White-Rodgers 90-T40M3 Transformer

The White-Rodgers 90-T40M3 is a Class 2 transformer engineered for reliable 24V control circuit power in commercial and residential HVACR applications. This 40VA HVAC transformer features a multi-tap primary voltage configuration, supporting 120V, 208V, and 240V inputs, making it a versatile multi-volt control transformer for various field service requirements. As an energy limiting transformer, it provides essential circuit protection for thermostats, relays, and contactors. The 90-T40M3 White-Rodgers model is built with a closed construction and includes a universal mounting plate (multi-mount) to facilitate easy installation in tight control cabinets. For technicians, the color-coded primary and secondary wire leads ensure clear identification and speed up the wiring process, maintaining 1.67 amps of output for secondary control logic without excessive voltage drop.

• Universal Compatibility: Multi-tap primary (120/208/240VAC) allows one unit to cover most standard HVAC equipment installations.
• Simplified Mounting: The multi-mount design with an included plate supports foot, hub, or panel mounting options.
• Enhanced Safety: Class 2 rating and energy-limiting design protect downstream low-voltage components from overcurrent.
• Standardized Wiring: Industry-standard color-coded leads (Black-Common, White-120V, Red-208V, Orange-240V) reduce wiring errors.

What is the maximum current draw on the 24V side?
At a 40VA rating, the secondary side provides approximately 1.67 Amps at 24VAC. Always calculate the total VA load of all connected contactors and relays to ensure you stay within this limit.

How should unused primary leads be handled?
Unused voltage taps must be individually capped with wire nuts. Do not bridge unused wires together, as this will short the primary winding and damage the unit.

Can this replace a transformer with a lower VA rating?
Yes, a 40VA transformer can safely replace a 20VA or 30VA unit, provided the voltages match, as it offers more capacity for the control circuit.

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.