Hitachi SM 6145 Owner's manual

SM 6145
1000 Technology Drive, Pittsburgh, PA 15219
645 Russell Street, Batesburg, SC 29006
STS USA
Secondary Surge Suppressors
(USSP)
STS USA Part Nos.
N451552-05XX
Installation
Operation
Maintenance

STS USASecondary Surge Suppressors USSP)
Copyright 2019 SM 6145 Rev. 3, March 2019

STS USASecondary Surge Suppressors USSP)
Copyright SM 6145, Rev. 23, March 2019 i
Proprietary Notice
This document and its contents are the property of Hitachi Rail
STS USA, Inc. (formerly known as Union Switch & Signal Inc.,
and hereinafter referred to as "STS USA"). This document is
furnished to you on the following conditions: 1.) That no
proprietary or intellectual property right or interest of STS USA
is given or waived in supplying this document and its contents
to you; and, 2.) That this document and its contents are not to
be used or treated in any manner inconsistent with the rights of
STS USA, or to its detriment, and are not to be copied,
reproduced, disclosed or transferred to others, or improperly
disposed of without the prior written consent of STS USA.
Important Notice
STS USA constantly strives to improve our products and keep our customers apprised
of changes in technology. Following the recommendations contained in the attached
service manual will provide our customers with optimum operational reliability. The data
contained herein purports solely to describe the product, and does not create any
warranties.
Within the scope of the attached manual, it is impossible to take into account every
eventuality that may arise with technical equipment in service. Please consult an STS
USA local sales representative in the event of any irregularities with our product.
STS USA expressly disclaims liability resulting from any improper handling or use of our
equipment, even if these instructions contain no specific indication in this respect. We
strongly recommend that only approved STS USA spare parts are used as
replacements.

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Copyright SM 6145, Rev. 23, March 2019 ii
Revision History
REV. DATE NATURE OF REVISION
1
February, 2012
Initial release
2 April 2012
Revised Table 1-1 for suffixes -0525
and -0527.
3
March 2019
Hitachi Rail STS Branding

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Copyright SM 6145, Rev. 23, March 2019 iii
Table of Contents
1. INTRODUCTION ...............................................................................................................................1-1
1.1 Description ................................................................................................................................... 1-1
1.2 Specifications............................................................................................................................. 1-2
1.2.1 Physical/Mechanical (Typical Unit) ...............................................................................1-2
1.2.2 Electrical .......................................................................................................................1-2
2. PRINCIPLES OF OPERATION .........................................................................................................2-1
3. INSTALLATION.................................................................................................................................3-1
4. TROUBLESHOOTING AND MAINTENANCE..................................................................................4-1
4.1 Visual Inspection and Troubleshooting Considerations ............................................................ 4-1
4.2 General Current Test ................................................................................................................. 4-2
5. PARTS LIST ......................................................................................................................................5-1
6. RAIL TEAM AND TECHNICAL SUPPORT ......................................................................................6-1
List of Figures
Figure 1-1. Typical USSP Secondary Surge Suppressor .................................................................. 1-1
Figure 1-2. USG-A Lightning Arrestor Schematic Diagram................................................................ 1-3
Figure 3-1. USSP Battery Line, Track Circuit, and AC Line Models Typical Installation ................... 3-2
Figure 4-1. USSP Test Set Up ........................................................................................................... 4-2
Figure 5-1. USSP Assembly Drawing ................................................................................................ 5-3
List of Tables
Table 1-1. USSP Electrical Specifications – All Models.................................................................... 1-4
Table 1-2. USG-A Lightning Arrestor Specifications ......................................................................... 1-5
Table 4-1. USSP Current Test Values .............................................................................................. 4-3
Table 5-1. Common Parts ................................................................................................................. 5-1
Table 5-2. Parts List .......................................................................................................................... 5-2

