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C A U T I 0 N
Before putting relays into servic e , remove
all blocking which may have been ins ert�d for the
purpose of securing the parts during shipment, make
sure that all moving parts operate freely, inspect the
contacts to see that they are clean and @lose proper
ly , and operate the relay to check the settings and
el ectrical connections.
A P P L I C A T I O N
The
type CP relay is a three phase induction
disc type relay that operates upon phase reversal to
disconnect a motor from a c ircuit.
operate for an open phase on the motor unless the
motor is so heavily loaded that normal voltage cannot
be
maintained on al l phases.
will operate as soon as the machine is stopped and
prevent
it fro m being
wire is open.
This relay may also be app lied to c los e its con
tacts
on
either three
phase
undervoltage conditions on a system .
example, one relay is used to initiate source breaker
trip and another relay is used to supervise alternate
source
breaker
closing
scheme s.
C O N S T R U C T I O N
The type CP relay consists of a t hree phase volt
age
unit and an indic ating contactor switch when
supplied.
The principal component parts of the re
lay and their loc ation are shown in figures 1 and 2 .
A .
The
electromagnet
struc ture with a coil mounted on each leg.
connection
is
forme d
by
each coil together.
The other lead of the coils are
connected
to
separate
system .
When the coils are energized with a three phase
voltage,
a flux
is
induced
electromagnet.
The se
SUPERSEDES I . L. 41 -222. 2
*Denotes change from superseded i s s u e .
INSTALLATION
I N S T R U C T I O N S
TYPE CP REVERSE PHASE RELAY
The relay may not
Normal ly , the relay
started again if one phase
phase
overvoltage or three
For
on automatic
bus transfer
A N D
O P E R A T I O N
i s
an
"E"
type laminated
A wye
connecting one
lead of
pha ses
of
a three phase
in
each
leg
of the
fluxes
are
out-of-phase
•
OPERATION
with respect to each other since they are induc ed
by
out-of-pha se voltag es.
flux es is across an air gap in which a disc is lo
cated.
The out-of-phase flux es cause a torque to be
produc ed on the disc which moves to a position in
its travel that corresp onds to the three phase voltage
applied to the electromagnet.
in this position until the applied three phase voltage
i s changed, at which time, the disc will move to a
new
position that corresponds to the new voltage.
The out-of-phase fluxes are such that a positive
sequence
voltage tends to close the high voltage
contact while a negative s e quence voltage tends to
close the low voltage co ntact.
( which means negative s e quence phase rotation) will
cause the relay ' s low voltage contact to close.
contact will also close on unbal ance voltages that
c ontain
a ne gative sequence c omponent sufficient
to red uc e the relay torque to its low voltage trip
point .
B.
l n di e at i ng Co n t a c tor Swi t c h ( I C S )
The indicating contactor switch i s a small d-e
operated cl app er· type device.
to which leaf-spring mounted contacts are attached,
is attracted to the magnetic core upon energization
of the switch.
When the switch closes, the moving
con tacts bridge two stationary contacts, c ompleting
the
trip circuit.
Also , during this operation two
fingers on the arm ature deflect a spring located on
the front of the switch, which allows the operation
indicator target to drop.
outside of the case by a push rod located at the bot
tom of the c ase.
The front spring , in addition to holding the target,
provides restraint for the armature and thus controls
the pickup value of the switch.
C H A R A C T E R I S T I C S
The type CP really has adj ustable high and low
voltage contacts which can b e set around the peri-
E F F ECTIVE M ARCH 1 959
I . L. 41 -222.2A
•
MAINTEN A N CE
The path of the three
The disc will remain
A reversed phase
This
A magnetic armature,
The target is reset from the
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