Chamberlain MGJ User manual

O W N E R ’ S M A N U A L
MODELS MGH & MGJ
MEDIUM DUTY DOOR OPERATOR
NOT FOR RESIDENTIAL USE
41B6
Serial #
(located on electrical box cover)
Installation Date
Wiring Type
www.liftmaster.com
2 YEAR WARRANTY

TABLE OF CONTENTS
CARTON INVENTORY
Carton Inventory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Operator Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Operator Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
PREPARATION
MGJ Opposite Handing Preparation . . . . . . . . . . . . . . . . . . . . . . 5
MGH Left Hand Mounting Preparations . . . . . . . . . . . . . . . . . . . 6
INSTALLATION
Mount the Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Manual Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Entrapment Protection Accessories (Optional) . . . . . . . . . . . . . . 8
ADJUSTMENT
Limit Switch Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
POWER WIRING & GROUND WIRING
Power Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Ground Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
CONTROL WIRING & INSTALLATION
Determine Wiring Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Model MGJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Special Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Mounting Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
DIAGRAMS
Single Phase Schematic Diagram for MGJ/MGH . . . . . . . . . . . 12
Three Phase Schematic Diagram for MGJ Only . . . . . . . . . . . . 13
MAINTENANCE
Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
How to Order Repair Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
REPAIR PARTS
MGH Illustrated Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Replacement Part Kits MGH . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
MGJ/MGH Electrical Box - Illustrated Parts . . . . . . . . . . . . . . . 18
Electrical Box - Models MGJ & MGH . . . . . . . . . . . . . . . . . . . . 19
Illustrated Parts - Model MGJ. . . . . . . . . . . . . . . . . . . . . . . . . . 20
Replacement Part Kits MGJ . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Operator Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-23
Control Connection Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . 24
When you see these Safety Symbols and Signal Words on the
following pages, they will alert you to the possibility of serious
injury or death if you do not comply with the warnings that
accompany them. The hazard may come from something
mechanical or from electric shock. Read the warnings carefully.
When you see this Signal Word on the following pages, it will
alert you to the possibility of damage to your door and/or the
door operator if you do not comply with the cautionary
statements that accompany it. Read them carefully.
Mechanical
Electrical
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNINGWARNING
CAUTION
WARNING
WARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNINGWARNING
WARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTIONCAUTION
WARNING
WARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
IMPORTANT NOTES:
• BEFORE attempting to install, operate or maintain the operator,
you must read and fully understand this manual and follow all
safety instructions.
• DO NOT attempt repair or service of your commercial door and
gate operator unless you are an Authorized Service Technician.
2

WEIGHTS AND DIMENSIONS - MGH
HANGING WEIGHT: 70-80 LBS.
WEIGHTS AND DIMENSIONS - MGJ
HANGING WEIGHT: 50-60 LBS.
CARTON INVENTORY
Before beginning your installation check that all components were provided.
DESCRIPTION
POWERHEAD ASSEMBLY
OWNER’S MANUAL AND CAUTION LABELS
HARDWARE BOX
3-BUTTON CONTROL STATION
HOIST HAND CHAIN (MGH Model only)
DOOR SPROCKET
DOOR/OPERATOR DRIVE CHAIN
OPERATOR DIMENSIONS
7.50" (19.05 cm)
7.00"
(17.78 cm)
9.25"
(23.50 cm)
Mounting Dimensions
Mounting Dimensions
11.05" (28.07 cm)
3.00"
(7.62 cm)
11.00"
(27.94 cm)
10.50" (26.67 cm)
5.50" (13.97 cm)
4.75"
(12.07 cm)
18.00"
(45.72 cm)
11.25"
(28.58 cm)
2.99"
(7.59 cm)
13.28"
(33.73 cm)
1.96"
(4.98 cm)
.98"
(2.49 cm)
2.25"
(5.72 cm)
4.50"
(11.43 cm)
3

