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SECTION IV - OPERATIONS
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INPUT CONNECTIONS - Connection to the input is made by means
of s. two pin connector.
With the FLOATING - GROUNDED slide
switch at the rear top of the chassis in the GROUNDED position,
pin 2 is grounded to the chassis and pin 1 is the positive
terminal.
The input wires should be surrounded by a shield
which is grounded to input connector shell.
If it is desired
to operate the input above ground, the slide switch should be
placed in the floating
position
and connection made. The shield
braid on the lead wires should be connected to the chassis, as
before.
For reliable
operation,
it may be necessary to shield
the input circuitry.
OPERATING CONTROLS -
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The power is turned on at the front panel.
Be sure that the instrument
is wired for the proper line volt-
age.
The 701 will
operate satisfactorily
on 50 or 60 cps.
For
method of changing line voltage consult schematic.
The trip
point is set by means of the large dial on the front
panel.
The RELAY OPEN light
will
go on when the limit
is exceed-
ed.
No other operating adjustments are necessary.
NON-LOCKING OPERATION - The instrument
is normally supplied for
non-locking
operation and the relay will
re-close
when the signal
drops more than 1% below the set point.
LOCKING OPERATION AND CONVERSION TO LOCKING OPERATION - On the
output plug at the rear of the instrument,
uins 1 and 8 are
jumpered.
If this jumper is removed, the-&it
will
perform as
a locking relay.
To reset,
pins 1 and 8 must be momentarily
shorted after
the signal has fallen
below the set limit,
When
units are supplied as locking relays,
a reset button,
connected
across pins 1 and 8, is mounted on the front
panel.
In such
units remote reset may be obtained by running wires from these
pins.~ If a non-locking
unit is converted to a locking type,
reset may be provided by an external
control
across the reset
pins or by installing
a pushbutton in the hole provided on the
panel.
REVERSE POLARITY AND LOW LIMIT OPERATION - If it is desired to
have the unit actuate an alarm when the input voltage falls
be-
low the set point it is advisable to reverse the polarity
of the
leads to the chopper so that the relay will
open when the signal
falls
below the set point.
In this way the system is fail-safe
for low limit
rather than high limit
operation.
IV - 1
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