A presentation at What Is the Von Duprin Power Supply? Models, Uses and How to Choose in in Monroe County, NY, USA by american locksets
What Is the Von Duprin Power Supply? Models, Uses and How to Choose What Is the Von Duprin Power Supply? If you are specifying or installing electrified exit hardware in a commercial building, the Von Duprin power supply is one of the components you will need to source and connect correctly before the system will work. It is not part of the exit device itself. It is a separate, wall-mounted or ceiling-mounted unit that converts standard 120 or 240 volt AC building power into the low-voltage regulated DC output that Von Duprin electrified panic devices, electric strikes, and electrified door hardware require to operate. Without a compatible power supply, an electrified Von Duprin exit device has no power source and will not function electronically. The mechanical push-bar egress works at all times, but the electric latch retraction, quiet latch retraction, and access control integration features all depend on a correctly specified power supply delivering the right voltage and current. This guide explains what the Von Duprin power supply is, which product series are available, what each one powers, and how to think about choosing the right model for your application.
Why a Dedicated Power Supply Is Needed for Von Duprin Electrified Hardware Standard building power is 120 or 240 volts AC. Almost every electrified door hardware component, including electric latch retraction exit devices, electric strikes, and electromagnetic locks, operates on 12 or 24 volts DC. These are different voltages, different current types, and different levels of regulation. A raw connection from the building’s electrical system to a Von Duprin electrified device would destroy the device immediately. The power supply bridges that gap. It takes the high-voltage AC input from the building circuit and converts it into filtered, regulated low-voltage DC output that the hardware is designed to receive. Regulated output matters in this context. Electrified door hardware is sensitive to voltage variation. An unregulated power source can deliver spikes or drops that cause intermittent operation, premature component failure, or unreliable access control behavior. A regulated power supply holds the output within a tight tolerance band regardless of fluctuations in the AC
input, which is why Von Duprin’s purpose-built power supplies are specified for their own hardware rather than generic low-voltage supplies. For a deeper look at how fail mode interacts with power supply selection, the American Locksets blog post on fail safe vs fail secure covers the key decision points in plain language. The Von Duprin Power Supply Product Families Von Duprin has produced two main generations of power supplies. Understanding which generation applies to the hardware you are working with prevents compatibility problems before they happen. The PS873 Series (Legacy) The PS873 is Von Duprin’s legacy power supply line. It is no longer the current product, but it exists in a large number of installed commercial buildings across the United States and is still encountered regularly during service, upgrade, and replacement work. The PS873 delivers regulated output power that is field selectable for either 12 or 24 volts DC. It was designed to handle the high inrush current requirements of electrified latch retraction devices, which draw a brief surge of current at the moment the latch retracts. The PS873 offered multiple configurations through plug-in option boards, including two-zone control for separate device sequencing, fire alarm interface for automatic cut-off during an emergency, and access control relay boards for integration with card readers and keypads. A key compatibility note that matters for service and upgrade work: the option boards from the PS873 series are not compatible with the PS900 series power supplies. If a PS873 power supply is being replaced with a PS914 or another PS900 series unit, all option boards must also be replaced with the corresponding PS900 series boards. The hardware connectors and board dimensions differ between the two generations. Von Duprin offers the PS914-RFK as a retrofit kit that allows a PS914 main board assembly to be installed into an existing PS873 cabinet, which is useful when the cabinet and wiring are already in place and only the power supply board needs to be updated. The PS900 Series (Current) The PS900 series is Von Duprin’s current line of power supplies, designed to address the access control and life safety integration needs of modern commercial buildings. The PS900 series shares a common platform with a flat mounting design and polarized locking connectors for option boards that simplify installation and reduce wiring errors. All PS900 series power supplies accept universal AC input from 120 to 240 volts, which makes them compatible with standard US building circuits as well as international building power
