MIL-P-80068 Positioners, Welding, Table Type, Gear Driven

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MIL-P-80068D

3.4.3.1 Table rotational system . Unless otherwise specified (see 6.2),

the speed of table rotation for class A or B shall conform to tables I or II,

be reversible, i n f i n i t e l y variable, and accurate within plus or minus 1

percent of the set speed adjustment. When specified (see 6.2), the rotational

system shall be provided with a high speed device separate from the standard

speed control, that will provide rapid rotation to maximum speed rate, without

affecting the set rotational speed adjustment.

3.4.3.2 Power table tilting system. C l a s s A positioners shall be pro-

P o w e r e d table tilting shall be

v i d e d with a power table til t i n g system.

accomplished either by an SCR (DC) motor drive or a (AC) brake motor drive

through a self-locking wormgear or gear reducer drive system. The system shall

be provided with limit switches or s e n s o r s to prevent over-tilting at either

extreme. The positioner shall be provided with a tilt protractor for accurate

i n d e x i n g of the tilt settings in increments of not greater than 5 degrees.

Positioners, sizes 7 and larger, shall have dual gear segments with dual drive

pinions. A braking system adjustment shall be provided with the system.

3.4.3.3 Manual table tilting system. Class B positioners shall be pro-

v i d e d with a self -locking wormgear d r i v e manual table tilting system. A

handcrank shall be provided to facilitate infinitely variable, full range

t i l t operations. A protractor shall be provided to accurately indicate tilt

s e t t i n g s in increments of 15 degrees or less. T h e tilt system shall be

p r o v i d e d with positive tilt stops t o prevent over-tilting in either extreme.

The table for sizes la, lb and 3 positioners shall be capable of tilting from

O to 90 degrees. Sizes 2 and 4 positioners shall be capable of tilting from O

to 135 degrees.

3.4.4 Electrical requirements. The positioner shall be wired to conform

to NFPA 79. Each machine shall b e wired to draw all of its electrical power

from a single circuit. Unless otherwise specified (see 6.2), each positioner

shall be designed to operate on 3-phase, 60-Hertz (Hz), 230/460 dual voltage.

Conversion from one voltage t o the other shall be accomplished by the

reconnection of existing components. The positioner

s h a l l be initially wired

as specified (see 6.2).

3 . 4 . 4 . 1 Motors. Motors shall meet the requirements of 3.4.4. The posi-

t i o n e r motor shall be rated for continuous

d u t y and shall have ball or

roller bearings of the sealed and permanently lubricated type. Unless other-

wise specified (see 6.2), alternating current (AC) motors shall be designed to

operate on 60-Hz. The motor enclosure shall meet the requirements for a drip-

proof enclosure. All motors shall conform to the requirements of NEMA MG-1.

Unless otherwise

3.4.4.2 Magnetic reversing starter and safety switch.

specified (see 6 . 2 ) , t h e p o s i t i o n e r s s h a l l be f u r n i s h e d w i t h a s a f e t y

d i s c o n n e c t i n g switch and reversing magnetic s t a r t e r , b o t h with overload

protection. E l e c t r o n i c type speed-drive c o n t r o l s shall be mounted in an

enclosure conforming to NEMA ICS 1.

3 . 4 . 4 . 3 Controls. Unless otherwise specified (see 6.2), the class A and

c l a s s B positioners shall be equipped with a pendant type control. When

specified (see 6.2), a foot-operated control shall be furnished. The pendant

control cable for class A positioners shall not be less than 15 feet long for