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1. INTRODUCTION
1.1 Description
STS USA Secondary Surge Suppressors (USSP), assist in the protection of sensitive
electrical/electronic equipment from excessive voltage surges, such as those produced
by lightning strikes. USSP models (basic part number N451552-05XX) are used in
battery line, track circuit and AC power line applications and are rated for specific
equipment operating characteristics. The battery line models are designated either
USSP-10 or -11, the track circuit models USSP-20 or -21, and the AC line USSP-30 or
31.
The USSP basically consists of a two-piece dielectric plastic case (housing and cover)
containing inductors and surge dissipation components and AAR terminals for
connection of equipment wiring and installation of lightning arresters. The internal
components are attached to the underside of the cover and the top side of the cover is
marked to indicate functions and polarities of the terminals and the maximum current
ratings of the unit. Two mounting brackets are fastened to the ends of the case.
Figure 1-1. Typical USSP Secondary Surge Suppressor
All USSP models incorporate a transient voltage surge suppressor (TVSS) The battery
line model uses a unipolar avalanche type diode. The track circuit model uses a back-
to-back or bipolar avalanche type diode. The AC power line uses a Metal Oxide
Varistor. Two coils are also installed in each unit to limit fast rising surge currents.
Schematics of the battery line, track circuit and AC line models are shown in Figure 2.
Though certain USSP models are not equipped with primary stage lightning arresters,
arresters are ultimately used in the complete surge protection system, either mounted
on the USSP or installed elsewhere in the equipment wiring. STS USA low voltage
USG-A lightning arresters (N451552-0101) are installed on the nominal 12VDC battery
line models. This arrester has no polarity concerns and is wired Line-to-Line (from the

STS USASecondary Surge Suppressors USSP)
Copyright SM 6145, Rev. 23, March 2019 1-2
positive terminal to the negative terminal). On track circuit models, this same USG-A
Low Voltage Arrester is wired across the track leads.
High voltage arresters (N451552-0201) are installed between a ground post and each of
the battery or track circuit lead wires. AC line arresters (N1451552-0401) are installed
across the AC power wires on the AC Line USSP models. Refer to Figure 1-2 for the
various arrester/terminal arrangements and to Service Manual 6108 for further
information on the USG-A arresters. Figure 1-2 shows the positions of the various USG-
A arresters on the USSP models.
CAUTION
The USG-A Low Voltage Arrester (N451552-0101) is a
varistor filled gap arrester designed to be used in a Line-to-
Line application. These are NOT to be used in a Line-to-
Ground application. The USG-A High Voltage Arrester
(N451552-0201) is a true air gap arrester and is designed to
be used in Line-to-Ground applications.
1.2 Specifications
1.2.1 Physical/Mechanical (Typical Unit)
Length (including mounting brackets): 8 7/8 inches
Width: 3 ¾ inches
Depth (including terminals): 3 ¾ inches
Weight (with 3 arresters): 2.25 lbs.
Mounting: Two flat brackets, hole centers 7 ½ inches apart, for ¼
inch diameter fasteners.
Temperature Environment: -40° F to +158° F (-40° C to +70° C)
1.2.2 Electrical
For electrical specifications of the USSP models, refer to Table 1-1.

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T5 (GND)
-0201
T2
+
_
+
_
-0101
T4
T3
T1
T2 T4
T1 T3
+
+
__
-0101
-0201
T6 (GND)
USGA PART NO. N451552
USSP-11 (-0501, 0502,
0503, 0504, 0513, 0514,
0515, 0516)
USSP-10 (-0505, 0506,
0507, 0508, 0517,
0518, 0519, 0520)
++
__
T2 T4
T1 T3
USSP-10 (-0509, 0510,
0511, 0512, 0521,
0522, 0523, 0524)
++
__
T5
(GND)
-0201
T2
T1
T4
T3
-0201
T6 (GND)
USSP-21 (-0525)
++
++
__
__
USSP-20 (-0526)
T2
T1
T4
T3
T2 T4
T1 T3
USSP-20 (-0527)
T2
T1
T8
T7
-0401
USSP-30 (-0528)
T2 T8
T1 T7
T9
-0401
-0401
USSP-31 (-0529)
-0101
-0101
US0105.0001.00
Figure 1-2. USG-A Lightning Arrestor Schematic Diagram

