Relay Rating
BF Timer Setting Capacitance
48 Vdc
1 8
ms
or higher
1 8 MFD
1 25 Vdc
1 8
ms
or higher
6 MFD
1 25 Vdc
35
ms
or higher
1 3 MFD
250 Vdc
1 8
ms
or higher
2.5 MFD
250 Vdc
35
ms
or higher
13 MFD
Any value of capacitance effectively in series
with the input greater than that shown above
might result in an undesired trip operation.
Ordinarily capacitance should not be con
nected from the lead connecting the 52a contact to
the relay and ground. A value of 0.5 M FD could
cause the 52a input to stay on for 1 . 5 ms (48V
relay), 4 . 5 ms ( 1 25V relay) and 20 ms (250V relay)
after the 52a contact opened .
X
RELAY
Coil resistance is 1 500 ohms ± 5% and rated
for 24Vdc operation . The seal-in contact will
pickup providing the B FI (62X , 62Y) initiate con
tacts are closed for a minimum of 8 ms. A second
contact is wired to the relay terminal to provide a
retrip feature.
AR RELAY
The coil resistance is 630 ohms ± 5 % and will
operate in series with the appropriate resistor
from 80% to
II
0% of rated voltage.
The operate speed is 3 to 5 ms at rated voltage.
The dropout time is 30 to 45 ms (diode around the
coil). There a re 4 normally o pen contacts
available.
I N DI CATING CONTACTOR SWITCH (I CS)
The coil resistance is approximately 6 . 5 ohms
on the 0.2 amp tap and 0 . 1 5 ohms on the 2.0 amp
tap.
TRIP C I RC U IT
The main contacts will safely close 30 amperes
at 250 Vdc and the seal-in contacts of the ICS will
4
safely carry this current long enough to trip a cir
cuit breaker.
SETT I N G S
OVE R C U R RENT D ETECTOR
The pickup of the overcurrent unit is obtained
by means of a tap screw and tap block in conjunc
tion with the tap multiplier knob setting located at
the front of the overcurrent unit module. This per
mits a continuous adj ustment over the range of 0.5
to 1 3 . 5 amperes. Each tap setting permits ad
justing the pickup over a 3 to
I
range.
There are 2 or 3 phase inputs depending on the
relay style. Each one has its own tap block . N or
mally all the phase settings should be in the same
tap. The operate point for each phase should be
within 5% of each other. There are trimpots for
each input located on the overcurrent module
which are factory adj usted but which may be read
justed if the 5% accuracy m ust be improved at any
one pickup point.
The ground unit pickup is obtained similar to
the phase above and is independent of the phase
pickup. This permits the ground setting to be lower
than the phase setting.
The ph ase units m ust be set below the
minimum expected fault current and the ground
unit set below the minimum expected residual
(310) current. Settings should be made to assure a
mu ltiple of pickup of at least 2 under minimum
fault conditions.
CONTROL TI M E R
The control timer can be set b y use of a screw
driver to adjust the trimpot which is accessible
through the hole in the front plate of the timer
module. Clockwise rotation will increase the on
time. An oscilloscope or electronic timing device
can be connected between the bottom red test j ack
on the timer module front plate and terminal 8 of
the relay (common negative).
The control timer should be set for at least 1 6
milliseconds longer than the B F timer. This allows
for pickup time of the reed relay ( l to 3 ms), AR
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