White-Rodgers 90-T40F3 HVAC Control Transformer

The White-Rodgers 90-T40F3 HVAC Control Transformer is a panel- or equipment-mounted transformer that steps line voltage down to low-voltage control power for thermostats, relays, contactors, gas valves, and HVAC control circuits found in residential and commercial systems. Used in furnaces, air handlers, refrigeration systems, and HVAC control panels, it provides reliable continuous-duty operation for temperature control and equipment coordination. Maintenance teams, HVAC technicians, and electrical contractors rely on this transformer for replacement, control-system repair, retrofit projects, and restoring stable low-voltage power distribution. Key specifications include: Brand White-Rodgers; Part Number 90-T40F3; Product Type Control Transformer; Application Low Voltage HVAC Power Conversion; Transformer Function Step-Down Voltage Supply; Compatible Equipment Furnaces, Air Handlers, and HVAC Systems; Voltage Type Low Voltage Control Power; Mounting Type Panel or Equipment Mounted; Industrial Use Residential and Commercial HVAC Systems; Operating Environment Continuous-Duty Electrical Applications; System Compatibility Thermostats, Relays, and Gas Valve Circuits; Construction Type HVAC Control Power Transformer; Usage Type HVAC and Refrigeration Equipment Control. Common Replacements: Honeywell AT140A Transformer, Packard PF42440 Transformer, Mars 50354 Control Transformer.