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Table 1-1. USSP Electrical Specifications – All Models
Part No.
N451552- USSP Type Maximum Circuit
Coil
Inductance
(uH)
Capacitor Secondary Suppression Arrestors
0501 11 Battery Line 18 VDC/3A 150 100 MFD, 25 V 18.8 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0502 11 Battery Line 18 VDC/7A 22 100 MFD, 25 V 18.8 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0503 11 Battery Line 18 VDC/15A 16 100 MFD, 25 V 18.8 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0504 11 Battery Line 18 VDC/25A 5 100 MFD, 25 V 18.8 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0505
10
Battery Line
18 VDC/3A
150
100 MFD, 25 V
18.8 V Zener Transient Suppressor
Low Voltage (1)
0506
10
Battery Line
18 VDC/7A
22
100 MFD, 25 V
18.8 V Zener Transient Suppressor
Low Voltage (1)
0507
10
Battery Line
18 VDC/15A
16
100 MFD, 25 V
18.8 V Zener Transient Suppressor
Low Voltage (1)
0508
10
Battery Line
18 VDC/25A
5
100 MFD, 25 V
18.8 V Zener Transient Suppressor
Low Voltage (1)
0509
10
Battery Line
18 VDC/3A
150
100 MFD, 25 V
18.8 V Zener Transient Suppressor
None
0510
10
Battery Line
18 VDC/7A
22
100 MFD, 25 V
18.8 V Zener Transient Suppressor
None
0511
10
Battery Line
18 VDC/15A
16
100 MFD, 25 V
18.8 V Zener Transient Suppressor
None
0512
10
Battery Line
18 VDC/25A
5
100 MFD, 25 V
18.8 V Zener Transient Suppressor
None
0513 11 Battery Line 32 VDC/3A 150 100 MFD, 50 V 33.3 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0514 11 Battery Line 32 VDC/7A 22 100 MFD, 50 V 33.3 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0515 11 Battery Line 32 VDC/15A 16 100 MFD, 50 V 33.3 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0516 11 Battery Line 32 VDC/25A 5 100 MFD, 50 V 33.3 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0517
10
Battery Line
32 VDC/3A
150
100 MFD, 50 V
33.3 V Zener Transient Suppressor
Low Voltage (1)
0518
10
Battery Line
32 VDC/7A
22
100 MFD, 50 V
33.3 V Zener Transient Suppressor
Low Voltage (1)
0519
10
Battery Line
32 VDC/15A
16
100 MFD, 50 V
33.3 V Zener Transient Suppressor
Low Voltage (1)
0520
10
Battery Line
32 VDC/25A
150
100 MFD, 50 V
33.3 V Zener Transient Suppressor
Low Voltage (1)
0521
10
Battery Line
32 VDC/3A
22
100 MFD, 50 V
33.3 V Zener Transient Suppressor
None
0522
10
Battery Line
32 VDC/7A
16
100 MFD, 50 V
33.3 V Zener Transient Suppressor
None
0523
10
Battery Line
32 VDC/15A
5
100 MFD, 50 V
33.3 V Zener Transient Suppressor
None
0524
10
Battery Line
32 VDC/25A
5
100 MFD, 50 V
33.3 V Zener Transient Suppressor
None
0525 21 Track Circuit 17 VAC, 7 VDC/50A 5 None 8 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0526
20
Track Circuit
17 VAC, 7 VDC/50A
5
None
31.6 V Zener Transient Suppressor
Low Voltage (1)
0527
20
Track Circuit
17 VAC, 7 VDC/50A
5
None
8 V Zener Transient Suppressor
None
0528
30
AC Power
120 VAC/20A
8
None
140 VAC Zener Transient Suppressor
Line (1)

