2.7.5.4.
CONNECTORS
142-0422* I/O connector mating plug
142-0381* Source power inlet connector mating plug (IEC 320-C19)
118-0776 North American linecord set (NEMA 5-20P to IEC 320-C19)
108-0294 I/O connector backshell
108-0203 I/O connector jackposts (set of two)
FIXED
INSTALLATION
KIT
219-0240 Standard - Kit consists of North American linecord set, I/O connector mating plug, I/O connec-
tor backshell, I/O connector jackposts, and screws for fixed mounting.
219-0249 Customer-wired - Same as Standard Kit (Part No. 219-240), except linecord is replaced with
user-wired AC power inlet mating plug.
SCREW 101-0159 Used for fixed mounting of HSM Power Supply (#6-20, 0.625 in. long).
* Item (quantity 1) supplied with unit.

HSMSERIES OPR 052912 2-1
SECTION 2 - INSTALLATION
2.1 UNPACKING AND INSPECTION
This instrument has been thoroughly inspected and tested prior to packing and is ready for
operation. After careful unpacking, inspect for shipping damage before attempting to operate.
Perform the preliminary operational check as outlined in PAR. 2.5. If any indication of damage
is found, file an immediate claim with the responsible transport service.
2.2 TERMINATIONS AND CONTROLS
a) Output and Configuration Controls: Refer to Figure 2-1 and Table 2-1.
b) Rear Panel: Refer to Figure 2-2 and Table 2-2.
FIGURE 2-1. HSM SERIES OUTPUT CONTROLS AND CONFIGURATION SWITCH FUNCTIONS
TABLE 2-1. CONFIGURATION CONTROLS
SW
POSITION FUNCTION REF. PAR.
S1-1 REMOTE LOCKOUT RESET 3.12
S1-2 CURRENT WALK-IN 3.10
S1-3 UNDERVOLTAGE LOCKOUT 3.9
S2-1 RANGE SELECT (VOLTAGE LOOP) 3.4
S2-2 RANGE SELECT (FAULT DETECTOR) 3.4
S2-3 EXT. VOLT. PROG. (VOLTAGE LOOP) 3.3
S2-4 EXT. RES. PROG. (VOLTAGE LOOP) 3.3
S2-5 INT. PROG. (VOLTAGE LOOP) 3.3
S3-1 RANGE SELECT (CURRENT LOOP) 3.6
S3-2 EXT. VOLT. PROG. (CURRENT LOOP) 3.5
S3-3 INT. PROG. (CURRENT LOOP) 3.5

2-2 HSMSERIES OPR 052912
FIGURE 2-2. HSM SERIES REAR PANEL CONNECTIONS
TABLE 2-2. I/O CONNECTOR PIN ASSIGNMENTS
PIN NO. NAME DESCRIPTION OF FUNCTION REF. PAR.
1 X NO CONNECTION
2 X NO CONNECTION
3 FFS-1 FAN STATUS - NORMALLY CLOSED CONTACT 3.14
4 ACS-C SOURCE POWER STATUS - COMMON CONTACT 3.14
5 ACS-2 SOURCE POWER STATUS - NORMALLY CLOSED CONTACT 3.14
6 X NO CONNECTION (SEE NOTE 1)
7 RC2 REMOTE INHIBIT - NORMALLY LOW INPUT (SEE NOTE 2) 3.12
8 RC1 REMOTE INHIBIT - NORMALLY HIGH INPUT (SEE NOTE 2) 3.12
9 X NO CONNECTION (SEE NOTE 1)
10 X NO CONNECTION
11 OTS-C OVERTEMP STATUS - COMMON CONTACT 3.14
12 PSS-C OUTPUT STATUS - COMMON CONTACT 3.14
13 PSS-2 OUTPUT STATUS - NORMALLY CLOSED CONTACT 3.14
14 ISHARE LOAD SHARE SIGNAL BUS (0-5.5V) (SEE NOTE 3) 2.7.6
15 IPROG ANALOG PROGRAMMING INPUT - CURRENT (0-10V) (SEE NOTE(3) 3.5
16 X NO CONNECTION
17 VRP-1 RESISTIVE PROGRAMMING INPUT (0-10K) 3.3
18 VPROG ANALOG PROGRAMMING INPUT - VOLTAGE (0-10V) (SEE NOTE 3) 3.3
19 -S NEGATIVE ERROR SENSE INPUT 2.7.5
20 X NO CONNECTION
21 FFS-2 FAN STATUS - NORMALLY OPEN CONTACT 3.14
22 FFS-C FAN STATUS - COMMON CONTACT 3.14
23 ACS-1 SOURCE POWER STATUS - NORMALLY OPEN CONTACT 3.14
24 X NO CONNECTION (SEE NOTE 1)
25 AUXRTN AUXILIARY SUPPLY RETURN (SEE NOTE 2) 3.11
26 5VAUX AUXILIARY SUPPLY OUTPUT 3.11
27 X NO CONNECTION (SEE NOTE 1)
28 X NO CONNECTION
29 OTS-2 OVERTEMP STATUS - NORMALLY OPEN CONTACT 3.14
30 OTS-1 OVERTEMP STATUS - NORMALLY CLOSED CONTACT 3.14
31 PSS-1 OUTPUT STATUS - NORMALLY OPEN CONTACT 3.14
32 IMON ANALOG OUTPUT CURRENT MONITOR (0-5.5V) (SEE NOTE 3) 3.13
33 ISET CURRENT LIMIT SETPOINT MONITOR (0-10V) (SEE NOTE 3) 3.7
34 X NO CONNECTION
35 VRP2 RESISTIVE PROGRAMMING INPUT - VOLTAGE (0-10K) 3.3
36 VSET OUTPUT VOLTAGE SETPOINT MONITOR (0-10V) (SEE NOTE 3) 3.7
37 +S POSITIVE ERROR SENSE INPUT 2.7.5
NOTES (1) THESE PINS ARE LEFT BLANK TO PROVIDE VOLTAGE ISOLATION BETWEEN OUTPUT AND 5V AUX SUPPLY
WHICH POWERS THE REMOTE INHIBIT CONTROL CIRCUITRY.
(2) THESE SIGNALS ARE REFERENCED TO AUXRTN (PIN 25).
(3) THESE SIGNALS ARE REFERENCED TO -S (PIN 19).