MOTOR
TYPE: . . . . . . . . . . . . . . . . . . .Limited Duty
HORSEPOWER: . . . . . . . . . . .MGJ: 1/2 HP 1 or 3 Phase
MGJ: 3/4 HP 1 Phase (only)
MGH: 1/2 & 3/4Hp 1 Phase
VOLTAGE: . . . . . . . . . . . . . . . .MGJ: 120V, 60Hz, 1Ph
230V, 50 or 60Hz, 3Ph
230V, 60Hz, 1Ph
380V, 50Hz, 3Ph
460V, 60Hz, 3Ph
MGH: 120V, 60Hz, 1Ph
CURRENT: See motor nameplate
The rate of operation shall not exceed 12 cycles of opening
and closing per hour.
MECHANICAL
DRIVE REDUCTION: . . . . . . . . . . . 45:1 Reduction
(Heavy duty wormgear-in-oil-bath speed reducer)
OUTPUT SPROCKET: . . . . . . . . . . Size #41
OUTPUT SHAFT SPEED:. . . . . . . . MGJ: 1Ph, 23RPM
3Ph, 39RPM
. . . . . . . . . . . . . . . . . . . . . . . . . . . MGH: 1Ph, 23RPM
BEARINGS: . . . . . . . . . . . . . . . . . . Heavy duty wormgear-in-oil-
bath speed reducer.
DUTY: . . . . . . . . . . . . . . . . . . . . . . 12 Cycles per Hour max
50 Cycles per Day max
DOOR SPEED:. . . . . . . . . . . . . . . . 9" per second, typical,
depending on door.
MAX. DOOR HEIGHT: . . . . . . . . . . 1/2 HP = 14'
3/4 HP = 18'
SAFETY
DISCONNECT:. . . . . . . . . . . . . . . . . . . . Floor level disconnect for
emergency manual door operation.
REVERSING EDGE (Optional): . . . . . . . Electric or
pneumatic sensing device attached to the bottom edge of door
A REVERSING EDGE IS STRONGLY RECOMMENDED FOR ALL
COMMERCIAL OPERATOR INSTALLATIONS. REQUIRED WHEN
THE 3 BUTTON CONTROL STATION IS OUT OF SIGHT OF DOOR
OR ANY OTHER CONTROL (AUTOMATIC OR MANUAL) IS USED.
ELECTRICAL
TRANSFORMER:. . . . . . . . . . 24VAC
CONTROL STATION:. . . . . . . NEMA 1 three button station.
OPEN/CLOSE/STOP
WIRING TYPE: . . . . . . . . . . . MGH/MGJ: C2 (factory default), B2
optional
LIMIT ADJUST:. . . . . . . . . . . Linear driven, fully adjustable
screw type cams. Adjustable to
18 feet.
OPERATOR SPECIFICATIONS
4

Shipped from the factory for either left hand or right hand
mounting. Refer to the last digit in the model number for handing
of your unit. If necessary, the operators may also be field modified
to accommodate opposite handing.
MGJ OPPOSITE HANDING PREPARATIONS
REMOVE DISCONNECT ASSEMBLY COMPONENTS
Remove the master link from the limit chain, remove the chain
and set it aside. Remove the two e-rings securing the sprocket on
the gear reducer shaft. Remove the screws securing the yoke to
the disconnect shaft, set the yoke aside.
Remove the three cotter pins from the disconnect shaft. Do not
discard the pins. Slide the disconnect shaft out of the support
bracket. The release lever will now be free inside the motor frame.
Remove the release lever and sash chain from the motor frame.
Slide the disconnect hub, compression spring, and flatwasher
from the end of the gear reducer shaft. Remove the disconnect
support bracket by first removing the two gear reducer housing
screws. Replace the screws in the gear reducer and firmly tighten.
RE-ASSEMBLE DISCONNECT ASSEMBLY
Remove the two screws on the opposite side of the gear reducer
and mount the disconnect support bracket with the notched side
facing the motor. For the remainder of the installation, follow the
steps outlined above in reverse order, referring to the illustration
as necessary.
Keys
Spring
Disc Hub
Sprocket
E-Ring
Bracket
Yoke
Shaft
Disc Lever
PREPARATION
To prevent possible SERIOUS INJURY or DEATH:
• DO NOT connect electric power until instructed to do so.
• If the door lock needs to remain functional, install an
interlock switch.
• ALWAYS call a trained professional door serviceman if door
binds, sticks or is out of balance. An unbalanced door may
not reverse when required.
• NEVER try to loosen, move or adjust doors, door springs,
cables, pulleys, brackets or their hardware, ALL of which are
under EXTREME tension and can cause SERIOUS
PERSONAL INJURY.
• Disable ALL locks and remove ALL ropes connected to door
BEFORE installing and operating door operator to avoid
entanglement.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNING
WARNINGWARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
REMOVE LIMIT SWITCH SHAFT ASSEMBLY
Remove limit chain. Remove the e-ring and washers from the side
away from the limit chain sprocket. Remove limit shaft. The limit
adjust nuts will need to be unscrewed while removing shaft. To
reassemble follow the above steps in reverse order.
5

