1993 Specifications
CSJ 0100-13-019, etc.
SPECIAL SPECIFICATION
8915
Uninterruptible Power Supply (UPS)
1.
Description. This Item sets forth the minimum requirements for a shelf or rack mounted
Uninterruptible Power Supply (UPS) for use with Light Emitting Diodes (LED) Traffic
Signal Modules. The UPS assembly shall include, but not be limited to, inverter/charger,
power transfer relays, batteries, wiring, battery ground box and all necessary hardware. The
UPS shall provide reliable emergency power to a traffic signal system (vehicle and
pedestrian) in the event of power failure or interruption. The UPS shall also act as a power
conditioner.
(1) The UPS shall be capable of providing power for full run-time or flashing operation for
an “LED only” intersection (all colors and pedestrian heads).
(2) The UPS shall be designed for outdoor applications in accordance with NEMA TS2
1998 Section 2.
2.
Operation.
(1) The UPS shall provide as a minimum two (2) hours of full run time operation or four
(4) hours of flash operation. For an intersection that requires 700 watts or less, the UPS
shall be a minimum 700 W/1000 VA active output capacity, with 80% minimum
inverter efficiency. For an intersection that requires 700 watts or greater, the UPS shall
be a minimum 1400 W/1800 VA active output capacity, with 80% minimum inverter
efficiency.
(2) The transfer time allowed, from disruption of normal utility line voltage to stabilized
inverter line voltage from batteries, shall be less than 65 milliseconds. The same
allowable transfer time shall also apply when switching from inverter line voltage to
utility line voltage.
(3) Three (3) sets of normally open (NO) and normally closed (NC) single-pole doublethrow dry contact relay closures shall be made available on the front of the UPS panel
and label so as to identify each contact.
(4) The first set of NO/NC contact closures shall be energized whenever the unit switches
to battery power. Contact shall be labeled or marked as “On Batt”.
(5) The second set of contact closures shall be energized whenever the battery approaches
approximately 40% of remaining capacity. Contact shall be labeled or marked as “Low
Batt”.
(6) The third set of contact closures shall be energized two hours after the unit switches to
battery power. Contact closures shall be labeled or marked “Timer”.
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(7) Operating temperature for both the inverter/charger unit and power transfer relay shall
be -29°F to + 165°F.
(8) The power transfer switch shall be rated as a minimum 240 VAC/30 amp.
(9) The UPS shall use a temperature compensated battery charging system. The charging
system shall compensate over a range of 1.4 – 2.2 mV/ °F per cell.
(10) The temperature sensor shall be external to the inverter/charger unit. Unless otherwise
required by the plans the temperature sensor shall come with 8 feet of wire.
(11) Batteries shall not be charged when battery temperature exceeds 122°F ± 5°F.
(12) The UPS shall bypass utility line power whenever the utility line voltage is outside of
100 VAC to 130 VAC (± 2 VAC).
(13) When battery power is used, the UPS output voltage shall be between 110 VAC and
125 VAC, pure sine wave output, ≤ 3% THD, 60 Hz ± 3 Hz.
(14) When the utility line power has been restored at above 105 VAC ± 2 VAC or below 125
VAC ± 2 VAC for more than 30 seconds, the UPS shall transfer from battery backup
inverter mode back to utility line mode. The UPS shall be equipped to prevent a
malfunction feedback to the cabinet or from feeding back to the utility service.
(15) In the event of inverter/charger failure, battery failure or complete battery discharge, the
power transfer shall revert to the NC (de-energized) state, where utility line power is
connected to the cabinet.
(16) Recharge time for the batteries to 80% or more of full battery charge capacity shall not
exceed 20 hours.
(17) The UPS shall be compatible with TS1, TS2 and Model 2070 controllers and cabinet
components for full time operation.
3.
Mounting and External Battery Ground Box.
(1) The UPS shall be shelf mounted in a TS1 and TS2 cabinets. For Model 2070 332
cabinet shall be rack mounted. The power transfer switch shall be able to be mounted on
the shelf or side of cabinets. The interconnect cables shall be no less than 6 feet long of
# 10 AWG wire. Relay contact wiring for each set of NO/NC relay contact closure
terminals shall be no less than 6 feet long of #18 AWG wire.
(2) The power transfer relay shall be capable of accepting No. 6 AWG conductor wire from
the utility power service.
(3) The battery ground box shall be Armorcast Model number A6001640TA4TXDT or
equivalent, approved by TxDOT Traffic Signal Engineer. The battery cable leads
connecting the batteries to the inverter/charger shall be at least 8 feet or longer as
specified in plans. Battery cables provided to connect battery to battery shall be long
enough to accommodate the battery covers provided with the battery ground box.
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4.
Displays, Controls, Diagnostics and Maintenance.
(1) The UPS shall include a display and/or meter to indicate current battery charge status
and conditions. The UPS shall include a front panel event counter display to indicate the
number of times the UPS was activated and front panel hour meter to display the total
number of hours the unit has operated on battery power. Both meters shall be resettable.
(2) The UPS shall have lightning surge protection compliant with IEEE/ANSI C.62.41.
(3) The UPS shall be equipped with an integral system to prevent battery from destructive
discharge and/or overcharge.
(4) The UPS and batteries shall be easily replaced with all needed hardware and shall not
require any special tools for installation.
5.
Battery System.
(1) Individual batteries shall be 12 V type, 65 amp-hour maximum, and shall be easily
replaced and commercially available off the shelf.
(2) Batteries shall consist of 4 to 8 (if specified in plans) with a cumulative minimum rated
capacity of 240 amp hours.
(3) Batteries shall be deep cycle, sealed prismatic lead-calcium based AGM/VRLA
(Absorbed Glass Mat/Valve Regulated Lead Acid).
(4) Batteries shall be certified by the manufacturer to operate over a temperature range of 13°F to +165°F.
(5) Batteries shall indicate maximum recharge data and recharging cycles.
(6) Battery interconnect wiring shall via modular harness with red and black cabling that
terminates into a typical power pole style connector. Harness shall be equipped with
mating power pole style connectors for batteries and a single insulated plug-in style
connection to inverter/charging unit. Harness shall allow batteries to be quickly and
easily connected in any order and shall be keyed to ensure proper polarity and circuit
configuration.
(7) Insulated cover shall be provided as to prevent accidental shorting.
6.
Documentation.
(1) Operation and maintenance manuals shall be provided.
(2) Independent lab reports verifying that UPS system meet or exceed specifications.
(3) Board level schematics shall be provided.
7.
Testing. TxDOT reserves the right to do testing on UPS systems to ensure Quality
Assurance on unit before installations and random sampling of units being provided to the
State. UPS systems that fail will be taken off of the Qualified Products List (QPL).
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8.
Warranty. The manufacturer shall provide as a minimum for the UPS, a two-year warranty
from date of acceptance. Batteries shall be warranted for full replacement for two-years
from the date of acceptance.
9.
Measurement. This Item will be measured as each Uninterruptible Power Supply unit
furnished. Installed, made fully operational, and tested in accordance with these
specifications.
10. Payment. The work performed and materials furnished in accordance with this Item and
measured as provided under “Measurement” will be paid for at the unit price bid for
“Uninterruptible Power Supply”. This price shall include all equipment described under this
Item with all cables and connectors, all documentation and testing; and shall also include the
cost of furnishing all labor, materials, training, and equipment necessary to complete the
work.
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