Lift-master MT User Manual

2 YEAR WARRANTY

Serial #

(located on electrical box cover)

Installation Date

Wiring Type

OWNER'S MANUAL

MODEL MT

MEDIUM DUTY DOOR OPERATOR

NOT FOR RESIDENTIAL USE

LISTED DOOR OPERATOR

41B6

FACTORY SET

C2 Wiring

See page 8 for

other wiring

configurations

SPECIFICATIONS

MOTOR

TYPE: .................................Intermittent duty

HORSEPOWER: ................1/2 Horsepower

SPEED:...............................1000 RPM

VOLTAGE: .........................115V, 1 Phase, 60Hz

230V, 1 Phase, 50Hz

CURRENT: .........................See motor nameplate

MECHANICAL

DRIVE REDUCTION:.............Primary: Heavy duty

(4L) V-Belt. Secondary: #48 chain/sprocket. Output:

#48 chain

OUTPUT SHAFT SPEED:.....108 R.P.M.

DOOR SPEED:......................approx. 9” per sec.

depending on door

BRAKE (Optional): ...............Solenoid actuated disc

brake

BEARINGS:...........................IronCopper sintered and

oil impregnated.

ELECTRICAL

TRANSFORMER:.............24VAC

CONTROL STATION: .....NEMA 1 three button station.

OPEN/CLOSE/STOP

WIRING TYPE:.................C2 (Factory Shipped)

Momentary contact to OPEN & STOP, constant
pressure to CLOSE, plus wiring for sensing device to
reverse. See page 8 for control wiring options.

LIMIT ADJUST:................Linear driven, fully

adjustable screw type cams.

SAFETY

DISCONNECT:.............Quick disconnect door arm for

emergency manual door operation.

SENSING DEVICE: ......Accepts photo electric controls

such as CPS, or an electric / pneumatic sensing edge
can be attached to the bottom edge of door.

A SENSING DEVICE IS STRONGLY

ALL

RECOMMENDED FOR
OPERATOR INSTALLATIONS.
THE 3 BUTTON CONTROL STATION IS OUT OF
SIGHT OF DOOR OR ANY OTHER CONTROL
(AUTOMATIC OR MANUAL) IS USED.

COMMERCIAL

REQUIRED

WHEN

WEIGHTS AND DIMENSIONS

HANGING WEIGHT:.........80-110 LBS.

12-1/2”

9-1/2”

16-3/16”

Door Height Plus 4 feet (minimum)

4”

PATH OF HIGHEST POINT ON DOOR

2

WARNING

WARNING

PREPARATION

3. Align the track so that the bolts inserted in step 2
line up with the L-Slots in the frame.

KEEP DOOR BALANCED. STICKING OR BINDING
DOORS MUST BE REPAIRED. DOORS, DOOR
SPRINGS, CABLES, PULLEYS, BRACKETS AND
THEIR HARDWARE MAY BE UNDER EXTREME
TENSION AND CAN CAUSE SERIOUS PERSONAL
INJURY OR DEATH. CALL A PROFESSIONAL DOOR
SERVICEMAN TO MOVE OR ADJUST DOOR
SPRINGS OR HARDWARE.

TRACK ASSEMBLY

1. Using the 3/8"-16 x 3/4 " bolts and flange hex
nuts supplied, assemble the operator track by
installing and tightening the track spacer brackets.
Position the spacers evenly over the length of the
track. NOTE: The nylon pad on the spacer bracket
should face up.

2. Using (2) 3/8"-16 x 1" bolts and lock washers,
install the front idler assembly to the second set of
holes of one end of the track. Refer to the illustration
below.

3. Slide the trolley carriage onto the track so that
the take-up bolt will be toward the operator.

4. Connect the track to the powerhead by fastening
two 3/8"-16 x 3/4" bolts and nuts through the frame
and the end holes in track. Tighten all four bolts to
secure the track to the powerhead.

TROLLEY CARRIAGE / CHAIN ATTACHMENT

1. Attach the take-up bolt to the trolley carriage using
3/8-16 hex nuts and lock washer, as shown below.

2. Using one of the master links, attach the chain to
the other end of the trolley carriage. Reel the chain
around the front idler shaft, over the spacer brackets,
back to the drive shaft sprocket, and then to the take­up bolt on the carriage.

3. Using the other master link, attach the chain to the
take-up bolt and tighten to the desired chain tension.

Chain Tension: With trolley positioned at either end
of the track, a properly adjusted chain will sag about 3"
at the mid-point. If necessary, remove links from the
chain to achieve proper adjustment.

POWERHEAD ATTACHMENT

1. Position the track assembly on the frame of the
powerhead so that the motor side of operator is in
back (away from door ).

2. Loosely install two 3/8"-16 x 3/4" bolts and nuts in
third hole from the end of the track .

TROLLEY CARRIAGE

SPACER BRACKET

(Mounted Nylon Pad Side Up)

L - SLOT

Take-Up Bolt

FRONT IDLER ASSEMBLY

TROLLEY ASSEMBLY

Hex Nut

Lockwasher

Reel Chain
around Idler and
over Spacer Brackets

Master Link

Trolley Carriage

Takeup Bolt

Hex
Nut

Master Link

Roller Chain

3

Straight Arm

INSTALLATION INSTRUCTIONS

Carpenter's

Level

Header

Wall

High Arc

Point

IMPORTANT NOTE: Before the operator is installed, be sure the door has been properly aligned and is working
smoothly. Although each installation will vary due to par ticular building characteristics, refer to the following gen­eral procedures to install the operator.

