EMERSON / White-Rodgers 90-T40M3 Control Transformer

Description:

The EMERSON / White-Rodgers 90-T40M3 Control Transformer is used in residential, commercial, and industrial HVAC systems for stepping down line voltage to low voltage control power for thermostats, relays, gas valves, contactors, and HVAC control circuits. Commonly installed in furnaces, air handlers, refrigeration systems, rooftop HVAC units, and industrial control panels. Maintenance teams, HVAC technicians, and electrical contractors use this part for transformer replacement, control system repair, retrofit projects, and restoration of low voltage power distribution.

Applications:

The EMERSON 90-T40M3 transformer is commonly used in HVAC and industrial environments requiring reliable low voltage power conversion and dependable control circuit operation. It is frequently installed in furnace control systems, air conditioning equipment, refrigeration assemblies, and automation panels where stable 24VAC output is critical for maintaining thermostat communication and HVAC component control. The transformer supports continuous-duty operation in heating, cooling, and industrial process control applications.

Technical Specifications:

• Brand: EMERSON / White-Rodgers
• Part Number: 90-T40M3
• Alternate Number: 90T40M3
• Product Type: Class 2 Control Transformer
• Power Rating: 40 VA
• Primary Voltage: 120/208/240 VAC
• Secondary Voltage: 24 VAC
• Secondary Current Rating: 1.67A
• Frequency Rating: 50/60 Hz
• Transformer Type: Step-Down HVAC Control Transformer
• Mounting Style: Multi-Mount / Foot Mount
• Primary Connection Type: Lead Wires
• Secondary Connection Type: Lead Wires
• Application: Low Voltage HVAC Power Conversion
• Compatible Equipment: Furnaces, Air Handlers, and HVAC Systems
• Industrial Use: Residential and Commercial HVAC Systems
• Construction Type: Class 2 Energy Limiting Transformer
• Operating Environment: Continuous-Duty Electrical Applications

Common Replacements:

• Honeywell AT140A1000 Transformer
• Packard PF42440 Control Transformer
• Mars 50354 Class 2 Transformer