TYPE 4208 “H”
AC SIGNAL PANEL
INTRODUCTION
The “H” panel provides AC power to control
the series connected alarm signaling devices. It can
operate one signal circuit (HI) or two signal cir-
cuits (H2). These circuits can be operated together
or separately.
The number of “‘H” panels used in a system is
determined by the system requirements.
CIRCUIT OPERATION (FIG. 12)
NORMAL OPERATION (H2 CIRCUIT)
Alarm Condition
During normal operation, 120VAC Operating
Power is applied to terminal 120V. Current to
supervise the signal circuits flows through fuse F 1,
terminal 3, resistor R2, contacts K3B (5&8), termi-
nal B, terminal G2, the signaling devices, terminal
G2, fuse F3, terminal C, contacts K3A (l&4), resis-
tor Rl, contacts K2B (5&8), terminal D, terminal
G 1, the signaling devices, terminal G 1, fuse F2, ter-
minal E, contacts K2A (l&4), diode Dl, relay Kl
(energizing K 1 ), terminal A to terminal NEUT.
When an alarm occurs, -24VDC is applied to ter-
minal AL2 in the “H” panel. At terminal AL2 the
current flow splits into two paths.
One path is through terminal 2, relay K2 (energi-
zing K2), terminal G., terminal F to +24VDC at ter-
minal AL1 .
The other path is from terminal AL2 through
terminals 2 and 1, relay K3 (energizing K3), termi-
nal F to +24VDC at terminal ALl.
Relay Kl energizes, but the signaling devices do
not sound because of the current limiting effects
of resistors Rl and R2.
TROUBLE CIRCUIT
An open in the alarm signaling devices or in the
signal circuit wiring will cause relay Kl to de-ener-
gize. When the Kl contacts transfer, -24VDC from
terminal TBl is applied to terminal 5 in the “AX”
or “A” panel which causes a trouble condition.
Current flows from TBl through terminal 7, con-
tacts KID (4&12), contacts KlB (2&10), terminal
H, terminal TB2 to terminal 5 in the “AX” or “A”
panel. (Refer to “AX” or “A” Panel - Trouble
Condition, paragraph three.)
When relay K2 energizes its contacts transfer and
current is supplied from Tl, through terminal 6,
contacts K2A (3&l), terminal E, fuse F2, terminal
Gl, the signaling devices (sounding the devices),
terminal Cl, terminal D, contacts K2B-(8&6), ter-
minal A to terminal NEUT.
When K3 energizes, current is supplied from T2
through terminal 5, contacts K3A (3&l), terminal
C, fuse F3, terminal G2, the signal devices (sound-
ing the devices), terminal G2, terminal B, contacts
K3B (8&6), terminal A to terminal NEUT.
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