HSMSERIES OPR 052912 2-3
2.3 SOURCE POWER REQUIREMENTS
This power supply will operate with the installed fuse from single phase a-c mains power over
the specified voltage and frequency ranges without adjustment or modification. Operation from
d-c power is also available; please contact factory for limitations imposed when using d-c
source power.
2.4 COOLING
The power devices used within the HSM power supply are maintained within their operating
temperature range by means of internal heat sink assemblies cooled by an internal cooling fan.
The cooling method utilizes pressurization rather than evacuation, resulting in greater cooling
efficiency and reduced contaminant collection within the enclosure. ALL INLET AND EXHAUST
OPENINGS AROUND THE POWER SUPPLY CASE MUST BE KEPT CLEAR OF OBSTRUC-
TION TO ENSURE PROPER AIR ENTRY AND EXHAUST. Periodic cleaning of the power sup-
ply interior is recommended. If the power supply is rack mounted, or installed within a confined
space, care must be taken that the ambient temperature, which is the temperature of the air
immediately surrounding the power supply, does not rise above the specified limits for the oper-
ating load conditions (see PAR. 1.3 and Figure 1-2).
2.5 PRELIMINARY OPERATIONAL CHECK
A simple operational check after unpacking and before equipment installation is advisable to
ascertain whether the power supply has suffered damage resulting from shipping. Refer to Fig-
ures 2-1 and 2-2 for location of operating controls and electrical connections.
1. THE POWER SUPPLY WILL NOT OPERATE UNLESS THE REMOTE SENSE LINES ARE
PROPERLY CONNECTED TO THE OUTPUT TERMINALS! Connect the remote sense ter-
minals to the output bus bars using the mating I/O Connector (Kepco P/N 142-0422) or other
means as shown in PAR. 2.7.5.1 and Figure 2-3.
2. Connect the power supply to source power as defined in PAR. 1.3. Connection can be made
using either the North American linecord set (Kepco P/N 118-0776) or using a custom line-
cord terminated at one end with an IEC 320/C19 plug (Kepco P/N 142-0381). Follow all
requirements of local electric code regarding wire size, termination, etc.
3. Connect a static load, R, across output terminals. The load value is determined by the nomi-
nal output voltage of the HSM power supply and must be capable of handling 2% of the
power supply output rating (minimum power capability of 20 watts). R is calculated as
approximately equal to output voltage2/20 (R = E2/P). For example, for the HSM 48-21, R =
482/20 = 115.2; use load of 120 ohms, 20 watts.
4. Apply source power; using a DVM, measure the voltage across the output bus bars; this volt-
age is factory set to the value shown in PAR. 1.3. If necessary, adjust the output voltage
using the trim pot labeled "VO" accessed through the top cover.
5. Using the DVM, measure the voltage across I/O connector pins 38 and 19; this voltage
should read 1/10 of the output voltage measured in step 4 above, ±1%.
6. Using the DVM, measure the voltage across I/O connector pins 33 and 19; this voltage is
factory adjusted to 10.0V, and corresponds to 100% of maximum current (see PAR. 3.7). If
necessary, readjust to 10.0V using the trim pot labeled “IMAX” accessed through the top
cover; if desired, readjust for lower current limit (see PAR. 3.7).