HAND CHAIN RIGHT/LEFT CONVERSION
1. Remove snap ring from end of shaft on the hoist side.
2. Remove the washers, chain guide and chain wheel.
3. Remove drive pin from shaft and relocate to the opposite
side.
4. Install chain wheel, chain guide, washers and snap ring.
MGH LEFT HAND MOUNTING PREPARATIONS
The operator may be mounted on either the right (standard) or left
side of door, and in either a vertical (standard) or horizontal
mounting position. Refer to the steps below if you require the
hand chain and/or disconnect chain to be on the opposite side of
the operator; or if the operator is being mounted in a horizontal
position.
DISCONNECT LEVER RIGHT/LEFT CONVERSION
1. Remove cotterpins on the ends of the disconnect shaft
(square shaft).
2. Move the disconnect lever arm and the washer to the
opposite sides.
3. Replace the cotterpins.
PREPARATION
HORIZONTAL MOUNTING CONVERSION
1. Remove cotterpin on the ends of the disconnect shaft
(square shaft).
2. Remove lever and turn 90 degrees so that the lever is pointing
away from the motor. The lever will be directly under the
hoist shaft.
3. Replace cotterpin.
Chain GuideHand
Hand Chain Wheel
Cutout for Roll Pin
(typical both sides)
Disconnect Lever
Cotterpin
6

FIGURE 2
FIGURE 1
IMPORTANT NOTE: Before your operator is installed, be sure the
door has been properly aligned and is working smoothly. The
operator may be wall mounted or mounted on a bracket or shelf.
If necessary, refer to the preparation on page 5. Refer to the
illustration and instructions below that suits your application.
OPTIONAL
Mounting Bracket
P/N 089098
INSTALLATION
MOUNT THE OPERATOR
1. Wall Mount: The operator should generally be installed below
the door shaft, and as close to the door as possible (Figure1).
Bracket Shelf Mounting: The operator may be mounted
either above or below the door shaft (Figure 2).
IMPORTANT: The shelf or bracket must provide adequate
support, prevent play between operator and door shaft, and
permit operator to be fastened securely and with the drive shaft
parallel to the door shaft.
NOTE: The optimum distance between the door shaft and
operator drive shaft is between 12-15" (30.5-38.1 cm).
2. Place door sprocket on the door shaft. Do not insert the key
at this time.
3. Place drive sprocket on the appropriate side of the operator.
Do not insert the key at this time.
4. Wrap drive chain around door sprocket and join roller chain
ends together with master link.
5. Raise operator to approximate mounting position and
position chain over operator sprocket.
6. Raise or lower operator until the chain is taut (not tight).
Make sure the operator output shaft is parallel to door shaft
and sprockets are aligned. When in position, secure the
operator to wall or mounting bracket.
7. Align sprockets and secure (Figure 3).
8. Install Hand Chain (Model MGH only)
Place hand chain around hand chain wheel. Be sure to pass it
through both openings in the chain guide. Remove enough
links so chain hangs approximately 2' (.61 m) above the
floor.
9. Mount Chain Keeper / Keyhole Bracket
Using suitable hardware mount the chain keeper
approximately 4' (1.22 m) above the floor, near the free
hanging chain. Remove disconnect sash chain from bag and
place the end through the keyhole in the chain keeper.
Remove excess links if necessary.
Typical Right Hand
Wall Mounted Operator
FIGURE 3
Be sure door sprocket is
properly aligned with drive
before securing to
the shaft.
7

