Application; Ratings; 12Capi5A(-)A - GE CAP15A Instructions Manual

GEI-12083
The Type CAP15A and Type CAP15B relays consist of one three-phase unit, with one rotor mounted on a
shaft. The contact assembly consists of two electrically separate contacts, one normally-open and one
normally-closed. The normally closed contacts are held closed, when the relay is not energized, by means
of two spiral springs which also complete the control circuit to the moving contacts.
APPLICATION
The CAP15A relay is a three-phase induction-cylinder power directional relay. Its principal application
is to perform the directional duties in directional overcurrent scheme. The recommended A-C external wiring
connection for the Type CAP15A relay are shown in Figure 9, connection A. I~ith this connection the relay
has maximum torque on a balanced three-phase condition when the line current lags its unity power factor po-
sition by 40 degrees in the tripping direction. On a zero voltage phase-to-phase fault just beyond the
relay terminals, the relay has maximum torque when the current laqs its unity power factor position by 70
degrees in the tripping direction. Figure 2 demonstrates the directional characteristics of the preferred
connection (60 degree connection). The 30 degree and 90 degree connections are also shown in Figure 9,
with the corresponding angle of maximum torque for balanced conditions.
If the relay is used in an application where there is the possibility of a momentary reversal of power
immediately following the clearing of a fault, and if the overcurrent relay contacts have closed, it is
necessary to provide directional control to prevent false tripping. In the case of time-delay overcurrent
relays, this may be done by allowing the overcurrent relays to operate only if the fault is in the pro-
tected direction. If the overcurrent relay is instantaneous in operation, discriminating control may be
obtained by using the right-hand contact to contrr~ a Type HGA auxiliary relay as shown in Figure 3.
If both directional contacts are used and if a momentary reversal of power immediately following the
clearing of a fault is not possible, it is still advisable to use some method of directional control.
This is evident because when a fault is removed, sufficient energy will be stored in the deflected contact
to
caus~
rebound to the other contact. If only one contact is being used, the stored energy in the other
contact may be substantially eliminated by reversing the contact barrel and its sleeve in the contact hol-
der thereby using the back end 'as a solid stop. This is done by loosening the screw that locks the barrier
in place, remove the barrel and sleeve, unscrew toe sleeve from the Barrel, insert the sleeve into the con-
tact support from the inside and screw the barrel into it from the outside with the contact pointing cut.
When the stop is located where desired, lock in position by tightening the screw. It has been found ad-
visable to remove the corresponding moving contact finger as well.
The Ty~o CAP15B relay is a general purpose reverse power relay. This relay measures true watts and is
practically unaffected by the reactive component of power. Because this relay is a high speed relay, it
should always be used with a suitable timing relay in order to prevent undesired operations during system
disturbances which cause momentary power reversals. An application of the CAP15B is shown in Figure 13.
RATINGS
12CAP15A(-)A
The 12CAP15A(-)A relays are available at voltage ratings of 115, 130, 208 and 230 volts. The current
circ~its are continuously rated at five amperes with frequencies available at 25, 35, 50 and 60 hertz.
The targets and holding coils are available at 0.2 and 1.0 amperes d-c rating.
12CAP15B(-)A
The 12CAP15B(-)A relays are available at voltage ratings of 115, 208, and 230 volts. The current
circuits are continuously rated at five amperes with frequencies available at 25, 50 and 60 hertz. The
targets and holding coils are available at 0.2 and 1.0 ampere d-c rating.
These instructions
do
not purport
to
cover all details
or
variations in equipment nor
to
provide for
every possible contingency
to
be met'in connection with installation, operation
or
maintenance. Should
further information be desired
or
should particular problems arise which are not covered sufficiently for
the purchaser's purposes, the matter should be referred
to
the General Electric Company.
To the extent required the products described herein meet applicable ANSI, IEEE and NEMA standards;
but no such assurance is given with respect to local codes and ordinances because they vary greatly.
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