2-4 HSMSERIES OPR 052912
7. Disconnect sense lines with power supply still operating, either by removing the mating I/O
connector or by manually opening the sense line connected to Pin 37; verify that the power
supply output turns off (NOTE: At no load the output voltage will drop slowly.)
8. Remove source power for 30 seconds or until fan stops turning; Reconnect the sense lines,
reapply source power; verify that the output voltage returns to the value measured in step 5
above,
9. Remove source power connection.
2.6 INSTALLATION (Refer to Figure 1-3, Outline Drawing)
The HSM power supply is designed to be operated in fixed installation applications. Attach the
HSM power supply to the mounting surface using the four holes in the bottom of the chassis sur-
rounded by plastic grommets.
For all installations, provide adequate clearance around air inlet and exhaust locations and
ensure that the temperature immediately surrounding the unit and especially near the air inlets
does not exceed the maximum specified ambient temperature for the operating conditions.
2.7 WIRING INSTRUCTIONS
Interconnections between an a-c power source and a stabilized power supply, and between the
power supply and its load are as critical as the interface between other types of electronic equip-
ment. If optimum performance is expected, certain rules for the interconnection of source,
power supply and load must be observed by the user. These rules are described in detail in the
following paragraphs.
2.7.1 SAFETY GROUNDING
Local, national and international safety rules dictate the grounding of the metal cover and case
of any instrument connected to the a-c power source, when such grounding is an intrinsic part of
the safety aspect of the instrument. The instructions below suggest wiring methods which com-
ply with these safety requirements; however, in the event that the specific installation for the
power system is different from the recommended wiring, it is the customer's responsibility to
ensure that all applicable electric codes for safety grounding requirements are met.
2.7.2 SOURCE POWER CONNECTIONS
The rear panel of the HSM power supply is equipped with an IEC 320 style recessed power inlet
connector which provides interface to a 3-wire safety line cord via a polarized mating plug.
Kepco offers as accessories (see Table 1-3) both a user-wired mating connector and a prewired
linecord set, the latter configured for North American applications. Terminal assignment follows
internationally accepted conventions (see Figure 2-3). It is the user's responsibility to ensure
that all applicable local codes for source power wiring are met.

HSMSERIES OPR 052912 2-5
WARNING!
IT IS IMPERATIVE THAT THE USER PROVIDE ALL THREE SOURCE
WIRE CONNECTIONS, AS THIS CONNECTION IS THE SAFETY
GROUND PROVISION!
The user- wired mating connector requires size #14 AWG (minimum) conductors for all three
connections.
2.7.3 D-C OUTPUT GROUNDING
Connections between the power supply and the load and sensing connections may, despite all
precautions such as shielding, twisting of wire pairs, etc., be influenced by radiated noise, or
"pick-up". To minimize the effects of this radiated noise the user should consider grounding one
side of the power supply/load circuit. The success of d-c grounding requires careful analysis of
each specific application, however, and this recommendation can only serve as a general guide-
line.
One of the most important considerations in establishing a successful grounding scheme is to
avoid GROUND LOOPS. Ground loops are created when two or more points are grounded at
different physical locations along the output circuit. Due to the interconnection impedance
between the separated grounding points, a difference voltage and resultant current flow is
superimposed on the load. The effect of this ground loop can be anything from an undesirable
increase in output noise to disruption of power supply and/or load operation. The only way to
avoid ground loops is to ensure that the entire output/load circuit is fully isolated from ground,
and only then establish a single point along the output/load circuit as the single-wire ground
point.
The exact location of the "best" d-c ground point is entirely dependent upon the specific applica-
tion, and its selection requires a combination of analysis, good judgement and some amount of
empirical testing. If there is a choice in selecting either the positive or negative output of the
power supply for the d-c ground point, both sides should be tried, and preference given to the
ground point producing the least noise. For single, isolated loads the d-c ground point is often
best located directly at one of the output terminals of the power supply; when remote error sens-
ing is employed, d-c ground may be established at the point of sense lead attachment. In the
specific case of an internally-grounded load, the d-c ground point is automatically established at
the load.
The output terminals of HSM power supplies are d-c isolated ("floating") from the chassis in
order to permit the user maximum flexibility in selecting the best single point ground location.
Output ripple specifications as measured at the output are equally valid for either side grounded.
Care must be taken in measuring the ripple and noise at the power supply: measuring devices
which are a-c line operated can often introduce additional ripple and noise into the circuit.
There is, unfortunately, no "best" method for interconnecting the load and power supply. Indi-
vidual applications, location and nature of the load require careful analysis in each case.
Grounding a single point in the output circuit can be of great importance. It is hoped that the
preceding paragraphs will be of some assistance in most cases. For help in special applications
or difficult problems, consult directly with Kepco's Application Engineering Department.
2.7.4 POWER SUPPLY/LOAD INTERFACE
The general function of a voltage- or current-stabilized power supply is to deliver the rated out-
put quantities to the connected load. The load may have any conceivable characteristic: it may

