Honeywell AT120A Installation Instructions Download Page 2

AT120A, AT140A, AT150A, AT175A UNIVERSAL TRANSFORMERS

69-0251-3

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Mounting

The transformer can be mounted in one of three ways:

— foot mounting.
— plate mounting.

— mounting through outlet box knockout hole.

Foot Mounting

1.

Mount the transformer using screws (not supplied) 

through the four 3/16 in. x 3/8 in. holes in the 
mounting feet. 

2.

Make line voltage primary connections within an 

approved enclosure. See Fig. 1. 

3.

Discard the mounting plate.

Fig. 1. Foot mounting.

Plate Mounting

MOUNTING PLATE TO TRANSFORMER

Mount the plate to the transformer in either of two 
positions (see Fig. 2):
• at clamp on primary end bell.
• at laminations.

Fig. 2. Mounting plate to transformer in either 

of two positions.

MOUNTING PLATE AT CLAMP ON PRIMARY END BELL

1.

Turn the screw on the clamp almost all the way out.

2.

Hold the mounting plate with the keyhole slots up 
and the raised portion of the large center knockout 
away from you.

3.

From the back, thread the primary leadwires 
through the round center hole in the plate.

4.

Fit the clamp and screw through the round hole.

5.

While holding the plate in place, tighten the 
setscrew securely against the rim of the hole. 
See Fig. 3. Avoid damaging the leadwires with the 
screwdriver.

USE SCREWS OR 
BOLTS THROUGH
SLOTS (4) IN
MOUNTING FEET

SCREW TERMINALS 
FOR SECONDARY 
CONNECTIONS

MOUNTING 
FOOT (2)

LEADWIRES 
FOR PRIMARY 
CONNECTIONS

M9161

PLATE MOUNTED AT CLAMP ON  PRIMARY END BELL

MOUNTING 
PLATE

MOUNTING PLATE

PLATE MOUNTED AT THE LAMINATIONS

M9162

END
BELL

CLAMP SCREW 
AND CLAMP

RAISED PORTION OF 
LARGE CENTER KNOCKOUT

LEADWIRES 
FOR PRIMARY 
CONNECTIONS

LEADWIRES 
FOR PRIMARY 
CONNECTIONS

MOUNTING
 SCREW

SCREW 
TERMINALS FOR
SECONDARY
CONNECTIONS

SCREW 
TERMINALS FOR
SECONDARY
CONNECTIONS

MOUNTING FEET ON "A" MODELS ONLY.

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Summary of Contents for AT120A

Page 1: ...the product or cause a hazard ous condition 2 Check the ratings given in the instructions and on the product to make sure the product is suitable for your application 3 Installer must be a trained experienced service technician 4 After installation is complete check out product operation as provided in these instructions CAUTION Electrical Hazard Can cause electrical shock or equipment damage Disc...

Page 2: ... the way out 2 Hold the mounting plate with the keyhole slots up and the raised portion of the large center knockout away from you 3 From the back thread the primary leadwires through the round center hole in the plate 4 Fit the clamp and screw through the round hole 5 While holding the plate in place tighten the setscrew securely against the rim of the hole See Fig 3 Avoid damaging the leadwires ...

Page 3: ...necessary Mount the plate on the outlet box using two screws obtained locally Mounting Through Outlet Box Knockout Hole The transformer can be mounted on an outlet box using the clamp on the primary end bell The mounting plate is not used To mount the transformer on an outlet box 1 Turn the clamp screw almost all the way out 2 From outside box thread the primary leadwires through suitable 7 8 in k...

Page 4: ...wer supply and perform a voltage check 1 Place controlled equipment in operation and observe through one complete cycle 2 Using a voltmeter check for proper primary and secondary voltages 3 If voltage readings are incorrect be sure primary voltage connections are made correctly 4 Measure voltage again a If correct primary voltage is measured and secondary voltage is significantly less than the vol...

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