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Product Information Bulletin by qfg42964

VIEWS: 33 PAGES: 3

									     Product Information

     Bulletin
2400 Nelson Miller Parkway Louisville, KY 40223 (502) 244-7400 Fax: (502) 244-7444 www.safetran.com




SUBJECT:                            SSCC III, SSCC IIIA, SSCC III Plus and SSCC IV                    NO:     1-04

CONCERN:                            Operation with Disconnected Power                                 DATE:   07-15-04

CLASS / ACTION                      OPERATIONAL / MANDATORY


I.    BACKGROUND

During recent testing and cut over of a crossing equipped with a Solid State Crossing Controller IV, (SSCC
IV), personnel observed a partial activation of the gates (the lights flashed but the gates stayed up). This
condition occurred when all of the negative power wires to the controller were opened and an
undetermined number of light circuits were open.

                                                                                         NOTE

                                       On a 40A unit, 3 negative wires are expected to be used while
                                       on a 20A unit, 2 negative wires are expected to be used.

Investigation revealed that when all of the negative battery wires were disconnected, the negative buss
inside the SSCC unit floated above true battery negative. Since all of the controller outputs have paths back
to battery negative via their respective loads, complete circuits are possible. Therefore, with the GC+
output(s) referenced to the negative buss inside the unit, the voltage on GC+ floated above battery
negative sufficiently to keep the gate control energized.

While the situation occurred with an SSCC IV, the output circuitry of the SSCC III, SSCC IIIA, SSCC III Plus
and the SSCC IV crossing controllers is similar. Therefore, the SSCC III, SSCC IIIA, SSCC III Plus and SSCC IV
are of equal concern.

Under certain reduced lamp load conditions, this leakage can keep the hold clear mechanism and gate
control relay energized. During subsequent tests with the crossing flagged, upon activation of the controller
by a train move the lights flashed as intended but the gates remained vertical.




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Document No.: PIB 1-04                 Version: A
                                                               Firm of assessed capability ISO9001
II. SOLUTION

Safetran will provide a two-part solution to this problem:
           Safetran will furnish an updated warning label for existing units.
           Only controllers with gate controls isolated from the internal negative buss will be furnished in
           the future.

•   Updated Warning Label

The current warning label on SSCC units reads as follows:

                                                  WARNING

                                       REMOVING INPUT POWER FROM THE
                                      SSCC WILL CAUSE THE GATES TO DROP
                                      BUT THE LIGHTS WILL NOT ACTIVATE.

The updated warning label, to be located directly under the B and N connector, will read as follows:

                                                  WARNING

                                        IF B OR N ARE FULLY OR PARTIALLY
                                      REMOVED, SIGNALS AND/OR GATES MAY
                                            NOT OPERATE AS INTENDED.
                                        TAKE ALTERNATE MEANS TO WARN
                                       VEHICULAR TRAFFIC AND EMPLOYEES.

In addition, appropriate revisions have been made in the SSCC IIIA (SIG-00-02-12), SSCC III Plus (SIG-00-02-
03) and SSCC IV (SIG-00-03-02) manuals that describe the situation in more detail and restate the warnings.

Contact Safetran’s California Division Customer Service Department at 909 987-4673 or 800 793-7233, or
your Safetran sales representative to obtain the updated warning labels.

•   Future Equipment

In the past, Safetran had SSCC IIIA, SSCC III Plus and SSCC IV models with and without isolated gate control
outputs. Now, all SSCC IIIA, SSCC III Plus and SSCC IV units will have the gate control outputs isolated from
the internal negative buss. The isolated gate control provides a two-wire circuit to the motor control relay
and hold-clear mechanism within the gate.

Those models without the isolated gate control outputs will be converted to isolated output. Appropriate
changes will be made on the SSCC faceplates of future production units to indicate that they have isolated
outputs. The part numbers for the majority of units will not change.


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Document No.: PIB 1-04   Version: A
If a common return gate circuit connected to N is required in the gate, a single wire connecting GC- and
negative battery must be installed. To provide additional guidance, isolated gate control units will have an
additional warning label near the gate control outputs that states:

                                                  WARNING

                                         DO NOT JUMPER 1GC- (2GC-)
                                      DIRECTLY TO N ON CONNECTOR J2

The 1GC- and 2GC- should be connected to the N wire on the surge protection for the gate cables.
Connecting the 1GC- or 2GC- directly to the N terminal on connector J2 would inadvertently connect the
negative gate control back to the internal battery buss, which should be prevented.

All units returned to Safetran for repair will have the appropriate labels affixed.

Following is a brief overview of the affected units

SSCC IIIA
Current 91160/91165 units                                Current 91180/91185 units
Future units will have isolated gate control outputs and Discontinued
existing units will receive updated labels


SSCC III Plus
Current 91190/91195 units                                Current 91200/91205 units
Future units will have isolated gate control outputs and Discontinued
existing units will receive updated labels


SSCC IV
Current 91210/91215 units                                Current 91220/91225 units
Future units will have isolated gate control outputs and Discontinued
existing units will receive updated labels

If there are any questions concerning the contents of this bulletin, please contact your Safetran sales
representative or the California Division Customer Service Department at 909 987-4673 or 800 793-7233.




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Document No.: PIB 1-04   Version: A

								
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