EQUIPMENT: T1200-C
PUBLICATION: MARINEC-P-A
ISSUE No. & DATE: 3 02/14
© 2014 Thorn Security Ltd PAGE 35 of 67
Registered Company: Thorn Security Ltd. Registered Office: Dunhams Lane Letchworth Garden City Hertfordshire SG6 1BE
14. Power Supplies
14.1 General
The T1200 range includes 4 types of power supply.
Refer to the table in section 4.1.1 for a list of the
various panel/PSU combinations.
All PSUs include:
• Temperature compensated battery charging and
fault monitoring facilities for 2x 12V Sealed
Lead-Acid standby batteries.
• Automatic “battery connected” check. If a battery
disconnection is detected, the Battery/Charge
Fault is indicated, illuminating the Batt/Charge
fault LED and activating the “common fault”
signal to the panel microcontroller.
• Automatic periodic battery load test. If the
battery and interconnection resistance is greater
than allowed, the Battery/Charge Fault is
indicated, illuminating the Batt/Charge fault LED
and activating the “common fault” signal to the
panel microcontroller.
• Automatic “battery disconnect” facility. This
electronically disconnects the battery when the
battery terminal voltage falls below
approximately 21V, thus preventing deep
discharge of the batteries if the panel is powered
for longer than the specified standby period.
Also operates to protect the PSU if a short circuit
occurs across the battery terminals.
• All PSUs are approved to EN54-4.
• All panels, except repeaters, have total power
supply failure indication. An internally mounted
[non-rechargeable] 9V battery (PP3 cell)
provides the power to operate the panel buzzer
for at least 1 hour following the loss of both the
mains and stand-by supplies.
14.2 T1204A1 110V AC and T1204A2
230V AC mains powered PSUs.
The control and monitoring circuitry for the 1.5 Amp
110Vac and 230Vac mains powered PSUs is built
onto the C1626 motherboard. The transformer is
located on the chassis under the motherboard. See
Figure 4 – T1204 Panel – General Assembly.
14.2.1 Supply Input
The Mains input is 230Vac @ 50/60Hz for the
T1204A2 or 110Vac @ 50/60Hz for the T1204A1.
14.2.2 Supply Output
The DC output is 27.3Vdc at 25°C with load up to
1.5A.
The output current is shared between the panel
load and battery charging. The battery charging
current is therefore dependent on output current
and will fall to zero as the panel load approaches
1.7A.
14.2.3 Fusing
The mains supply is protected by a replaceable
3.15A 20mm mains fuse in the mains terminal
block.
The battery circuit is protected by a replaceable 2A
20mm fuse on the C1626 motherboard.
The DC load output is protected by electronic
current limiting circuitry.
14.2.4 Battery Charger
The power supply provides a temperature
compensated charging voltage to the batteries over
a temperature range of –10
o
C to 55
o
C. The
temperature profile of the charging voltage is
compatible with 2x 12V series-connected sealed
lead-acid Power-Sonic batteries (Up to a maximum
capacity of 7Ah).
A Thermistor fitted inside the battery box senses
the battery temperature. The Thermistor circuit is
monitored for both open and short circuit fault
conditions.
The charging voltage may also be adjusted via the
trimmer potentiometer VR1 on the C1626
motherboard. However, the charging voltage is
factory set and adjustment should not be
necessary.
NOTE: The battery charging voltage should be
set in the range 27.2V to 27.4V at a battery
temperature of 20
o
C (use a 4k7 resistor in place
of the Thermistor when setting the voltage).
14.2.5 Battery Monitoring
The health of the batteries, the battery connections
and fuse are checked by a battery monitor circuit
and automatic battery test facility once every 30
seconds. The Batt/Charge fault LED is illuminated
and the ‘Fault Output’ is operated if the Battery is
disconnected, the Battery voltage falls below 15.7V
or the Battery and inter-connection resistance is
greater than or equal to 1Ω. The circuitry also
protects against reversed connection of the
batteries.
14.2.6 Visual Indications
The following visual indications are provided:
i) A green ‘Output – OK’ LED. This simply
indicates that power is being supplied to the
load.
ii) A yellow ‘Thermistor Fault’ LED. This indicates
an open circuit or short circuit fault of the
Thermistor circuit.
iii) A yellow ‘Batt Charge Fault’ LED indicating any
one of the following conditions:
o Battery or associated wiring has become
disconnected.
o Battery or associated wiring has become
short circuited.
o Battery fuse blown.
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