MANUAL OPERATION
This operator is equipped with a floor level disconnect chain to
allow for manual operation of the door in case of emergency or
power failure.
MODEL MGJ
1. To disengage, pull the sash chain and secure in the disengaged
position by slipping the end through the keyhole bracket
mounted on the wall. Or if emergency egress device is used,
pull handle to disengage operator from door.
2. The door may now be pushed up or pulled down manually or if
equipped with manual hand chain hoist (model MGH only),
door can be raised or lowered with hand chain. Release the
disconnect chain to operate the door again electrically.
MODEL MGH
1. Pull the disconnect chain (small chain) to engage the interlock
to disable the controls. The disconnect chain may be locked in
position by slipping the end through the keyhole of the chain
keeper mounted on the wall.
2. Operate the door in the desired direction by pulling on one side
or the other of the continuous loop hoist chain (large chain).
3. The disconnect chain must be released from the chain keeper
before the door will operate again electrically.
INSTALLATION
To prevent possible SERIOUS INJURY from a moving chain,
DISCONNECT electric power to the operator BEFORE manually
operating your door.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNINGWARNING
CAUTION
WARNING
WARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
Chain Keeper (with pad
locking provisions)
ENTRAPMENT PROTECTION ACCESSORIES
(OPTIONAL)
SENSING EDGES
All types of sensing edges with an isolated normally open (N.O.)
output are compatible with your operator. This includes
pneumatic and electric edges. If your door does not have a
bottom sensing edge and you wish to purchase one, contact the
supplier of your operator.
If not pre-installed by the door manufacturer, mount the sensing
edge on the door according to the instructions provided with the
edge. The sensing edge may be electrically connected by either
coiled cord or take-up reel. Refer to the steps below.
IMPORTANT NOTES:
a. Proceed with Limit Switch Adjustments described below before
making any sensing edge wiring connections to operator.
b. Electrician must hard wire the junction box to the operator
electrical box in accordance with local codes.
TAKE-UP REEL
Take-up reel should be installed 12" (30.48 cm) above the top of
the door.
COIL CORD
Connect operator end of coil cord to junction box (not provided)
fastened to the wall approximately halfway up the door opening.
To reduce the risk of SEVERE INJURY or DEATH, ALWAYS
install reversing sensors when the 3-button control station is
out of sight of door or ANY other control (automatic or
manual) is used. Reversing devices are recommended for ALL
installations.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNINGWARNING
CAUTION
WARNING
WARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
Keyhole Bracket
MGJ
MGH
8

LIMIT SWITCH ADJUSTMENT
NOTE: Make sure the limit nuts are positioned between the limit
switches before proceeding with adjustments.
1. Depress retaining plate to allow nut to spin freely. After
adjustment, release plate and move nut back and forth to
ensure it is fully seated in slot.
2. To increase door travel, spin nut away from limit switch. To
decrease door travel, spin limit nut toward limit switch.
3. Adjust open limit nut so that door will stop in open position
with the bottom of the door even with top of door opening.
4. Repeat steps 1 and 2 for close cycle. Adjust close limit nut so
that the limit switch is engaged as door fully seats at the floor.
OPEN Limit Switch
Actuator
Retaining Plate
(Aux. Open) Limit Switch
SAFETY
(Aux. Close) Limit Switch
CLOSE Limit Switch
ADJUSTMENT
To avoid SERIOUS PERSONAL INJURY or DEATH from
electrocution, disconnect electric power BEFORE manually
moving limit nuts.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNING
WARNINGWARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
9