STS USASecondary Surge Suppressors USSP)
Copyright SM 6145, Rev. 23, March 2019 1-5
Part No.
N451552- USSP Type Maximum Circuit
Coil
Inductance
(uH)
Capacitor Secondary Suppression Arrestors
0529
31
AC Power
240 VAC/20A
8
None
275 VAC Zener Transient Suppressor
Line (2)
0532 21 Track Circuit 63 VDC/50A 5 None 63.2 V Zener Transient Suppressor
Low Voltage (1)
High Voltage (2)
0535
20
Track Circuit
44 VDC/50A
4
None
44 V Zener Transient Suppressor
None
Table 1-2. USG-A Lightning Arrestor Specifications
Part No.
N4551552-
Operating
Voltage
Firing
Voltage Resistance
-0101 32 VDC, 25 VAC
75-200 VDC
50-150 VAC (60 Hz)
103ohms @ 32 VDC
-0201 250 VDC, 175 VAC
500-1300 VDC
350-950 VAC (60 Hz)
109ohms @ 100 VDC
-0401
140 VAC
NA
5 x 103ohms @ 120 VAC

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Copyright SM 6145, Rev. 23, March 2019 2-1
2. PRINCIPLES OF OPERATION
The principal function of the USSP is to suppress the small "overshoot" voltages that
escape the primary arresters. These voltages are potentially destructive to sensitive
components such as transistors. When a high surge voltage is impressed on equipment
lines (power or signal transmission), the primary Line-to-Ground arresters shunt the
surge to ground while the primary Line-to-Line arrestors hold the Line-to-Line voltage to
reasonable levels. However, in the presence of surges with fast rise times (measured in
thousands of volts or amperes per microsecond), the time required to achieve complete
breakdown of the primary arresters (if used alone) is sufficient to allow some overshoot
voltage into the equipment lines.
USSP models use a Zener/TVSS diode or varistor as transient voltage suppressors to
shunt this residual surge voltage before it can reach equipment components. The surge
current first passes through the inductor coils, which limit or "choke" the current to a
level which will not destroy the Zener/TVSS diode. The coils also assist in the firing of
the arrester. When the surge voltage reaches the reverse-bias Zener/TVSS value, the
Zener/TVSS limits the surge voltage.
USSP track circuit models use back-to-back Zener/TVSS devices to shunt overshoot
voltages in both low voltage AC and DC track circuits. The AC line models use a Metal
Oxide Varistor to limit the surge voltages equally in both polarities.
The high voltage arresters are always wired in a Line-to-Ground configuration to shunt
the surge energy to an intentional ground path rather than through the equipment to an
unintentional ground.

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3. INSTALLATION
The USSP may be installed in any location convenient for connection of equipment and
grounding wiring. However, the following restrictions and precautions should be
observed to ensure that the USSP will function properly.
WARNING
Make certain that equipment operating and/or signal current
in the vicinity of the USSP is turned off before beginning any
installation work, otherwise personal' injury may result.
•If possible avoid installing the unit in any area where it may be subjected to moisture,
dirt, corrosive agents or extremes of temperature (outside of that specified).
•Make certain to use mechanical fasteners that will keep the unit securely mounted,
especially in high-vibration areas on the wayside. Avoid installing the unit upside
down.
•Make certain that electrical connections to the terminal posts (including leads on lightning
arresters installed in the field) are also tight. Use only eyelet terminals (crimped and
soldered) on wiring to be attached to the USSP, and keep the wiring orderly and away
from the lightning arrester bodies.
CAUTION
If USSP models without lightning arresters (USSP part
number suffix 0509, 0510, 0511, 0512, 0522, 0523 and
0524) are to be used, they must be used in conjunction with
primary arresters in the final installation. Otherwise, damage
will result to both the USSP and other equipment when a heavy
surge current is impressed on equipment lines. Also, only STS
USA USG-A arresters should be attached to the USSP (per
STS USA specification). Use of any other arrester may lead to
equipment damage.
Consult STS USA Engineering for USSP installations in systems already equipped with
lightning arresters. Figure 3-1 is a schematic of the three basic USSP models (battery,
track circuit, AC line) in a composite installation. For other, special installations, consult
STS USA engineering.

