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SPECIAL

DEVICES

Sort

Suppression

Commutator

addition to the sort suppression switch, there

a sort suppression commutator which

mounted on

the card

feed

crankshaft (Figure

36).

This

a split

commutator which can

fastened

the shaft with-

out having to remove

any

basic

parts. Two brushes,

mounted in a holder fastened to the right end frame

assembly, ride the surface of the commutator and are

electrically connected each

time

the metal segment on

the

c-am

passes

under the brushes. This commutator

completes one revolution per card

cycle.

timed

to make contact when the card

nil

aV'

under

the

chute blade (12 time).

Energizing the Sort Magnet

During sort suppression, sensing of

any

value of

punching in the card

fires

the OA4G trigger tube in

the normal manner. Once

fired,

the OA4G remains

ignited until the center brush on the selector

commuta-

tor breaks near the end of the card

cycle.

Although

firing of the OA4G immediately removes the normal

negative grid

bias

from the 25L6 power tubes, the

sort magnet

not energized until 12 timfi when the

sort suppression commutator makes. When the

com-

mutator makes, it shunts around the

megohm

re-

sistor connected between the cathodes of the 25L6

tubes and the negative

side

of the line. This

megohm

resistor

connected

across

the DC circuit in series with

a 1 megohm resistor to form a voltage divider and

provide additional

bias

for

delaying the firing of the

25L6 tubes.

The voltage drop

across

the

megohm resistor

applied

the cathodes of the 25L6 power tubes

through octal pin

This voltage

of a positive value

in respect

the zero or negative

side

of the

circuit

and,

such, drives the cathodes of the 25L6 power

tubes positive in respect

the negative

side

of the

DC circuit. When the cathodes are driven positive

this manner, they

become

more positive than their

con-

trol grids. This, in effect, means that the control grids

are then negative with respect to their cathodes;

there-

fore, the 25L6 tubes fail to go into conduction even

though the normal negative grid

bias

removed when

the OA4G

fires.

When the sort suppression commuta-

tor makes

shunt around the

megohm resistor, the

additional

bias

removed, thus allowing the 25L6

tubes to energize the sort magnet for sorting the card

into the 12 pocket.

If the card brush

does

not

sense

a value in the card

because that column

blank or because the selecting

commutator contact bar for that value

retracted, the

OA4G will not

fire

and the card will pass to the reject

pocket.

Brand	IBM
Model	80
Category	Office Equipment
Language	English

IBM 80 User Manual

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IBM 80 Specifications