T H E C O N T I N U O U S P O W E R C O M P A N Y
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1.2 OPERATING
MODES
Clary’s SP Series Uninterruptible Power Systems (UPS) are designed for powering traffic &
pedestrian indications, plus critical traffic control devices (i.e., controllers, modems, CMU’s,
etc.). The power system consists of three elements, which work together to provide critical
loads with continuous, conditioned, regulated, sinusoidal waveform power that is free from
disturbances such as spikes, surges, brownouts or blackouts. These elements are the:
1. UPS Module – (UPS)
2. Power Interface Module - (PIM)
3. Battery
Module
Power loads in the traffic intersection (e.g. LED signals) receive standby backup power
through a highly reliable contactor housed in the PIM. Backup power is achieved with a set
of rechargeable, SVRLA (sealed valve-regulated lead-acid), maintenance-free, AGM
(absorbed glass mat), batteries. The complete UPS system is controlled by an onboard
digital microprocessor at all times.
There are two basic modes of operation:
•
Standby
Operating Mode
•
Continuous
Operating Mode
In both modes, the UPS continuously generates 120V AC power. The selected mode
determines when and how the UPS generated power is applied to the loads in the traffic
cabinet.
Standby Operating Mode:
During
Standby
operation, utility (AC) power enters the PIM and passes through a normally
closed, contactor then directly out to the cabinet power bus, PDA, etc. This utility power is
used to power the intersection until a power disturbance occurs at which time, the contactor
is switched, routing the UPS generated AC power to the cabinet power bus. Typically, the
UPS will then be drawing its power from the battery pack. This operation continues until
good utility power is restored, after which, the contactors switch back to route the utility
power to the loads.
With
Standby
operation, 0.5 seconds (user programmable from 30ms to 2.5sec) after an
outage is detected, standby power is connected to the system and the Flash Command is
initiated, forcing the cabinet into
Flash
Mode
operation. Depending on the size of the
battery system being used and the loading on the power system, backup power can
continue for several hours.
When utility power returns, (or upon application of generator power) the SP Series UPS
waits 30 seconds to be sure that the utility power has stabilized. After this built-in safety