POWER WIRING & GROUND WIRING
To reduce the risk of SEVERE INJURY or DEATH:
• ANY maintenance to the operator or in the area near the
operator MUST NOT be performed until disconnecting the
electrical power and locking-out the power via the operator
power switch. Upon completion of maintenance the area
MUST be cleared and secured, at that time the unit may be
returned to service.
• Disconnect power at the fuse box BEFORE proceeding.
Operator MUST be properly grounded and connected in
accordance with local electrical codes. The operator should be
on a separate fused line of adequate capacity.
• ALL electrical connections MUST be made by a qualified
individual.
• DO NOT install ANY wiring or attempt to run the operator
without consulting the wiring diagram. We recommend that
you install an optional reversing edge BEFORE proceeding
with the control station installation.
• ALL power wiring should be on a dedicated circuit and well
protected. The location of the power disconnect should be
visible and clearly labeled.
• ALL power and control wiring MUST be run in separate
conduit.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNING
WARNINGWARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
POWER WIRING CONNECTIONS
1. Connect power wires coming from the main to the captive
terminal block in the electrical box enclosure marked with the
label. All power and control wiring must be run in separate
conduit in accordance with local electrical codes.
2. Be sure to run all power wires through the conduit hole in the
electrical box enclosure marked with the label shown below.
NOTE: Must use #14 AWG or thicker wire for power wiring.
ON THREE PHASE MACHINES ONLY: Incorrect phasing of the
power supply will cause the motor to rotate in the wrong
direction. To change motor rotation, exchange incoming power
leads L1 and L2.
GROUND WIRING CONNECTIONS
1. Connect earth ground to the chassis ground screw in the
electrical box enclosure.
2. Use same conduit entry into the electrical box as the power
wiring.
IMPORTANT NOTE: This unit must be properly grounded. Failure
to properly ground this unit could result in electric shock and
serious injury.
Single Phase Power Wiring
Three Phase Power Wiring
Neutral
Hot Gnd
L2L112111074321
Phase 1 Gnd
L2L112111074321 L3
Phase 2
Phase 3
10

DETERMINE WIRING TYPE
Refer to the wiring diagram located on the inside cover the
electrical box to determine the type of control wiring.
STANDARD C2 OR B2 WIRING
Operators are shipped from the factory with jumper set for C2
wiring, which requires constant pressure on button to close the
door. If momentary contact in close direction is desired (B2
wiring) you must include an entrapment protection device. See
close control jumper setting below.
Constant pressure on close (C2 wiring)
Red jumper wire was placed on terminal #2 in the electrical
enclosure. The operator will require constant pressure on close
control in order to keep door moving in the close direction.
Momentary contact on close (B2 wiring)
Move red jumper wire from terminal #2 to terminal #3. The
operator will require only momentary contact to close the door.
SPECIAL CONTROL WIRING
If your operator was shipped from the factory with non-standard
control wiring or with optional accessories that require additional
instructions, refer to the wiring diagram(s) indicated in the
special control wiring data box. When a replacement wiring
diagram is present, wiring diagrams in this manual will not apply.
Refer only to the replacement wiring diagram for all connections.
IMPORTANT NOTE: If your wiring diagram is missing, or you are
unsure of the wiring type for your operator, contact the customer
service department @ 1-800-528-2806.
MOUNTING INSTRUCTIONS
All operators are supplied with some type of control station.
Generally a 3-button station (OPEN/CLOSE/STOP) is provided. A
two-position key switch or control station (OPEN/CLOSE) may be
added or substituted when requested at the time of order.
1. Mount WARNING NOTICE beside or below the control station.
2. Mount control station(s) within line of sight of door(s).
CONTROL WIRING & INSTALLATION
To reduce the risk of SEVERE INJURY or DEATH:
• ANY maintenance to the operator or in the area near the
operator MUST NOT be performed until disconnecting the
electrical power and locking-out the power via the operator
power switch. Upon completion of maintenance the area
MUST be cleared and secured, at that time the unit may be
returned to service.
• Disconnect power at the fuse box BEFORE proceeding.
Operator MUST be properly grounded and connected in
accordance with local electrical codes. The operator should be
on a separate fused line of adequate capacity.
• ALL electrical connections MUST be made by a qualified
individual.
• DO NOT install ANY wiring or attempt to run the operator
without consulting the wiring diagram. We recommend that
you install an optional reversing edge BEFORE proceeding
with the control station installation.
• ALL power wiring should be on a dedicated circuit and well
protected. The location of the power disconnect should be
visible and clearly labeled.
• ALL power and control wiring MUST be run in separate
conduit.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNING
WARNINGWARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
WARNINGWARNING
TO PREVENT ENTRAPMENT
DO NOT START DOOR DOWNWARD
UNLESS DOORWAY IS CLEAR
4'
Approximate
Control
Station
11

