Altronix T2428175 Open Frame Transformer 175VA
The Altronix T2428175 is a 175VA open frame transformer engineered for step-down conversion in security infrastructure and access control installations. It transforms 115VAC primary input to 24VAC or 28VAC secondary output, delivering a maximum of 7.25 amps at rated capacity. The open frame construction eliminates unnecessary housing, allowing direct integration into electrical enclosures, control panels, and wall-mounted cabinets where real estate and thermal management matter.
Key Features
- 175VA Capacity: Sufficient to power multiple door strikes, magnetic locks, and low-draw camera/sensor loads simultaneously. At 7.25A output, this covers mid-range access control and auxiliary security circuits without oversizing, which keeps unnecessary heat generation and cost in check.
- 115VAC Primary Input: Standard US utility voltage—compatible with any standard 15A or 20A circuit breaker without special wiring or conditioning.
- Dual Secondary Output (24/28VAC): Field-selectable or dual-tap design accommodates both 24VAC and 28VAC devices. This flexibility lets you standardize on one transformer for mixed 24V and 28V equipment in the same installation without inventory bloat.
- 7.25A Maximum Output Current: Translates to approximately 174 watts of continuous available power. Enough for a pair of solenoid locks (typically 0.5–1.5A each) plus camera/sensor backup circuits, with headroom remaining. Verify device datasheets against this limit before final circuit design.
- Open Frame Design: No external enclosure means lower cost, smaller footprint, and direct panel or DIN rail mounting inside existing cabinets. You handle environmental protection via the host enclosure—no redundant shielding. Simplifies wiring diagrams and reduces assembly time.
- Lifetime Limited Warranty: Altronix stands behind the core transformer; typical coverage includes manufacturing defects and internal failures under normal operation. Verify terms with warranty documentation before deployment in mission-critical access control circuits.
Integration & Deployment Context
The T2428175 is the workhorse for smaller distributed power architectures in security systems. Install it inside a wall-mounted access control panel to supply door lock solenoids, magnetic strike plates, and auxiliary sensors on the same secondary circuit. Its 175VA capacity aligns with single-door or two-door installations; larger multi-door systems or high-current lock configurations may require multiple units or a higher-capacity model. Always confirm load calculation—sum the nameplate current draw of all downstream devices and add 20% for inrush transients. If that total exceeds 7.25A, choose a higher-VA unit to avoid nuisance breaker trips or voltage sag under peak load.
Frequently Asked Questions
Q: Can I use the T2428175 to power IP security cameras directly?
A: Not as a primary feed. The T2428175 is designed for low-draw DC-regulated supplies downstream (e.g., camera PoE injectors, sensor modules, or backup circuits). If you have cameras requiring dedicated 24VAC feeds, confirm their current draw and ensure the total does not exceed 7.25A. Most IP cameras use PoE anyway, making this transformer useful for supplemental 24V circuits rather than camera backbone power.
Q: What is the difference between 24VAC and 28VAC output?
A: Some legacy access control devices and solenoids are rated for 28VAC nominal; others standardize on 24VAC. The T2428175 accommodates both, so you can retrofit it into systems with mixed equipment. Always cross-reference the voltage rating on your lock or solenoid's nameplate—applying the wrong voltage can shorten solenoid life or prevent full actuation.
Q: Is the T2428175 suitable for outdoor enclosures?
A: The transformer itself is not IP-rated; it relies on the host enclosure for environmental protection. If your access control panel is mounted outdoors, ensure the enclosure is IP66-rated and vented to manage transformer heat. Open frame design means you must manually account for rain, dust, and temperature swings in the cabinet design.
Q: How do I calculate if the T2428175 is large enough for my installation?
A: Sum the continuous current draw of all devices on the 24/28VAC secondary circuit. Example: two solenoid locks at 1A each + one sensor module at 0.5A = 2.5A total. The T2428175's 7.25A limit means you have headroom. If your total is above 6A, add a 20% margin for inrush and transient spikes; if that result exceeds 7.25A, upgrade to a higher-capacity Altronix transformer.
Q: Does the T2428175 include mounting hardware or a DIN rail kit?
A: The open frame transformer ships as a bare unit. Most integrators mount it directly to a DIN rail inside a cabinet using standard brackets or secure it with M4 fasteners to the enclosure backplate. No pre-included hardware—plan your mechanical layout during panel design.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix T2428175 is a no-frills step-down workhorse that has seen decades of field deployment in access control cabinets across North America. The 175VA capacity and dual 24/28VAC output make it a pragmatic choice for retrofit or new-build installations where legacy and modern equipment coexist on the same power distribution rail. Open frame design means you save cost and complexity, but it also means you own the thermal and environmental management.
Technical Highlights:
- 7.25A Maximum Output: At 175VA, this covers two heavy solenoid locks (1A–1.5A each) plus auxiliary sensors and indicator circuits without pushing toward saturation. The margin is tight in dense multi-door applications; load planning is mandatory before wiring.
- Dual Secondary (24/28VAC): Field-selectable output eliminates the need to stock two transformer SKUs. A real advantage when integrating older 28VAC strike plates into 24VAC-dominant control systems. Verify jumper or tap configuration before commissioning to avoid voltage mismatch and solenoid coil burnout.
- 115VAC Primary: Standard utility voltage with no exotic wiring requirements. Integrates into any site panel or UPS backup circuit without conditioning gear. Keep the primary feed on a dedicated 20A breaker if multiple secondary circuits or inrush loads are present.
Deployment Considerations:
- Thermal Management: Open frame means no active cooling. In high-ambient installations (attics, equipment closets above roofs), transformer temperature will rise. Check the transformer's operating range against site conditions; if sustained load pushes toward 7.25A in a warm enclosure, consider stepping up to a larger unit or splitting the load across two transformers on separate breakers.
- Inrush and Transient Protection: Solenoid locks draw large instantaneous currents during strike actuation. A 20% current margin during planning helps absorb these spikes and prevents voltage sag that would trip door sensors or flicker indicator LEDs. Pair the T2428175 with a soft-start relay or diode pack if you experience nuisance failures in high-cycle environments.
- No Integrated Fusing or Isolation: The transformer itself is passive. Downstream fusing, breakers, and relay protection are your responsibility. Wire the secondary circuit with appropriately sized breakers and fusing per the National Electrical Code and local authority requirements.
Deploy the T2428175 in single-door or two-door secured entry installations where load is predictable and stable, or as a supplemental power rail in larger multi-door panels to handle solenoid and sensor circuits separate from main camera/network infrastructure. Its lifetime warranty and low cost make it a safe choice for straightforward access control power conversion; size it conservatively and verify your load calcs before first energization.
