Chamberlain LiftMaster Professional BG770 Manual

Doc 01-G0674
Rev D
Installation and Maintenance Manual
Barrier Gate Operator
Models BG770 & BG790

2Contents
Doc 01-G0674
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Contents
General Product Information ________________________________________________ 4
Specifications _______________________________________________________________________ 4
Safety Instructions _________________________________________________________ 6
Before Installation____________________________________________________________________ 6
During Installation____________________________________________________________________ 6
After Installation _____________________________________________________________________ 7
Preparing the Installation ___________________________________________________ 8
Unpack Carton_______________________________________________________________________ 8
Preparing the Site ____________________________________________________________________ 9
Preparing the Operator _______________________________________________________________ 10
Installation ______________________________________________________________ 11
Step 1: Mounting___________________________________________________________________ 11
Step 2: Arm Fabrication _____________________________________________________________ 12
Step 3: Wiring Connections __________________________________________________________ 13
Step 4: Arm Attachment_____________________________________________________________ 14
Step 5: Arm and Turnbuckle Shaft Adjustments __________________________________________ 16
Step 6: Limit Switch Adjustments _____________________________________________________ 18
Optional Accessories_______________________________________________________ 19
Vehicle Detectors ___________________________________________________________________ 19
Radio Controls______________________________________________________________________ 19
Card Readers, Keypads, or other________________________________________________________ 20
Operating Instructions _____________________________________________________ 21
Electrical Operation__________________________________________________________________ 21
Manual Operation ___________________________________________________________________ 21
Troubleshooting __________________________________________________________ 22
1. Power___________________________________________________________________________ 22
2. Accessories ______________________________________________________________________ 23
3. Primary Voltage Circuit ____________________________________________________________ 23
4. Low Voltage Circuit _______________________________________________________________ 24
General Reference Information_________________________________________________________ 25

Contents 3
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Required Maintenance-Normal Usage_________________________________________26
Warranty Policy_____________________________________________________________________ 27
BG770 Drawing and Parts List_______________________________________________28
BG770 Exploded View _______________________________________________________________ 28
BG770 Parts List____________________________________________________________________ 29
BG790 Drawing and Parts List_______________________________________________30
BG790 Exploded View _______________________________________________________________ 30
BG790 Parts List____________________________________________________________________ 31

4General Product Information
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General Product Information
Specifications
Specifications are for both model BG770 and model BG790 unless otherwise noted.
POWER
Line voltage is designated by third suffix of gate part
number. For amp draw, see motor nameplate.
-11; 115VAC, 1 Phase, 60Hz
-21; 230VAC, 1 Phase, 60Hz
-81; 208VAC, 1 Phase, 60Hz
-83; 208VAC, 3 Phase, 60Hz
-23; 230VAC, 3 Phase. 60Hz
-43; 460VAC, 3 Phase, 60Hz
-53; 575VAC, 3 Phase, 60Hz
MOTOR
Squirrel cage induction type (3 phase) or capacitor
start induction type (1 phase), continuous duty, 1725
RPM. Horsepower is designated by second suffix of
operator part number.
-50; 1/2 Horsepower
OVERLOAD PROTECTION
Automatic reset (3 phase operators) or manual reset
(1 phase operators) thermal overload.
ELECTRICAL BOX
NEMA 1 general purpose painted steel enclosure,
contains all motor control equipment. Enclosure
removable from operator.
CONTROL CIRCUIT
Class II, 24VAC
LIMIT SWITCHES
Adjustable, driven limit switches, operate in class II
circuit. Not affected by removal of motor.
POWER ON/OFF SWTICH
Enclosed toggle switch, HP rated.
MODEL BG770
17”
17”
Up to 12 ft.
35”44”
TYPICAL
INSTALLATION
DIMENSIONS
01-G0674F3
Figure 1
MODEL BG790
TYPICAL
INSTALLATION
DIMENSIONS
01-G0674F4
17”
17”
22”
Counterweighted
Wishbone Arm
Up to 24 ft.35”44”
Figure 2

