Install Instructions

ManualsBrandsResideo ManualsTransformersFoot/Plate Mounted 120/208/240 Vac Transformer w/ 13" Lead Wires, Built in Protection & Primary Winding Burnout

INSTALLATION INSTRUCTIONS

69-1641EF-02

AT20, AT40, AT72D, AT87, AT88

AT Transformers

APPLICATION

The AT20, AT40, AT72, AT87 and AT88 Transformers are

step-down transformers used primarily for powering 24

Vac control systems. They can be used in any 24 Vac

application that does not exceed the transformer volt-

ampere (VA) rating.

The Transformers will replace all equivalent Resideo and

competitive transformers with similar primary voltage

requirements, equal or smaller VA ratings and similar

mounting configurations.

Transformer voltage ratings (primary and secondary),

wiring connection type, and fusing are listed in Table 1.

The transformers are Underwriters Laboratories Inc.

component recognized and Canadian Standards

Association listed and meet NEC Class 2 not wet, Class

3 wet requirements as specified by NEMA Standard

DC-20.

SPECIFICATIONS

Models:

See Table 1.

Table 1. Transformer Model and Electrical Specifications.

Transformer complies with 24 volt NEMA Standard DC-20.

Available with female quick-connect terminals on all leadwires.

Thermal fuses in primary on 208V/240V models for overload protection.

Model

Primary Secondary

Output at

100 Percent

Power Rating

Overload

Protection

Voltage and

Frequency Wiring Connection Voltage Wiring Connection

AT20

120 Vac, 50/60 Hz Two 9 in. (229 mm)

leadwires

24 Vac Two 9 in. (229 mm)

leadwires

20 VA Energy

Limited

AT40

120 Vac, 50/60 Hz 40 VA

240 Vac, 50/60 Hz

AT72D

120 Vac, 50/60 Hz Two screw

terminals

240 Vac, 50/60 Hz Three 9 in. (229

mm) leadwires

AT87A

120 Vac, 50/60 Hz Two 13 in. (330

mm) leadwires

50 VA

208 Vac, 50/60 Hz

240 Vac, 50/60 Hz

AT88A 120Vac, 50/60 Hz Two 12 in. (305

mm) leadwires

24 Vac Two 12 in. (305

mm) leadwires

75 VA Fuse in

secondary

208/240 Vac, 50/60

400 Vac, 50/60 Hz

480 Vac, 50/60 Hz

Summary of content (12 pages)