2-6 HSMSERIES OPR 052912
be fixed or variable, it may have predominantly resistive, capacitive or inductive parameters; it
may be located very close to the power supply output terminals or it may be a considerable dis-
tance away. The perfect interface between a power supply and its load would mean that the
specified performance at the output terminals would be transferred without impairment to any
load, regardless of electrical characteristics or proximity to each other.
The stabilized d-c power supply is definitely not an ideal voltage or current source, and practical
interfaces definitely fall short of the ideal. All voltage-stabilized power supplies have a finite
source impedance which increases with frequency, and all current-stabilized power supplies
have a finite shunt impedance which decreases with frequency. The method of interface
between the power supply output and the load must, therefore, take into account not only size
with regard to minimum voltage drop, but configuration with regard to minimizing the impedance
introduced by practical interconnection techniques (wire, bus bars, etc.). The series inductance
of the load wire must be as small as possible as compared to the source inductance of the
power supply: error sensing cannot compensate for reactive effects due to this. These dynamic
conditions are especially important if the load is constantly modulated or step-programmed, or
has primarily reactive characteristics, or where the dynamic output response of the power sup-
ply is critical to load performance.
2.7.5 LOAD CONNECTION - GENERAL
Load connections to the HSM power supply are achieved via the bus bars protruding from the
rear panel. The bus bars are each provided with two holes, one 0.34" diameter clearance hole
(for 5/16" UNC threaded fastener) and one #10-32 threaded hole (see Figure 1-3). The threaded
hole is provided for attachment of error sensing leads from the signal connector when local
sense mode is desired.
Load cable or bus bar attachment should use the clearance hole, using a 5/16" UNC nut, bolt
and lockwasher. The use of the proper fastener size and inclusion of a lockwasher are critical to
maintaining intimate contact between the load conductor and output bus bar; Kepco recom-
mends the use of fasteners made of conductive material (brass, phosphor bronze, etc.) to
enhance conductivity; for high current loads (>100A) Kepco recommends the use of Bellville-
style constant tension washers in place of conventional lockwashers.
NOTE
REGARDLESS OF OUTPUT CONFIGURATION, OUTPUT SENSE LINES
MUST BE CONNECTED FOR OPERATION. OBSERVE POLARITIES: THE
NEGATIVE SENSING WIRE MUST BE CONNECTED TO THE NEGATIVE
LOAD WIRE, AND THE POSITIVE SENSING WIRE TO THE POSITIVE
LOAD WIRE.

HSMSERIES OPR 052912 2-7
2.7.5.1 LOAD CONNECTION - METHOD I (LOCAL ERROR SENSING)
The most basic power supply/load interface is a 2-wire connection between the power supply
output terminals and the load. This connection method employs local error sensing which con-
sists of connecting the error sense leads directly to the power supply's output terminals. Its
main virtue is simplicity: since voltage regulation is maintained at the power supply output, the
regulation loop is essentially unaffected by the impedances presented by the load interconnec-
tion scheme. The main disadvantage is that it cannot compensate for losses introduced by the
interconnection scheme and, therefore, regulation degrades directly as a function of distance
and load current. The main applications for this method are for powering primarily resistive and
relatively constant loads located close to the power supply, or for loads requiring stabilized cur-
rent exclusively. The load leads should be tightly twisted to reduce pick-up. See Figure 2-3.
FIGURE 2-3. LOAD CONNECTION - METHOD I (LOCAL ERROR SENSING)

2-8 HSMSERIES OPR 052912
2.7.5.2 LOAD CONNECTION - METHOD II (REMOTE ERROR SENSING)
If the load is located at a distance from the power supply terminals, or if reactive and/or modu-
lated loads are present, remote error sensing should be used to minimize their effect on the volt-
age stabilization. A twisted shielded pair of wires from the sensing terminals directly to the load
will compensate for voltage drops in the load interconnection scheme (see Specifications for
available headroom based on model); the termination point of the error sensing leads should be
at or as close as practical to the load. For these conditions it is also recommended that some
amount of local decoupling capacitance be placed at the error sense termination point to mini-
mize the risk of unwanted pick-up affecting the remote error sense function. See Figure 2-4.
FIGURE 2-4. LOAD CONNECTION - METHOD II (REMOTE ERROR SENSING)