Functional Devices TR50VA017 Transformer

For industrial and commercial secondary power applications, the Functional Devices TR50VA017 Transformer provides a reliable 50VA power rating, specifically engineered to step down high-voltage primary sources of 480/277/208 Vac to a stabilized 24 Vac secondary output. This multi-tap control transformer is a staple for HVACR contractors who require a versatile solution for powering 24V control circuits, building automation systems, and magnetic switches in complex electrical environments. Its split-bobbin construction ensures superior isolation, while the integrated circuit breaker overcurrent protection provides a resettable safety mechanism that prevents downtime and protects downstream components from damage due to shorts or overloads.

Designed for rapid field installation, the TR50VA017 features both foot and single threaded hub mount options, allowing it to be secured directly to electrical knockouts or flat surfaces within a panel. The Class 2 UL 5085-3 listing guarantees compliance with stringent safety standards for low-voltage power supplies, making it suitable for driving sensors, relays, and digital I/O circuits in temperature control architectures. With its wide operating temperature range of -30°F to 140°F, this unit maintains consistent performance in demanding mechanical rooms and rooftop units.

• Multi-Tap Primary Input: Supports 208V, 277V, and 480V, reducing the need to carry multiple SKUs for different site voltages.
• Integrated Safety: The built-in manual reset circuit breaker eliminates the need for external inline fuses and simplifies troubleshooting.
• Flexible Mounting: Provides NPT threaded hub and foot-mount configurations to fit standard junction boxes and enclosures.
• Code Compliance: UL Listed Class 2 rating ensures the unit meets safety requirements for energy-limited control circuits.
• Durable Construction: High MTBF and split-bobbin design maximize shelf life and operational reliability in industrial environments.

Can the TR50VA017 be used to power multiple HVAC controllers?
Yes, provided the total current draw of all connected devices does not exceed the 50VA rating (approximately 2.08 Amps at 24V). Always calculate the total VA load of your actuators and controllers before installation.

What is the purpose of the built-in circuit breaker on this transformer?
The circuit breaker serves as overcurrent protection. If a short circuit or overload occurs on the secondary 24V side, the breaker trips to protect the transformer coils. It can be manually reset once the fault is cleared.

How do I wire the primary side for 480V versus 208V?
The unit includes color-coded leads for specific voltages. According to the wiring diagram, the Black lead is Common, the Red lead is for 208V, the Brown lead is for 277V, and the Grey lead is used for 480V. Always cap off unused primary leads with wire nuts.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.