Instructions / Assembly

AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
® U.S. Registered Trademark
© 2016 Honeywell International Inc.
69-1641EF—01 M.S. Rev. 08-16
Printed in United States
WIRING
1. Disconnect power supply before installing
transformer. All wiring must comply with local
electrical codes and ordinances. Tape all
unused exposed leadwires separately.
2. Connect primary leadwires to line voltage power
supply. See Fig. 11 through 13.
3. Connect transformer secondary leadwires to 24
Vac control system.
Fig. 11. AT20/AT40 Transformer schematic.
Fig. 12. AT72D, AT87A Transformer schematic.
Fig. 13. AT88 Transformer schematic.
CHECKOUT
After installation is complete, turn on power supply.
Placed controlled equipment into operation and
observe through at least one complete cycle. Make
sure it functions as intended.
SECONDARY CONNECTIONS ARE BLUE AND YELLOW
LEADWIRES.
BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER
WINDING ONLY AND NOT THE EXTERNAL CIRCUIT.
WHITE (120V) OR ORANGE (240V)
COMMON
1 24 VAC
2
BLACK
1
2
M20660
1
1 SECONDARY CONNECTIONS ARE SCREW TERMINALS.
2 BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER
WINDING AND NOT THE EXTERNAL CIRCUIT.
2
120 VAC
WHITE
208 VAC
240 VAC
BLACK
RED
ORANGE
24 VAC
M18321
SECONDARY CONNECTIONS ARE BLUE AND YELLOW
LEADWIRES.
BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER
WINDING ONLY AND NOT THE EXTERNAL CIRCUIT.
ORANGE
RED
1
2
M20661
COMMON
1 24 VAC
2
BLACK
208 VAC
240 VAC