GE AKR-30S Manual page 13

The RMS-9 MicroVersaTrip
system for AKR low voltage
power circuit breakers ? On­
sists of four parts: plug-In
protection programmer, flux­
shift trip device, current sen­
sors and rating plugs.
The programmer contains
a current sensor-powered,
solid-state logic unit and in­
corporates rotary adjus
ment switches for up to nme
functions, as well as targets
for mechanical fault trip indi­
cation.
MicroVersaTrip RMS-9
represents the latest tech­
nology in digital solid-state
programmers.
Sensing of
RMS Digital
Sinusoidal and Non­
sinusoidal
The RMS-9 provides accu­
rate overload protection for
both sinusoidal and non­
sinusoidal currents by direct
measurement of the true
rms content of the curr.ent
wave. This is accomplished
by microprocessor digital
sampling techniques.
F IXOd <:: u rrL'rl\
Sensor
12
Therefore, the solid state
microprocessor is not af­
fected by component toler­
ance and does not require
compensation for signal dis­
tortion. Since the design is
based on complimentary
metal oxide (CMOS) tech­
nology, it is less sensitive to
extraneous noise produced
�
­
by lighting, instrumentation,
radio, etc.
The solid state microproces­
sor technology and fast ana­
log to digital converters
make it possible to measure
the magnitude of the phase
current over a number of
time periods within the cy­
cle. The RMS-9 sampling
rate of 27 per cycle for each
phase allows for errors of
less than 1 % on systems
with distortions through the
13th harmonic. This digital
sampling technique pro­
vides the most accurate
system protection fo � distri­
bution systems that mclude
ac and de variable speed
drives, rectifiers, induction
heating, and other loads
MicroVersaTrip
that cause non-sinusoidal
currents.
A FuH Function lnp Unit
Available with Vanous
Gombmat1ons of
Protection Features.
The RMS-9 trip line of pro­
grammers provides maxi­
mum breaker to breaker se­
lectivity and custom load
protection. Short-ti � e a � d
Ground Fault functions In­
clude the flexibility of coordi­
nation with and without an
12T ramp. Type AKR power
circuit breakers are avail­
able with H igh Range In­
stantaneous, No Instanta­
neous, or Switchable (OFF)
Instantaneous, and Ground
Fault. All programmers in­
clude a clear plastic cover
with provisions for sealing
for tamper-proof installation.
Flux-sh ift Trip Device
The flux-shifter is a low en­
ergy, positive action tr
device that is automatically
powered and controlled by
RMS-9 Sy
e m Components
· s t
the protection programmer.
The low energy signal from
the programmer counteracts
the strength of a permanent
magnet in the flux-shifter, al­
lowing a spring to unseal
the magnet·and trip the
breaker.
C urrent Sensors
Three toroidal current sen­
sors provide maximum flex­
ibility and reliability with
minimum signal error. Cur­
rent sensor ratios are shown
in Table 30. 1 , page
a i
R
t n�� Plugs Provide
Convenient Flexibility
Load
in Ma!tching
Req uirements
All RMS-9 programmers uti­
lize a broad range of field
installable rating plugs for
future uprating capability,
minimum size cable selec­
tion , and an extra degree of
�
coordination flexibility.
pping
30.