ADT 4520-810 Power Supply Unit
Unimode® System Fire Alarm Monitor & Control
U.L. Listed
Unit Description
The 4520-810 Power Supply Unit is a self-contained, self-monitoring rectifier/charger designed for mounting in larger (15- and 30-module capacity) UNIMODE cabinets. The unit operates on 120-volt, 60 Hz single-phase AC and supplies three outputs to the UNIMODE System:
- 24/12 volts DC, 0.850 amperes (regulated) - for internal and external circuits requiring regulated voltage.
- 28.2 volts DC, 0.5 amperes (regulated) - for charging sealed lead-acid backup Battery Pack.
- 24 volts DC, 10 amperes (unregulated) - for signaling devices.
Four fuses, accessible from the front of the unit, protect the AC, battery, and 24 and 12 VDC (regulated) circuits.
Unit Features
- Low power dissipation in Normal Mode.
- Self-supervised for AC power interruption, blown fuses, battery charge and loose, disconnected or reversed battery leads.
- Optional low battery supervision, which replaces most self-supervisory features except for supervision of the 12 and 24 volt fuses.
- Low battery disconnect available with either the self-supervised or the low battery supervision option.
- Integral charge for sealed lead-acid backup Battery Pack.
UNIT DESCRIPTION
The 4520-810 Power Supply Unit supplies regulated 24/12 volts DC (for circuitry), regulated 28.2 volts DC (to float the sealed lead-acid backup Battery Pack), and unregulated 24 volts DC, rated at 10 amperes, full load (for the signal circuits). Four fuses are for AC (5A, slow blo), battery (15A), 12 VDC regulated (1A), and 24 VDC regulated (1A). A terminal strip permits measuring battery float voltage and trickle charge current, and eases connection to the regulated and unregulated outputs, AC input, and system ground. A wire harness plugs the Power Supply Unit into the Common Control Unit, and two wires connect to the sealed lead-acid backup Battery Pack.
OPERATION
Interruption of AC power automatically switches the standby batteries into the UNIMODE System. At the Common Control Unit, the green AC POWER ON lamp is extinguished, and a system trouble is initiated (amber COMMON TROUBLE lamp and audible sounder pulse). Restoration of AC power automatically switches AC into the system, returning UNIMODE to Normal Mode, and the standby battery pack goes on charge. The Power Supply Unit is also self-monitoring on blown fuses and loose or disconnected battery leads (unless low battery-voltage supervision option is included), any of which annunciates a system trouble at the Common Control Unit.
[Image description: A rear view of the ADT 4520-810 Power Supply Unit showing various terminals, fuses (F1-F4), and connection points labeled for AC input, battery, ground, and signaling devices. It includes a caution for high voltage and labels for fuse ratings and types.]
Features
- Furnishes up to 850 mA regulated power for system operation and up to 10A for powering connected signaling devices.
- Provides charging current for battery pack.
- Self-monitoring on AC power interruption, blown fuses, reversed or disconnected battery leads, and battery charging current.
- Optional supervision of low battery voltage and load disconnect on low voltage (in place of AC, battery lead, and battery charging current supervision).
Functional Description
The 4520-810 Power Supply Unit operates on 120 VAC, 60 Hz, single-phase power and provides regulated 12 and 24 VDC, 850 mA for system solid state circuitry and accessories requiring regulated voltage; regulated 28.2 VDC, 0.5A for float charging the standby battery pack; and unregulated 24 VDC, 10A for the signaling devices. The wire harness that plugs into the mating plug on the 4520-Type Common Control Unit printed circuit board carries regulated +12 V and +24 V and circuit ground for powering UNIMODE circuitry via the data cable. Two separate leads are connected to the 4520-Type standby Battery Pack. Terminals at the front of the 4520-810 Power Supply Unit make available the unregulated 24 VDC, 10A for connection to field terminals on 4520-Type Alarm Receiving and Signal Control modules for powering the connected signaling devices. In addition, regulated +12 VDC and +24 VDC and circuit ground are available for accessories requiring regulated voltage. Total current, including current drawn by system circuitry, must not exceed 850 mA.