CLOSE-A
* TO REVERSE MOTOR ROTATION, INTERCHANGE
RED AND YELLOW MOTOR WIRES.
OPEN/CLOSE
CLOSE
SAFETY
EDGE
OPEN
BR
2
P
7Y
10
GY
Y
AUX.
CLOSE L/S
R1 BR
1
OR
GY
AUX.
OPEN
L/S
OPEN-B
BL
OR
12
BL
C
BK
3
STOP
L2 BK
CLOSE-B
4
R
OPEN-A
W
C
CAPACITOR
Y
N.O.
BL
OPEN L.S.
CLOSE L/S
PP
CL
OR
R
N.O.
R
OR
OP N.C. C
W
W
W
11
BR
L1
MOTOR *
R
Y
10VA.
PR1.
24VAC.
SEC.
Y
W
O/L BK
WIRE NUT
R3
R2
N.C. C
MOVE JUMPER WIRE TO
TERMINAL #2 FOR MOMENTARY
CONTACT ON CLOSE
Y
HAND CHAIN
INTERLOCK SW.
(WHEN PRESENT)
RES.
SINGLE PHASE SCHEMATIC DIAGRAM FOR MGJ/MGH
12

4356
12
43
21
65
L3
L2
(GY)
(PUR)
(YEL)
EXTERNAL
STOP
354 T1
24VAC
SEC.
PRI.
AUX. CLOSE
LIMIT SWITCH
NC C
1
7
10
OPEN
SAFETY EDGE
OPEN & CLOSE
LIMIT SWITCH
AUX. OPEN
C
NO
NC
LIMIT SWITCH
NC C
TO MOTOR
POWER IN
L1
3 PHASE
INTERLOCK
OP
R1
OP
OP
CL
CL OP
CL
OP
14
13
(IN MOTOR)
R1
OPEN & CLOSE
R2
R1
OPEN
CLOSE 2
14
13
CL
CL
LIMIT SWITCH
NC
CLOSE
C
R1
(BK)
(BK)
(BK)
(BRN)
(BR)
(YEL)
(OR) (OR) (OR) (OR)
(RED) (RED)
(OR)
(YEL)
(YEL)
(PUR)
(OR)
(PUR) (PUR) (PUR) (PUR)
(PUR)
R3 (RED)
(BRN)
(YEL)
(OR)
(OR)
(SEE NOTE #1)
(RED)
(WHEN PRESENT)
230V BRAKE
(GY)
(GY)
RADIO TO
A1 A2
A2 A1
(YEL)
NUT
WIRE
2
3
YEL
BRN
BRN
PUR
GY 1
6
9
BL/BK
BL/BK
O/L
4
7
85
(WHEN PRESENT)
230V BRAKE
2
3
YEL
BRN
BRN
PUR
GY 1
6
9
BL/BK
BL/BK
O/L
4
7
85
230 VOLT - 3 PHASE
MOTOR CONNECTION
460 VOLT - 3 PHASE
MOTOR CONNECTION
**
NOTE: Voltage same as line voltage.
(BK) (BK)
OVERLOAD
(RED)
C2 WIRING - Constant Presssure to Close
RED WIRE ON TERMINAL #2 (Shipped from Factory)
B2 WIRING - Momentary Contact to Close
MOVE RED WIRE FROM TERMINAL #2 TO TERMINAL #3
*
CLOSE CONTROL WIRING OPTIONS
- Shipped from Factory
*
THREE PHASE SCHEMATIC DIAGRAM FOR MGJ ONLY
13

6Use SAE 30 Oil (Never use grease or silicone spray).
Repeat ALL procedures.
Do not lubricate motor. Motor bearings are rated for
continuous operation.
Inspect and service whenever a malfunction is
observed or suspected.
CAUTION: BEFORE SERVICING, ALWAYS
DISCONNECT OPERATOR FROM POWER SUPPLY.
MAINTENANCE SCHEDULE
Check at the intervals listed in the following chart:
HOW TO ORDER REPAIR PARTS
OUR LARGE SERVICE ORGANIZATION SPANS AMERICA
Installation and service information are available.
Call our TOLL FREE number:
1-800-528-2806
www.liftmaster.com
MAINTENANCE
To avoid SERIOUS PERSONAL INJURY or DEATH from
electrocution, disconnect ALL electric power BEFORE
performing ANY maintenance.
ATTENTION
AVERTISSEMENT AVERTISSEMENT
AVERTISSEMENT
WARNING
CAUTION
WARNING
WARNINGWARNING
PRECAUCIÓN ADVERTENCIA
ADVERTENCIAADVERTENCIA
ITEM
Drive Chain
Sprockets
Fasteners
Manual Disconnect
Bearing & Shafts
PROCEDURE
Check for excessive slack.
Check & adjust as required.
Lubricate. *
Check set screw tightness
Check and tighten as required
Check & Operate
Check for wear & lubricate
EVERY
3MONTHS
z
z
z
EVERY
6MONTHS
z
z
EVERY
12 MONTHS





