Honeywell AT120A, AT140A, AT150A, AT175A Installation Instructions Download Page 4

69-0251—2

4

Home and Building Control

Home and Building Control

Helping You Control Your World

Honeywell Inc.

Honeywell Limited—Honeywell Limitée

1985 Douglas Drive North

740 Ellesmere Road

Golden Valley, MN 55422

Scarborough, Ontario
M1P 2V9

Printed in China

Fig. 6—Schematics for single and multitap
transformers.

Checkout

CAUTION

Do not short transformer secondary terminals.
Overload current protection is inherent on AT120,
AT140, and AT150. A fused 3.5 Amp secondary
is used on AT175.

VOLTAGE CHECK

After installation is complete, turn on power supply and

perform a voltage check.

1. Place controlled equipment in operation and observe

through one complete cycle.

2. Using a voltmeter, assure proper primary and sec-

ondary voltages exist.

3. If voltage readings are incorrect, assure primary volt-

age connections are made properly.

4. Measure voltage again.

• If proper primary voltage is measured and sec-

ondary voltage is significantly less than the volt-
age shown on the regulation curves, transformer
winding is damaged. Replace transformer and
repeat checkout procedures.

• If primary voltage is 0V, assure power supply is

connected properly or repair if necessary. Repeat
checkout procedures.

5. Do not put system into operation unless correct pri-

mary and secondary voltages are measured.

VOLTAGE 
VARIES
WITH MODEL

2

SECONDARY

M9182

COMMON

PRIMARY

BLACK

120 V - WHITE
208 V - RED
240 V - ORANGE
277 V - BROWN
480 V - BLACK/RED 

1

3

SINGLE VOLTAGE MODELS

208 V

2

SECONDARY

COMMON

PRIMARY

BLACK

ORANGE  

1

3

208/240 VAC MODELS

240 V

RED

208 V

120 V

2

SECONDARY

COMMON

PRIMARY

BLACK

ORANGE  

1

1

SECONDARY CONNECTIONS ARE SCREW TERMINALS, 1/4 INCH
 QUICK-CONNECTS OR BLUE AND YELLOW LEADWIRES.

BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER 
WINDING ONLY AND NOT THE EXTERNAL CIRCUIT.

SOME MODELS AVAILABLE WITH 1/4 INCH QUICK CONNECTS.

2

3

3

120/208/240 VAC MODELS

240 V

RED

WHITE

Summary of Contents for AT120A, AT140A, AT150A, AT175A

Page 1: ...inals 50 VA AT175A 120 208 240 9 in leads 27 5 24 0 Screw terminals 75 VA Installation WHEN INSTALLING THIS PRODUCT 1 Read these instructions carefully Failure to follow them could damage the product or cause a hazardous condition 2 Check the ratings given in the instructions and on the product to make sure the product is suitable for your application 3 Installermustbeatrained experiencedservicete...

Page 2: ... 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 Fig 3 When screw is tightened clamp holds plate on transformer PLATE MOUNTED AT CLAMP ON PRIMARY END BELL MOUNTING PLATE MOUNTING PLATE PLATE MO...

Page 3: ...pment damage 1 Make primary connections to the line voltage power supply On multitap models be sure to use correct leads for available power supply See Fig 6 2 On multitap models insulate the ends of the unused leads using wire nuts or capping with a solderless connec tor 3 Make secondary connections to 24 Vac control cir cuit To mount the plate at the laminations 1 Removethelargerectangularknocko...

Page 4: ...easure voltage again If proper primary voltage is measured and sec ondary voltage is significantly less than the volt age shown on the regulation curves transformer winding is damaged Replace transformer and repeat checkout procedures If primary voltage is 0V assure power supply is connected properly or repair if necessary Repeat checkout procedures 5 Do not put system into operation unless correc...

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