Power Supply Specifications
Table I lists the power supply specifications:
| Input Power | Output Voltage | Current (max) |
|---|---|---|
| 110-120 VAC, 50/60 Hz | +12 VDC regulated | 850 mA (total for both) |
| +24 VDC, regulated | ||
| +24 VDC, unregulated | 10A | |
| Charging Voltage | Charging Current | |
| 28.2 VDC | 3-30 mA (3A, max) |
Installation
The 4520-810 Power Supply Unit is self-monitoring on blown fuses and other critical power conditions, and initiates a system trouble should any such condition occur. A system trouble is annunciated visually and audibly at the 4520-Type Common Control Unit (amber TROUBLE COMM. lamp and integral trouble sounder pulse until the trouble is corrected).
The 4520-810 Power Supply Unit needs no conditioning to provide supervision of AC power loss, reversed or disconnected battery leads, or battery charging current below 3 mA. (AC power loss is accompanied by extinguishment of the green AC power lamp on the 4520-Type Common Control Unit, in addition to the system trouble indications.) If the power supply is conditioned to supervise the voltage of the standby batteries, however, the standard supervision features (except blown fuses) are disabled.
Supervision Features
Table II outlines the supervision features and corresponding jumpers:
| Supervision Features | Jumpers/Plugs to be Open-Circuited |
|---|---|
| AC power loss, loose/disconnected battery lead, battery charging current below 3 mA, blown fuse. | NONE |
| Low battery voltage (20.4 VDC), blown fuse. | B |
| Load disconnect (may be enabled with either above arrangement). | D |
Field Wiring Connections
Refer to field wiring diagram (Figure 2) for details. Installation of the 4520-810 Power Supply Unit in the UNIMODE cabinet is outlined in the Installation Section of this bulletin.
Note: On installation, connect standby batteries first; then connect AC power. When disconnecting power, such as during fuse replacement, disconnect AC power first then disconnect batteries.
Power Supply Test
The following procedure is part of a system inspection that must be made after initial installation, and thereafter to determine proper functioning of the unit. The unit must be installed in the cabinet and the system completely wired.
Caution: Disconnect or disable 4520-Type Municipal Tie, Remote Station Connection, Multiple Auxiliary Relay, Halon-Release Control, and other critical function modules BEFORE proceeding with unit test. Refer to associated Technical Data Sheets for details on isolating any such module included.
Using a Type 3932 Meter, check that the voltage and current readings fall within the ranges specified. Replace power supply unit if values are out of range.
Voltage Checks:
| Connect Meter between: | Voltage |
|---|---|
| Terminals 4(+) and 6(-) | 23 to 25 V |
| Terminals 5(+) and 6(-) | 11 to 13 V |
| Terminals 9(+) and 8(-) | 23 to 28 V |
| Terminals 2(+) and 3(-) | 28.2 V |
Remove strap joining power supply Terminals 1 and 2 after meter is connected.
Charging Current Check:
| Connect meter between: | Charging Current |
|---|---|
| Terminals 1(+) and 2(-) | 3 to 30 mA (3A, max) |
REMINDER: Restore all critical function modules to normal after test is completed.
Replacement Parts
Fuses
- Fuse, 5A, slo blo, Littelfuse 313005 (for AC) (SCN 828817)
- Fuse, 1A, Littelfuse 312001 or equivalent (for 24 VDC, regulated) (SCN 828803)
- Fuse, 1A, Littelfuse 312001 or equivalent (for 12 VDC, regulated) (SCN 828803)
- Fuse, 15A, Bussman ABC (for battery) (SCN 828890)
Wiring Diagram and Notes
[Image description: A detailed wiring diagram illustrating the connections for the ADT 4520-810 Power Supply Unit. It shows connections to supplementary equipment, signaling devices, battery pack, and the Common Control Unit. The diagram includes labels for fuses, terminals, voltage outputs, and notes regarding measurements, supervision modes, and battery types. Specific notes detail how to measure float voltage and charging current, and mention different standby battery options (4520-605, 4520-608, 4520-615). It also includes cautions about power disconnection and fuse replacement, and references to other technical data sheets and diagrams.]