MOUNT HEADER BRACKET

The trolley operator is generally mounted over the
center of the door. However, off center mounting may
be required due to interfering structures or location of
door stile / top section support. In such cases, the
operator may be mounted up to 24” off center on tor­sion spring doors. Extension springs require center
mounting.

1. Locate the center of the door and mark a line on
the wall directly above the door. Extend this line up
the wall.

2. Determine the highest point of door travel. Slowly
raise the door and observe the action of the top sec­tion. When the top section reaches its highest point,
use a level and project a line from this point to the
center line the of the door.

MOUNT OPERATOR

1. Allowing the motor to rest on the floor, raise the
front end of the track assembly to the front header
bracket and fasten using the 3/8”dia.x 6.40” long pivot
shaft and cotterpins supplied.

Header Attachment

Cotterpins

Pivot shaft

Door Tra v el
Projection

3. Using the projected lines for location, mount a
suitable wood block or length of angle iron to the wall
above the door opening. Refer to the illustration
below. This will provide a mounting pad for the front
header bracket of the operator. If necessary reinforce
the wall with suitable mounting brackets to ensure
adequate support of mounting pad. Using suitable
hardware, mount the (U shaped) front header bracket
to the pad.

3.50”

1.75”

4” MIN.

High Rise Point
Projection Line

2. Swing the operator to a horizontal position above
the guide rails and temporarily secure with a suitable
rope, chain, or support from the floor. Now open
garage door slowly, being careful not to dislodge the
temporary support. Using the door as a support,
place a level against the rail and shim the operator
until it is horizontal. Make sure that the operator is
aligned with the center line of the door.

Guide
Rails

Using the Door as support, shim
operator to a horizontal position.

OF DOOR

Header Bracket Drill Pattern

Operator Alignment

4

INSTALLATION INSTRUCTIONS

WARNING

OPERATOR SUPPORT

1. The illustration below shows a typical method of
hanging the operator from the ceiling. Each
installation may vary, but in all cases side braces
should be used for additional strength.

2. For mounting of the support brace(s) to the
powerhead, Four holes (clearance up to 3/8” bolts)
are located on each side of frame.

NOTE: If the operator is longer than 15 feet, use of a
mid-span support is recommended.

WARNING

FAILURE TO SUSPEND THE OPERATOR
SECURELY MAY RESULT IN SERIOUS PERSONAL
INJURY OR DEATH, AND/OR PROPERTY DAMAGE.

STRAIGHT ARM ATTACHMENT

1. Fully close the door and move the trolley slider to
within (2”) two inches of the front idler.

2. Latch the straight door arm to the fixed roll pin in
the trolley carriage. Make sure the open side of
notch on the arm faces the doorway.

3. Attach the door bracket to the door arm using the
3/8”-16 x 1” bolt and nylon locking nut provided.
Leave the nut and bolt loose enough to allow the two
pieces to pivot freely.

4. Using 3/8” hardware provided, bolt the curved
door arm to the straight arm, aligning the mounting
holes in such a way that the door bracket pivot bolt
will be in line with the top rollers on the door.

5. Position the door bracket to the center line on the
door. Using suitable hardware, attach the door
bracket to the door. Many installations, except solid
wood doors, will require additional support for the
door. Refer to the illustration below.

IMPORTANT NOTE: At this time, ensure all bolts
and lag screws are properly secured.

Top
Roller

Mid-Span
Support Brace

Powerhead Support Brace

Straight Arm

Center Line of Door

Door Bracket

Curved
Door Arm

Pivot Bolt

5

WARNING

ENTRAPMENT PROTECTION ACCESSORIES (OPTIONAL)

WARNING

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 before

making any sensing edge wiring connections to
operator as described below.

b) Electrician must hardwire the junction box to the

operator electrical box in accordance with local
codes.

WARNING

THIS OPERATOR CONTAINS AN AUTO­REVERSE CIRCUIT THAT REQUIRES PROPER
CLUTCH ADJUSTMENT IN ORDER TO
FUNCTION. AN IMPROPERLY ADJUSTED
CLUTCH MAY REDUCE THE LIFE OF THE
OPERATOR OR ITS COMPONENTS.

The Auto-Reverse circuit is NOT intended and
may not be used as an entrapment protection
device. A safety reversing edge or infrared
sensor should be added to door if necessary.

TAKE-UP REEL: Take-up reel should be installed

12" above the top of the door.

COIL CORD: Connect operator end of coil cord to
junction box (not supplied) fastened to the wall
approximately halfway up the door opening.

LIMIT SWITCH ADJUSTMENT

MAKE SURE THE LIMIT NUTS ARE POSITIONED BETWEEN THE LIMIT SWITCH ACTUATORS BEFORE
PROCEEDING WITH ADJUSTMENTS.

1. To adjust limit nuts depress retaining plate to allow
nut to spin freely. After adjustment, release plate
and ensure it seats fully in slots of both nuts.

2. To increase door travel, spin nut away from
actuator. To decrease door travel, spin limit nut
toward actuator.

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 actuator is engaged as door fully
seats at the floor.

TO AVOID SERIOUS PERSONAL INJURY OR DEATH
FROM ELECTROCUTION, DISCONNECT ELECTRIC
POWER BEFORE MANUALLY MOVING LIMIT NUTS.

If other problems persist, call our toll-free number for
assistance - 1-800-528-2806.

Sensor for Auxiliary Reversing System

OPEN Limit Switch

Retaining Plate

WARNING

CLOSE Limit Switch

Aux. OPEN

Limit Switch

SAFETY

(Aux. Close) Limit Switch

6