General Product Information 5
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OPERATION
Prewired terminal strip accepts field connection of any access control device with normally open
(N.O.) output contact (most access control equipment) and when required, a separate
OPEN/CLOSE pushbutton (supplied).
Plug-in connectors are included for addition of a loop detector to open and/or a loop detector to
hold open (not supplied). Activation of access device open button, or loop detector to open will
raise gate. Gate will lower automatically unless hold open loop detector is activated or unless
CLOSE button wiring has been made, in which case gate will remain open until CLOSE button is
pushed.
An optional timer will extend the time that the gate remains open. AUTO/MANUAL switch holds
arm in vertical position.
SPEED REDUCTION
Wormgear-in-oil-bath, 60:1
ARM TYPE
MODEL BG770: One piece type to 12 feet.
MODEL BG790: Counterweighted wishbone type to 24 feet.
ARM SPEED
MODEL BG770: Opens in 4 seconds
MODEL BG790: Opens in 11 seconds
LUBRICATION
Permanently lubricated bearings in motor. Low temperature gear oil normally never needs
replacement. Gear oil is Mobil SHC 630 or equivalent.
MOUNTING
Pad mount
ENCLOSURE
Weatherproof, heavy gauge, pregalvanized steel, powdercoat finish, top and side access covers
with key lock.

6Safety Instructions
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Safety Instructions
WARNING
To reduce the risk of injury or death, it is important to read all safety instructions.
These safety instructions have been prepared by LiftMaster, the manufacturer of the barrier gate. As
the manufacturer of only part of the total barrier gate system, we do not know what type of controls or
safety equipment that has been selected as part of your system.
An automatic vehicular gate arm is a large, heavy object that moves with the help of an electric motor.
A moving gate arm can cause serious injury or death. Your safety and the safety of others
depends on you reading, understanding, and following through on the safety instructions in this
manual. It is important that both the installer and end users are aware of the hazards of your specific
system.
If you have any questions or doubts about the safety of your system, or if you do not completely
understand everything in this manual, contact LiftMaster.
Before Installation
rInstallation of this barrier gate must be done by a qualified installer.
rCheck to make sure that the available power supply to be connected to the operator is of the
same voltage, phase, frequency, and wattage as indicated on the nameplate of the operator.
rInstallation and wiring must be in compliance with local building and electrical codes.
rIt is strongly recommended that you use safety equipment with this barrier gate
operator. There are many types of safety devices available; sensing edges, photo-electric
controls, motion detectors, and vehicle detectors are some of the more common types.
Audible and/or visible warning devices are recommended when automatic controls are used in
the gate operating system.
If you need advice regarding the type of safety equipment that should be used on your
application or wish to purchase such equipment, contact the supplier of the barrier gate, or
contact LiftMaster. Without safety equipment, the gate could cause serious injury or
death.
rCarefully plan the location of barrier gate control equipment. Do not locate controls in places
where children will be able to reach or play with them. Be sure the person operating the
controls can see the full area of movement of the gate arm from the point of operation.
During Installation
rDo not place hands or fingers in or near the barrier gate unless power is off. Moving chains,
pulleys, or belts can catch clothing or fingers and cause severe injury.
rAlways disconnect power and lock out whenever installing or servicing the barrier gate.
rIf the barrier gate utilizes any automatic means of operation (such as automatic timed
closings), post warning signs that are clearly visible to persons in the area warning of the
particular hazards of the system.

Safety Instructions 7
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After Installation
rBe sure that the operator, controls, and safety devices have been tested and are functioning
properly.
rReview the operation of the gate and safety equipment with the owner or end user. Be sure
that the end user is aware of all safety instructions and hazards of the operating system.
rInform the owner or end user that the barrier gate and all control and safety equipment should
be maintained regularly. The entire gate system should be checked at least once monthly to
ensure that it is functioning properly.
With a safety edge installed, the gate must reverse on contact with a rigid object. If non-
contact sensors are connected to the Hold Open input and an object activates them, the
operator will stop a closing gate. After adjusting the force or the limit of travel, retest the gate
operator. Failure to adjust and retest the gate operator properly can increase the risk of injury
or death.
rLeave all installation manuals, instructions, and safety information, including this manual, with
the owner or end user.
rThe entrance is for vehicles only. Pedestrians must use separate entrance.
rKeep gates properly maintained. Read the owner's manual. Have a qualified service
person make repairs to gate hardware.