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K3 (K75-12829)
K2 (K72-12789)
K1 (K75-12783)
2
4
1
5
3
9
6
7
8
10
11
MGH ILLUSTRATED PARTS
16

REPLACEMENT PART KITS MGH
Refer to the parts lists below for replacement kits available for your operator. If optional modifications and/or accessories are included
with your operator, certain components may be added or removed from these lists.
SERVICE KITS
Item Part # Description
1 K20-1050C-1M-1 1/2 HP Motor
K20-1075C-1M 3/4 HP Motor
2 32-34291 Gear reducer
3 23-10916 Switch assembly interlock
4 15-41B19LKGFO Sprocket
5 15-48B19LKGEO Sprocket
6 75-10884 Chain assembly wheel
7 10-10882 Hand chain guide
8 08-11013 Gear
9 08-11012 Bevel gear
10 K10-34319 Gear housing cover
11 (see page 19) Complete electrical box
Item Part # Description
K1 K75-12783 Disconnect assembly
Complete with: Bevel gear yoke,
disconnect release lever, retaining
plate, disconnect shaft sprocket,
compression spring, key, screws,
flatwasher, cotter pin, roll pin
and e-ring.
K2 K72-12789 Hand chain shaft kit (1/2 thru 2 HP)
Complete with: Bevel gear 5/8" ID,
bevel gear 3/4" ID, hand chain
guide, hand chain shaft, bearing 3/4"
ID, nyliner bearing, compression
spring, chain wheel, washers, roll
pins and e-rings.
K3 K75-12829 Gear housing kit
(Includes all parts from K2)
Complete with: Housing support
bracket, pads and pressure plate,
housing with cover, disconnect kit,
hand chain shaft and brake kit.
INDIVIDUAL PARTS
17

3
K1 (K75-12567)
6
8
3
1
1
9
5
7
9
4
2
MGJ/MGH ELECTRICAL BOX - ILLUSTRATED PARTS
18

ELECTRICAL BOX- MODELS MGJ & MGH
For replacement of electrical box, motor or brake components be sure to match model number of your unit to kit number below to
ensure proper voltage requirements.
NOTE: Reversing Contactor (03-8024-K), used only on three
phase operators. Single phase operators use relays.
INDIVIDUAL PARTS
ITEM PART # DESCRIPTION
1 13-10024 Limit nut
2 10-11403 Electrical box cover
3 03-11112 Reversing contactor (See note)
4 21-5115 Transformer, 115V
21-5230 Transformer, 230V
21-5460 Transformer, 460V
5 24-24-1 Relay, 24V DPDT
6 29-10338 Capacitor - 1/2 HP 70 MFD
with bracket
30B652 Capacitor - 3/4 HP 89 MFD
with screw
7 29-2 Resistor, 200hm
8 15-58B07AXX Sprocket 48B07
9 23-10041 Limit switch SPDT
SERVICE KITS
ITEM PART # DESCRIPTION
K1 K72-12565 Limit shaft assembly
Complete with: Limit shaft, limit nuts,
plastic flange bearing, limit sprocket,
washer, flatwashers, roll pin,
and e-ring.
K2 K72-12566 Limit shaft assembly
Complete with: Depress plate, depress
spring plate, limit switches, spacers,
screws, nuts, and locknuts.
• To order a complete electrical box kit, add a K- prefix to the
model number of your operator. For example:
T5011L3 (Operator) = K-T5011L3 (Electrical box kit).
19

4
5
1
3
2
K1 K75-12567
ILLUSTRATED PARTS - MODEL MGJ
20