PAGE 1
AT20, AT40, AT72D, AT87, AT88 AT Transformers INSTALLATION INSTRUCTIONS APPLICATION Transformer voltage ratings (primary and secondary), wiring connection type, and fusing are listed in Table 1. The AT20, AT40, AT72, AT87 and AT88 Transformers are step-down transformers used primarily for powering 24 Vac control systems. They can be used in any 24 Vac application that does not exceed the transformer voltampere (VA) rating. The transformers are Underwriters Laboratories Inc.
PAGE 2
AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS INSTALLATION A in. B mm in. C mm in. D mm in. USE SCREWS OR BOLTS THROUGH SLOTS (4) IN MOUNTING FEET E mm in. mm AT40C 2-13/32 61 7/8 22 1-3/4 44 2-3/16 56 2-7/8 73 AT87A 2-13/32 61 1 1-3/4 44 2-1/16 52 3 25 76 When Installing This Product… 1. 2. 3. 4. Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition.
PAGE 3
AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS Mounting the AT72D Transformer. Mounting Transformer and Plate to Electrical Box Mount the transformer to meet the application. Use one of the methods illustrated. The transformer can be mounted in any position. The mounting plate can be mounted to 4 in. x 4 in. boxes with regular and irregular spaced mounting holes, to 2 in by 4 in. boxes and to 4 in. octagonal boxes. See Fig. 9. Foot Mounting. 1. 2. 1. 2. Discard mounting plate.
PAGE 4
AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS M12126 Fig. 5. Tighten clamp securely against rim of round hole. WITH RAISED PORTION OF KNOCKOUTS FACING YOU: 1. PRY UP TOP SECTION OF LARGE KNOCKOUT BY INSERTING SCREWDRIVER FIRST AT ONE SIDE OF SLOT AND THEN AT THE OTHER SIDE. 2. THEN PRY UP BOTTOM SECTION OF KNOCKOUT. 3. REMOVE BOTH SECTIONS OF KNOCKOUT WITH PLIERS. SHADED AREAS REPRESENT KNOCKOUTS AND SCREW SLOTS USED WITH 2 X 4 INCH OR OCTAGONAL OUTLET BOXES. M9188A Fig. 6.
PAGE 5
AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS REGULAR 4 X 4 INCH BOX (2) Mounting Transformer and Plate to Electrical Box. IRREGULAR 4 X 4 INCH BOX (MOUNTING HOLES IN BOX ARE SLIGHTLY INDENTED) OCTAGON BOX The mounting plate can be mounted in 4 in. x 4 in. boxes with regular and irregular spaced mounting holes, and on 4 in. octagonal boxes (Fig. 9). 1. 2. LOAD Use the screws supplied with the junction box.
PAGE 6
AT20, AT40, AT72D, AT87, AT88 AT TRANSFORMERS CHECKOUT 2 COMMON 208 VAC 240 VAC BLACK RED 1 24 VAC 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. ORANGE 1 SECONDARY CONNECTIONS ARE BLUE AND YELLOW LEADWIRES. 2 BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER WINDING ONLY AND NOT THE EXTERNAL CIRCUIT. M20661 Fig. 13. AT88 Transformer schematic. www.resideo.
PAGE 7
Transformateurs AT AT20, AT40, AT72D, AT87, AT88 NOTICE D'INSTALLATION APPLICATION Les transformateurs abaisseurs AT20, AT72, AT87 et AT88 sont utilisés principalement pour alimenter les systèmes de régulation 24 V c.a. Ils peuvent être utilisés dans toutes les applications 24 V c.a. qui ne dépassent pas la valeur nominale en voltampères (VA) du transformateur.
PAGE 8
TRANSFORMATEURS AT AT20, AT40, AT72D, AT87, AT88 INSTALLATION A B C po. mm po. mm D po. mm po. INSÉRER DES VIS OU DES BOULONS DANS LES FENTES (4) DU SOCLE DE MONTAGE E mm po. mm AT40C 2-13/32 61 7/8 22 1-3/4 44 2-3/16 56 2-7/8 73 AT87A 2-13/32 61 1 1-3/4 44 2-1/16 52 3 25 76 Avant d'installer ce produit… 1. 2. 3. 4. Lire les présentes instructions attentivement. Le fait de ne pas les suivre pourrait endommager le produit ou constituer un danger.
PAGE 9
TRANSFORMATEURS AT AT20, AT40, AT72D, AT87, AT88 Montage du transformateur AT72D 3. Monter le transformateur en tenant compte de l'application. Choisir l'une des méthodes illustrées. Le transformateur peut être monté dans n'importe quelle position. 4. Montage sur socle 1. 2. Mettre de côté la plaque de montage. Insérer des vis ou des boulons dans les fentes du socle de montage pour fixer le transformateur sur la surface de montage. 5.
PAGE 10
TRANSFORMATEURS AT AT20, AT40, AT72D, AT87, AT88 1. 2. 3. Utiliser les vis fournies avec la boîte électrique. Insérer les vis dans les bons trous de montage de la plaque et fixer le transformateur et la plaque sur la boîte. Défoncer les ouvertures défonçables correspondant aux trous de montage de la plaque, s'il y a lieu. M12126 Fig. 5. Bien serrer l'étrier sur le rebord du trou rond. PLACER LA PARTIE SURÉLEVÉE DE L'OUVERTURE DÉFONÇABLE VERS SOI, PUIS : 1.
PAGE 11
TRANSFORMATEURS AT AT20, AT40, AT72D, AT87, AT88 TRANSFORMATEUR INSÉRER DES VIS OU DES BOULONS DANS LES FENTES (4) DU SOCLE DE MONTAGE. PLAQUE T AN R RT PO ME IM UNT OR F E O M ANS SID TR HER T O CONDUCTEURS DES CONNEXIONS PRIMAIRES BORNES Á VIS DES CONNEXIONS SECONDAIRES SOCLE DE MONTAGE (2) MF20659A Fig. 10. Montage sur socle du transformateur AT87.
PAGE 12
TRANSFORMATEURS AT AT20, AT40, AT72D, AT87, AT88 CÂBLAGE 2 1. 2. 3. COMMUN Couper l'alimentation électrique avant d'installer le transformateur. Le câblage doit être conforme aux codes et aux règlements d'électricité locaux. Poser un ruban sur chacun des conducteurs à découvert non utilisés. Raccorder les conducteurs primaires à l'alimentation secteur. Voir les Fig. 11 à 13. Raccorder les conducteurs secondaires du transformateur au système de régulation 24 V c.a. 208 V C.A. 240 V C.A.