chain to within 1200 mm 4 feet of the floor and mount on inside of
building. Obtain reduction by use of roller chain and sprocket drive or
gearing. Provide chain cleat and pin for securing operator chain. Hoist
shall allow for future installation of power operators. The force required
to operate the door shall not exceed 15.75 kilograms 35 pounds.
2.6
ELECTRIC OPERATORS
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NOTE: Indicate location of motors and control
switches when electric operators are required.
Specify three-phase motors whenever three-phase
electric service is specified. Locate control
stations at least 1500 mm 5 feet above floor line,
so operator will have complete visibility of door at
all times. Place one control station about 600 mm 2
feet from door jamb, guide, or track.
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2.6.1
Operator Features
Provide operators of the drawbar type or side mount (jack shaft) type as
recommended by the manufacturer. Operators shall include electric motor,
machine-cut reduction gears, steel chain and sprockets, magnetic brake,
brackets, pushbutton controls, limit switches, magnetic reversing
contactor, a manual chain hoist operator as specified above for emergency
use, and other accessories necessary for operation. Design electric
operator so motor may be removed without disturbing the limit switch timing
and without affecting the manual operator. Provide the operator with
slipping clutch coupling to prevent stalling the motor. The emergency
manual operator shall be clutch controlled so that it may be engaged and
disengaged from the floor; operation shall not affect limit switch timing.
The manual operator is not required if door can be manual-pushup operated
with a force not to exceed 11.25 kilograms 25 pounds. Provide an
electrical or mechanical device that disconnects the motor from the
operating mechanism when the manual operator is engaged.
2.6.2
Motors
NEMA MG 1, high-starting torque, reversible type with sufficient horsepower
and torque output to move the door in either direction from any position.
Motor shall produce a door travel speed of not less than 200 mm two-thirds
foot or more than 300 mm one foot per second without exceeding the rated
capacity. Motors shall be operate on current of the characteristics
indicated at not more than 377 rad/s 3600 rpm. [Single-phase motors shall
not have commutation or more than one starting contact.] [Motor enclosures
shall be drip-proof type or NEMA TENV type.]
2.6.3
Controls
Each door motor shall have an enclosed, across-the-line type, magnetic
reversing contactor, thermal overload and undervoltage protection,
solenoid-operated brake, limit switches, and control switches. Locate
control switches at least 1500 mm 5 feet above the floor so the operator
will have complete visibility of the door at all times. Control equipment
shall conform to NEMA ICS 1 and NEMA ICS 2. Control enclosures shall be
NEMA ICS 6, Type 12 or Type 4, except that contactor enclosures may be Type
1. Each control switch station shall be of the three-button type with
buttons marked "OPEN," "CLOSE," and "STOP." The "OPEN" and "STOP" buttons
SECTION 08361
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