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US0105.0002.00
1 2
56
34
USSP-21
SOLID STATE
EQUIPMENT
USSP-11
34
56
12
RECTIFIER
USSP-30
7 8
12
120
VAC
USG-A
HIGH VOLTAGE
ARRESTERS
Figure 3-1. USSP Battery Line, Track Circuit, and AC Line Models
Typical Installation

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Copyright SM 6145, Rev. 23, March 2019 4-1
4. TROUBLESHOOTING AND MAINTENANCE
WARNING
Make certain that equipment operating and/or signal
current going through the USSP is turned off, before starting
any hands-on maintenance, otherwise personal injury may
result.
4.1 Visual Inspection and Troubleshooting Considerations
A USSP unit which fails to provide adequate surge protection, or is apparently causing
equipment operating problems, should be removed from its installation and the cover
removed to make the following examinations:
1. Check for cracks or other damage to the case or cover.
2. Check the tightness and cleanliness of the AAR terminals on the cover, and the
tightness of all nuts securing the external wiring terminals and the lightning arresters.
3. Check the external wires and terminals and the internal components leads and
terminals for breaks, looseness, fraying or loss of insulation.
4. Check the outward appearances of the components, particularly the capacitor and/or
solid state component(s). If these have been subjected to full surge currents, there may
be discoloration, evidence of burning or destruction of the component body.
For maintenance information on the USG-A Lightning Arresters, see SM6108. If the
above examination turned up outward physical/mechanical defects, these may be
corrected and the unit put back into service, however the defect may not have been the
cause of the original failure. If the examination turns up no obvious defects, STS USA
recommends that the unit be removed from service and replaced with a new unit.
However, the unit may also be given a general current test; this test is described in
Section 4.1. The test equipment only simulates normal equipment operating voltages,
not surge voltages. If the test suggests a faulty component, the individual component
may be checked for continuity, operating values, etc. and replaced if necessary.
CAUTION
Make certain to observe proper polarities (where applicable)
when testing or replacing the solid state voltage suppression
components, otherwise these may be damaged when power
is applied.

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Copyright SM 6145, Rev. 23, March 2019 4-2
4.2 General Current Test
The general current test requires assembly of a test rig consisting of a power supply or
Variac (for AC voltage control), a high impedance voltmeter, a 100 ohm/10 watt resistor
and an ammeter calibrated to read in milliamperes. The test rig is assembled as shown
in Figure 4-1. The test may be conducted with the cover on or off the case.
US0105.0003.00
POWER
SUPPLY
OR
VARIAC
AMMETER
100 OHM/10 WATT
RESISTOR
A
V
HIGH IMPEDANCE
VOLTMETER
TERMINAL
2
TERMINAL
1
USSP
Figure 4-1. USSP Test Set Up
Use Table 4-1 to select the proper input voltage for the particular USSP model being
tested. Apply this voltage to terminals 1 and 2.
NOTE
If applied voltage is DC, apply "Plus" to terminal 2 and
"Minus" to terminal 1.
For the selected voltage setting (corresponding to the "Maximum Circuit" rating of the
unit), the ammeter should show a current equal to or less than that indicated in column
3 of Table 4-1. If the ammeter indicates a higher current, the unit should be replaced.

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Copyright SM 6145, Rev. 23, March 2019 4-3
Table 4-1. USSP Current Test Values
Part Number
N451552-
Applied Voltage Max. Current
0501
18 VDC
0.010A
0502
18 VDC
0.010A
0503
18 VDC
0.010A
0504
18 VDC
0.010A
0505
18 VDC
0.010A
0506
18 VDC
0.010A
0507
18 VDC
0.010A
0508
18 VDC
0.010A
0509
18 VDC
0.001A
0510
18 VDC
0.001A
0511
18 VDC
0.001A
0512
18 VDC
0.001A
0513
32 VDC
0.033A
0514
32 VDC
0.033A
0515
32 VDC
0.033A
0516
32 VDC
0.033A
0517
32 VDC
0.033A
0518
32 VDC
0.033A
0519
32 VDC
0.033A
0520
32 VDC
0.033A
0521
32 VDC
0.001A
0522
32 VDC
0.001A
0523
32 VDC
0.001A
0524
32 VDC
0.001A
0525
7 VDC
0.005A
0526
7 VDC
0.005A
0527
7 VDC
0.001A
0528
120 VDC
0.030A
0529
120 VDC
0.030A
0532
63 VDC
--
0535
44 VDC
--

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