8Preparing the Installation
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Preparing the Installation
Unpack Carton
1Unpack the carton, checking for possible damage during shipping. The arm (when supplied) is
packed separately. Damage claims must be filed with the freight carrier.
2Check that the nameplate data (inside service cover) accurately matches the operator that
was ordered.
3Verify that the following parts are included with the standard unit.
MODEL BG770 PACKING LIST
PART NUMBER DESCRIPTION QUANTITY
02-102 OPEN/CLOSE PUSH BUTTON 1
07-8007 GATE ARM HUB 1
01-G0674 MANUAL 1
10-8007M GATE BRACKET 1
80-G0187 1/2 x 1/2 x 1-3/8L KEY 1
82-NH38-06 3/8-16 x 3/8 CONE POINT SET SCREW 2
82-HN50-25 1/2-13 x 2-1/4 HEX BOLT 4
82-RH-50 1/2-13 HEX NUT 4
85-LS-50 1/2 SPLIT LOCK WASHER 4
01-G0674 BG770 & BG790 MANUALS 1
Table 1
MODEL BG790 PACKING LIST
PART NUMBER DESCRIPTION QUANTITY
02-102 OPEN/CLOSE PUSH BUTTON 1
07-8007 ARM HUB 2
10-8055 COUNTER WEIGHT CLAMP 2
80-G0135 3/8-16 x 18 THREADED ROD 2
80-G0187 1/2 x 1/2 x 1-3/8 KEY 2
82-HN50-25 1/2-13 x 2-1/4 HEX HEAD BOLT 12
82-HN50-28 1/2-13 x 3 HEX HEAD BOLT 2
82-NH38-06 3/8-16 x 3/8 CONE POINT SET SCREW 4
84-RH-50 1/2-13 HEX NUT 14
84-WH-38 3/8-16 SERRATED FLANGE NUT 8
85-FW-38 3/8 FLATWASHER 8
85-FW-50 1/2 FLATWASHER 8
85-LS-50 1/2 SPLIT LOCK WASHER 16
01-G0674 BG770 & BG790 MANUALS 1
Table 2

Preparing the Installation 9
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Preparing the Site
1Be sure that selected gate location has required clearance for arm movement (and
counterweights on model BG790). Refer to the dimensional drawings, Figure 1and Figure 2
on page 4.
2Run electrical power to the site according to local electrical codes. See Table 3below for
correct wire size and length of run (see also Figure 3). If the wire gauge is too high (wire too
small) or the run is too long, the gate may not run properly or may not run at all. Damage to
components may result.
IMPORTANT NOTE: Be sure that the available power is the proper voltage, phase,
frequency, and amperage to supply the gate. Refer to gate nameplate located inside the
service cover.
3Select locations for control equipment and run any control wiring that may be needed (such as
loop wires, card readers, ticket spitters, pushbuttons, etc.).
WIRE SIZING CHART
SINGLE PHASE THREE PHASE
115VAC 230VAC 230 VAC 460 VAC 575VAC
AWG Maximum Length of Wire Run in Feet
6 700 3,100 4,750 14,225 35,550
8 450 1,925 3,000 8,975 22,425
10 275 1,225 1,900 5,650 14,075
12 175 775 1,175 3,525 8,825
Table 3
Note: Install Line Power Here. Do Not
Install Line Power in Panel shown below.
Power switch should be in the OFF position.
AUTO/MANUAL switch should be
in the “AUTO” position.
01-G0674F5
Figure 3

10 Preparing the Installation
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Preparing the Operator
CAUTION
Never open electrical cabinet cover unless power is off. Electrical shock and serious injury could
result.
1Remove the wood base from the unit and discard.
2Locate the keys for the access panel (taped to the arm mounting flange) and remove.
3Open the side access panel and check the position of the power ON/OFF switch.
4Open the cover of the electrical cabinet and be sure that the AUTO/MANUAL switch is in the
"AUTO" position.
5OPTIONAL CONTROL EQUIPMENT: If loop detectors, radio controls, or other control
equipment will be added at the site, do so now. Refer to the instructions in this manual for
installation of factory supplied optional open and/or hold open loop detectors, and for
connection of factory supplied optional radio controls (see Optional Accessories on page
19).