2.3.2
Manual Hand-Chain Operation
Provide galvanized, endless chain operating over a sprocket and extending
to within 900 mm 3 feet of floor. Obtain reduction by use of roller chain
and sprocket drive or suitable gearing. Gears shall be high-grade gray
iron, cast from machine-cut patterns. The pull required to operate the
door shall not exceed 15 kgs 35 pounds.
2.3.3
Manual Crank Operation
Provide a fully enclosed, permanently lubricated, geared power unit mounted
860 mm 34 inches above the floor; a removable crank; and a vertical shaft
connecting the unit to the counterbalance drive system. The force required
to operate the door shall not exceed 9 kgs 20 pounds. Gears shall be of
high-grade gray iron, cast from machine-cut patterns.
2.4
ELECTRIC OPERATION
2.4.1
Operator Features
Provide operators complete with electric motor, machine-cut reduction
gears, steel chain and sprockets, magnetic brake, overload protection,
brackets, pushbutton controls, limit switches, magnetic reversing
contactor, and other accessories necessary for proper operation. The
operator shall be so designed that the motor may be removed without
disturbing the limit-switch timing and without affecting the emergency
auxiliary operators. Make provision for immediate emergency manual
operation of door by chain-gear mechanism in case of electrical failure.
The emergency manual operating mechanism shall be so arranged that it may
be put into and out of operation from the floor, and its use shall not
affect the timing of the limit switches. Provide an electrical or
mechanical device which will disconnect the motor from the operating
mechanism when the emergency manual operating mechanism is engaged.
2.4.2
Motors
Shall conform to NEMA MG 1, high-starting torque, reversible type of
sufficient horsepower and torque output to move the door in either
direction from any position, and produce a door travel speed of not less
than 0.2 two-thirds foot or more than 0.3 meters per second one foot per
second, without exceeding the rated capacity. Motors shall be suitable for
operation on current of the characteristics indicated and shall operate at
not more than 3600 rpm. [Single-phase motors shall not have commutation or
more than one starting contact.] [Motor enclosures shall be the drip-proof
type or NEMA TENV type.] Install motors in approved locations.
2.4.3
Controls
Each door motor shall have an enclosed, across-the-line type, magnetic
reversing contactor, thermal-overload protection, solenoid-operated brake,
limit switches, and remote control switches at locations indicated. Remote
control switches shall be at least 1500 mm 5 feet above the floor line, and
all switches shall be located so that the operator will have complete
visibility of the door at all times. The control equipment shall conform
to NEMA ICS 1 and NEMA ICS 2. Control enclosures shall be NEMA ICS 6, Type
12 or Type 4, for interior locations and Type 4 for exterior locations,
except that contactor enclosures may be Type 1. Locate control switches
inside the building unless otherwise indicated. Each switch control
station shall be of the three-button type, with the buttons marked "OPEN,"
SECTION 08331N
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