Purpose Of Relays And Contacts - IBM 80 Customer Engineering Manual

CIRCUIT DESCRIPTION
37
Fi~ure 28. Type 80 Relay Cabinet
Runout Capacitor
Upon starting of the machine and the subsequent
closing of card lever contact 2, the runout capacitor is
charged to the
DC
circuit potential by means of a cir-
cuit through contact roll cover switch 1, card lever con-
tact 2, the 1,000 ohm resistor and capacitor in series,
and the CCR-B point.
Once charged, the capacitor retains its charge until
card lever contact 2 opens. Opening of card lever con-
tact 2 removes the potential impressed on the runout
capacitor, allowing it to discharge through the CCR-A
point, . the card control relay, the motor relay, contact
roll cover switch 2, and the CCR-B point. This dis-
charge current keeps the card control relay and the
motor relay picked until the current flow from the
capacitor falls below the value required to hold the
relay energized. As long as the motor relay remains
picked, the motor relay points maintain a circuit to the
drive motor. This allows the last card jn the machine to
be fed to its proper pocket before the machine stops.
The runout circuit is rendered inoperative when the
machine is stopped by opening of the pocket stop con-
tact, raising the contact roll cover, or depressing the
stop key.
The 47,000 ohm resistor which shunts the terminals
of the runout capacitor serves to bleed off the charge
after the machine has been stopped by operation of the
pocket stop device, raising the contact roll cover, or
depression of the stop key.
SORTING CIRCUITS
As
SOON
as the card brush makes contact with the con-
tact roll through a hole in the card, a circuit is com-
pleted to energize the sort magnet and the brush relay
as follows: from the plus
DC
circuit terminal, through
contact roll cover switch 1, card lever contacts 1 and
2 in parallel, outer to inner commutator brushes, com-
mon brush, contact roll, card brush, brush rel.ay, R-l,
sort magnet, F7, contact roll cover switch 2, to the
minus
DC
circuit terminal. Energizing the sort magnet
causes the attraction of its armature and the setup of
the proper combination of raised and lowered chute
blades to direct the card to the desired pocket.
Once it is energized, the sort magnet is held energized
through the outer and center commutator brushes and
the brush relay contact point. This circuit holds the sort
magnet energized until the center brush breaks con-
tact on the commutator common shortly after the 12
position on the card passes the card brush. Between the
12 position ot the leading card and the 9 position of
the following card, the armature return spring and the
armature knockoff come into play to restore the arma-
ture to its normal raised position in preparation for
sorting the following card.
PURPOSE OF RELAYS AND CONTACTS
Motor Relay
The motor relay is a heavy duty relay. Its purpose is
to complete a circuit to the drive motor. It is picked
when the start key is depressed and is held energized
primarily under control of the card lever contacts. When
the machine runs out of cards, the runout capacitor
discharges through this relay, holding it energized while
the last card is fed to its proper pocket. As long as the
motor relay is energized, its points complete a circuit to
the drive motor.
Card Control Relay
On machines built since February, 1951, this relay is
a duo relay. On machines built prior to the above date,