without modification. The DC output is filtered and regulated, and all models provide AC input and DC output monitoring circuits with LED indicators that allow installers and technicians to verify operational status at a glance. The three main base models within the PS900 series differ primarily in output current capacity. PS902: Delivers 2 amps at 12 or 24 volts DC, field selectable by jumper. The PS902 is UL 294 listed for access control. It is used with Von Duprin MEL (Mechanical Electric Latch) exit devices, electric strikes, and electrified trim. The PS902-2RS configuration includes a 2-relay output board for controlling electric latch panic devices, electric strikes, or electrified trim. PS914: Delivers 4 amps at 12 or 24 volts DC, field selectable by jumper. The PS914 is the workhorse power supply for Von Duprin’s EL (Electric Latch Retraction) and QEL (Quiet Electric Latch Retraction) exit devices. It is specifically designed with high inrush current capability, which is required for powering the solenoid that retracts the latch bolt on EL and QEL equipped panic devices. The PS914-2RS configuration includes a 2-relay EL panic device control board. The PS914-2Q configuration includes a 2-relay QEL panic device control board for quiet latch retraction devices. With the appropriate option boards in place, the PS914 can control multiple Von Duprin electrified latch retraction devices from a single power supply. PS906: Delivers 6 amps at 12 or 24 volts DC, field selectable by jumper. The PS906 is listed under UL 294 and ULC-S318 and is built for applications requiring higher current capacity, such as installations with multiple electrified devices, electromagnetic locks alongside exit hardware, or card readers and other access control peripherals sharing the same power supply. It supports up to three polarized option board connectors and includes a high-voltage protective cover for the AC circuitry. What the Von Duprin Power Supply Actually Powers The question of what a specific Von Duprin power supply can power depends on two factors: the current capacity of the base unit, and which option boards are installed. Electric Latch Retraction (EL) Devices Von Duprin EL exit devices incorporate a solenoid that retracts the latch bolt electrically, allowing the door to be opened without depressing the push bar. This is the most common reason a dedicated Von Duprin power supply is needed. The PS914 is the designated power supply for Von Duprin EL devices because of its 4-amp output and high inrush current design. The inrush current at the moment of solenoid activation is higher than the steady-state operating current, and a power supply without high inrush capacity cannot reliably trigger the solenoid. Quiet Electric Latch Retraction (QEL) Devices Von Duprin QEL devices operate similarly to EL devices but use a quieter motor-driven latch retraction mechanism rather than a solenoid. They are specified for applications where audible
solenoid noise is undesirable, such as libraries, courtrooms, and healthcare facilities. The PS914-2Q option board is the correct board for controlling QEL devices through a PS914 power supply. Electric Strikes Von Duprin electric strikes and compatible third-party electric strikes can be powered through Von Duprin power supplies with the appropriate relay board installed. The PS902 is commonly used for electric strike applications where the lower 2-amp output is sufficient for the number and type of strikes on the circuit. Electrified Trim Von Duprin electrified outside trim, which allows the outside lever on an exit device to be locked or unlocked electronically for controlled entry, is powered through the same power supply infrastructure as EL and QEL devices. The relay boards coordinate the unlock signal from the access control system with the trim hardware. Fire Alarm Interface A fire alarm interface (FA) option board integrates the Von Duprin power supply with the building’s fire alarm panel. When the fire alarm activates, the fire alarm interface board receives the signal and cuts power to the electrified locking devices, allowing the doors to release to their fail-safe or fail-secure state as appropriate for the opening. This is a code-required integration on many commercial openings. The configuration, whether outputs cut power or maintain power during a fire alarm, is field selectable on FA-equipped models. Choosing the Right Von Duprin Power Supply The selection process for a Von Duprin power supply follows a straightforward sequence. First, identify the type of electrified devices being powered. EL exit devices require the PS914 with the 2RS relay board. QEL exit devices require the PS914 with the 2Q board. Electric strikes and electrified trim can typically use a PS902 depending on the total current draw of the installation. Applications with multiple devices or higher total current draw may require the PS906. Second, determine whether fire alarm interface is required. If the opening is connected to the fire alarm system, specify a model with an FA option board included. Third, confirm the total current draw of all devices on the circuit. A power supply should not be loaded above approximately 80 percent of its rated output to allow for inrush and to maintain voltage regulation. Add up the rated current draw of each electrified device, then select a base power supply that provides sufficient headroom.
