13
Instruction Leaflet
I. L. 29-889B
Effective June 2011
Instructions for Digitrip RMS 910 Trip Unit
eaton corporation
www.eaton.com
CAUTION
WHEN THE CIRCUIT BREAKER'S CONTACTS ARE OPEN IT MAY OR MAY NOT DISPLAY
THE BREAKER'S PHASE TO PHASE VOLTAGES. THIS DEPENDS ON THE BREAKER
TYPE. THE TYPE DS BREAKERS PICK UP THE PT MODULE’S CONNECTIONS ON THE
TOP SIDE WHILE THE TYPES SPB AND RD BREAKERS PT MODULE IS CONNECTED TO
THE BOTTOM SIDE (SEE FIGURE 2). A SECOND FACTOR TO CONSIDER IS WHETHER
THE BREAKER IS REVERSE FED IN APPLICATION. THEREFORE DO NOT RELY UPON
THE VOLTAGE READOUT AS A SOLE INDICATOR OF THE BREAKER'S ON/OFF STATUS
OR BREAKER'S VOLTAGE STATUS.
1.2.1.3 Instrumentation - Power, Power Factor and Energy
Values
The Digitrip RMS 910 Trip Unit displays power and energy values . By
using the circuit breaker current sensors and an integrally mounted
Potential Transformer Module shown in Figure 11, power and energy
values are computed and displayed in the four-digit display window
on the face of the Trip Unit .
The power, power factor and energy parameter values displayed in
the window on the face of the Trip Unit include:
•
Peak Demand in MW (Megawatts),
•
Present Demand in MW (Megawatts),
•
Energy (Consumed) in MWh (Megawatt-hours), and
•
Power Factor .
Four "Green" LEDs, as shown in Figure 1, are provided to indicate
which value is displayed . The same "STEP" push-button pressed and
released to view the different values of current and voltage is also
pressed and released to view the power, power factor and energy
values .
The
Peak Demand
parameter is based on a sampling window of
fifteen (15) minutes . Power is repeatedly averaged over this inter-
val and the maximum average is displayed as Peak Demand . The
demand window is not a "sliding window" . It is more like a 'jumping
window" . When the Trip Unit is first energized, there is a delay of
15 minutes before the first non-zero value is displayed . To reset the
peak demand value shown in the display window back to zero, press
and release the (Black) "Demand Reset" push-button, shown adjacent
to the "Peak Demand" label in Figure 1 .
otee:
N
The peak demand function requires that 120 VAC control power be sup-
plied to the Power 1 Relay Module .
The
Present Demand
is a power value averaged over approximately
one second . To view the "Present Demand" value in the display win-
dow, press and release the "STEP" push-button several times until
the LED next to "Present MW” is lighted .
The range, assumptions and accuracy parameters for peak and pres-
ent power demand values displayed are:
Range-
0 to 9 .999 MW
Assumes -
5% < Current < 175% of the Plug Rating I
n
Sampling Window-
15 min.
for
Peak Demand, ~1 sec.
for
Present Demand
Accuracy-
± 4%
of (Frame Rating x 600 V) for Series C
®
R-Frame or Type SPB circuit breakers,
or
± 4%
of (Current Sensor Rating x 600 V) for Type
DS circuit breakers .
The System Power Factor
(PF)
is a unitless parameter that is dis-
played locally on the Digitrip RMS 910 . The range assumptions and
accuracy for the system power factor function values are:
Range- From 0 .5 (lagging) to 0 .5 (leading)
Assumes-
Balanced three-phase load, per ANSI Std . C 12 .1-
1988
Current-
> 20% of Frame Rating for Series C
®
R-Frame or Type
SPB circuit breakers .
Current-
20% of [Current] Sensor Rating for Type DS circuit
breakers .
Accuracy-
± 0.02
The
Energy
parameter is the summation of the average power over
time and it is expressed in megawatt-hours (MWh) . The value is
updated approximately once a second . The value cannot be reset
locally . After the maximum value is reached, the display automati-
cally rolls over to zero .
The range and accuracy parameters for energy demand values dis-
played are:
Range-
0 to 999 .9 MWh if I
n
< 1000 A
0 to 9999 MWh if I
n
> 1000 A
Assumes-
5% < Current < 175% of the Plug Rating I
n
Accuracy-
± 5% of (Frame Rating x 600 V x time) for Series
C
®
R-Frame or Type SPB circuit breakers .
or
± 5% of (Current Sensor Rating x 600 V x time)
for Type DS circuit breakers .
Polarity
Figure 9. Rating Plug.
Polarity
Marks
Hinged
Cover
Battery
Rating Plug
is for Type
SPB Circuit
Breakers Only
Rating Plug
for R-Frame
and DS
Breakers
are Similar
Values for Short
Delay S1 and S2
Instantaneous
M1 and M2
Settings
Pull Tab to
Remove
Battery
Rating Plug
Identification
"Battery
Check"
Push
button
Battery "OK"
if LED Lights
"GREEN" when
"Battery Check"
Button is
Pushed
Rating Plug
Retention
Screw
Battery
Removal Tab
Polarity
-
+
