Specifications

2.2. POWER SUPPLY
Figure 2.2: Existing system: close-up of the gate
showing the Texas Instruments Series 2000 “small” loop antenna and the
two infra-red beam detectors.
2.2 Power Supply
The unit is powered from the 230V AC mains generator which is located
on the island. Battery backup is in the form of a commercial 230V AC
Uninterruptable Power Supply (UPS) which is housed in a separate enclosure
from the RFID reader due to its size.
The following problems have been identified:
• This system is highly inefficient as mains power is stepped down and
stored in a battery. During a power failure, this voltage is stepped back
up to 230V AC and then back down to 12V DC again. These processes
are all lossy which has the end result of a very short backup period (in
the order of a few hours).
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