Fourth, confirm whether the installation is a new construction job using a PS900 series supply or a service job on an existing PS873 installation. If the existing PS873 cabinet is being reused, the PS914-RFK retrofit kit allows the main board to be updated without replacing the enclosure. If the option boards are also being replaced, confirm that PS900 series boards are used, since PS873 option boards are not compatible with PS900 series main boards. Where the Power Supply Is Installed Von Duprin power supplies are wall-mounted or ceiling-mounted units installed near the door or in an accessible mechanical space. They are not visible from the door side during normal operation. Common installation locations include above a suspended ceiling tile near the door, in a nearby electrical or mechanical room, or in a dedicated enclosure on the wall adjacent to the opening. The power supply must be accessible for service, battery backup board installation if that option is included, and LED status monitoring. Running the wiring from the power supply to the exit device requires a low-voltage wire path through the door frame, typically through a transfer hinge or a power transfer device, depending on the door configuration. The Relationship Between the Power Supply and the Access Control System The Von Duprin power supply is not an access control panel. It is a power conversion and distribution device with relay outputs that interface with an access control system. The access control system, which includes the card reader, keypad, or credential device, makes the decision about whether access is authorized. When access is granted, the access control panel sends a signal to the relay on the Von Duprin power supply, which then momentarily energizes or de-energizes the electrified latch retraction device to allow the door to open. This two-component arrangement means the power supply and the access control panel are separate purchases with separate installation scopes. The power supply handles power conversion and device activation. The access control panel handles credential management, audit trails, and access logic. For an overview of how electrified panic devices fit into the larger exit hardware category, the American Locksets rim exit devices guide provides helpful context on where these components are used in commercial buildings. Frequently Asked Questions
Do all Von Duprin exit devices need a dedicated power supply? No. Mechanical Von Duprin exit devices have no electrical components and need no power supply. Only devices with an EL (Electric Latch Retraction) or QEL (Quiet Electric Latch Retraction) option require a Von Duprin power supply. Standard panic bars with mechanical dogging operate with no electrical connection. What is the difference between the PS902 and the PS914? The PS902 delivers 2 amps of output and is used for MEL exit devices, electric strikes, and electrified trim. The PS914 delivers 4 amps and is specifically designed with high inrush current capability for EL exit devices that use a solenoid to retract the latch. Using a PS902 to power an EL exit device is not recommended because the inrush current at solenoid activation can exceed the PS902’s output capacity. Can PS873 option boards be used with PS900 series power supplies? No. PS873 option boards are not compatible with PS900 series power supplies, and PS900 option boards cannot be used in PS873 enclosures. If replacing a PS873 with a PS914, all option boards must be changed to the corresponding PS900 series versions. The PS914-RFK retrofit kit allows the main board assembly to be installed in an existing PS873 cabinet. What does the FA designation mean on a Von Duprin power supply model number? FA stands for fire alarm interface. Models with the FA designation include a relay board that connects to the fire alarm panel. When the fire alarm activates, this relay responds to the signal and cuts power to the electrified devices, allowing them to transition to their fail-safe or fail-secure state as the installation requires. The FA board configuration is field selectable for either cut power or maintain power on alarm, depending on the fail mode requirements of the opening. Can one Von Duprin power supply run multiple exit devices? Yes, with the appropriate option boards. The PS914 with the correct relay boards can control multiple Von Duprin EL or QEL exit devices. The number of devices depends on the total current draw of the installation versus the rated output of the power supply. A PS906 with a higher current rating is used for installations with more devices or additional electrified hardware on the same circuit. Is the Von Duprin power supply the same as an access control power supply? No. The Von Duprin power supply is purpose-built to power Von Duprin electrified exit devices and includes relay boards that interface with an access control system. A generic access control power supply may not provide the inrush current needed for EL devices, and it does not include the Von Duprin-specific relay board configurations for device sequencing and fire alarm integration.
Conclusion The Von Duprin power supply is a dedicated low-voltage power conversion unit that provides the regulated DC output needed to operate Von Duprin electrified exit hardware. The PS900 series, which includes the PS902, PS914, and PS906 base models, is the current product line. The PS914 is the designated supply for EL and QEL exit devices. The PS902 serves electric strike and MEL device applications. Option boards expand each base model to include relay-controlled device outputs, fire alarm interface, zone sequencing, and other functions. Selecting the right model requires matching the supply’s output current and option board configuration to the specific Von Duprin devices on the opening, the access control system being used, and the fire alarm interface requirements of the installation. American Locksets stocks Von Duprin exit hardware and supporting components for commercial projects across the United States. Browse the Von Duprin panic devices and accessories category or call 1-877-471-4870 for specification support on any Von Duprin electrified opening.
A plain-language explanation of what the Von Duprin power supply is, what it does, which models exist, what they power, and how to choose the right one for your electrified door hardware installation.
