Specifications
Transformers
174 customer.honeywell.com 70-6910
AT175F Circuit Breaker Transformer
Provide power to 24 Vac circuits in heating/cooling control
systems. Intended for use in systems with predictable, uniform
loads. Can be used in any application that does not exceed the
listed ratings.
• Rated at 75 VA.
• Color-coded leadwires for primary connections and screw terminals
for secondary connections, fixed 1/4 inch (6 mm) male quick-
connects or color-coded leadwires for both primary and secondary,
are standard.
• Meet NEC Class 2 requirements.
• Meet Underwriters Laboratories Inc. Standard UL 1585 and are
identified. Class 2 not wet, Class 3 wet.
Temperature Rating: -20 F to +105 F (-29 C to +41 C)
Frequency: 60 Hz
Electrical Connections (main)
Primary: 9 in. leadwires
Secondary: 9 in. leadwires
Includes: Button for manually resetting the circuit breaker and metal
end bells.
Approvals:
Canadian Standards Association: CSA Certified: A & B models.
Underwriters Laboratories, Inc. UL Listed: A,C,F models. File #
E14881
AT20; AT40 NEMA Standard Universal Stripped-Down Transformer
Power a 24V control system; for direct mounting, or horizontal or
vertical foot-mounting.
• Channel frame mounting feet and slots allow for the three mounting
positions.
• Color-coded leadwires for primary connections.
• Overload protection provided.
• Energy limiting, meet NEMA DC20-1992 Standard.
• Meet NEC Class 2 not wet, Class 3 wet and U.L. 1585 requirements.
• Mount within proper enclosure.
Temperature Rating: -20 F to +105 F (-29 C to +41 C)
Frequency: 50 Hz; 60 Hz
Electrical Connections (main)
Primary:
9 in. color coded primary and secondary leadwires
Secondary: 9 in. color coded primary and secondary leadwires
Approvals:
Canadian Standards Association: Certified
Underwriters Laboratories, Inc. UL Component Recognized.
Product Number
Electrical Ratings
Mounting
Dimensions, Approximate
Voltage
Output (inch) (mm)Primary Secondary
* AT175F1023 120 Vac,
208 Vac,
240 Vac
27.5 V.O.C. 24 Vac at
75 VA
Includes 1/2 14 NPSM conduit connector and lock nut for
mounting on plate or panel (not included) with 7/8 in. knockout,
and feet for surface mount.
3 3/16 in. high x
2 3/16 in. wide x
3 15/16 in. deep
81 mm high x
56 mm wide x
102 mm deep
* AT175F1031 208 Vac,
277 Vac,
480 Vac
27.5 V.O.C. 24 Vac at
75 VA
Includes 1/2 14 NPSM conduit connector and lock nut for
mounting on plate or panel (not included) with 7/8 in. knockout,
and feet for surface mount.
3 3/16 in. high x
2 3/16 in. wide x
3 15/16 in. deep
81 mm high x
56 mm wide x
102 mm deep
* TRADELINE models • SUPER TRADELINE models
Product Number
Electrical Ratings
NEMA Rating Mounting
Dimensions, Approximate
Voltage
Output (inch) (mm)Primary Secondary
* AT20A1123 120 Vac 26.5 V.O.C. 24 Vac at 19 VA NEMA type B Channel Frame Mounting allows for
Direct, Horizontal, or Vertical Foot
mounting.
2 in. high x
2 1/4 in. wide x
1 7/8 in. deep
50.8 mm high x
57 mm wide x
47.6 mm deep
* AT40A1121 120 Vac 26.5 V.O.C. 24 Vac at 40 VA NEMA type D Channel Frame Mounting allows for
Direct, Horizontal, or Vertical Foot
mounting.
2 3/32 in. high x
2 5/8 in. wide x
2 3/16 in. deep
53 mm high x
67 mm wide x
56 mm deep
* AT40A1139 240 Vac 26.5 V.O.C. 24 Vac at 40 VA NEMA type D Channel Frame Mounting allows for
Direct, Horizontal, or Vertical Foot
mounting.
2 3/32 in. high x
2 5/8 in. wide x
2 3/16 in. deep
53 mm high x
67 mm wide x
56 mm deep
* TRADELINE models • SUPER TRADELINE models