13
Instruction Leaflet
I. L. 29-888B
Effective July 2011
Instructions for Digitrip RMS 810 Trip Unit
eaton corporation
www.eaton.com
1.2.1.2 Instrumentation - Power and Energy Values
The Digitrip RMS 810 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 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), and
•
Energy (Consumed) in MWh (Megawatt-hours)
Three "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 and energy values .
The
Peak Demand
parameter is based on a sampling window of
fifteen (15) minutes . Power is repeatedly averaged over this interval
and the maximum average is displayed as Peak Demand . The dis-
played value is the highest or peak value since the (Black) “Demand
Reset”, push-button was last pressed and released . 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 min-
utes 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 / 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
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 .
The energy value is stored in the Trip Unit memory . As long as the
120 Vac control power is maintained to the Power / Relay Module,
it can be viewed . If the 120 Vac control power is lost and then is
restored, the Energy value is also restored .
The Digitrip RMS 810 Trip Unit presumes that power is flowing into
the "top" and out of the bottom of the circuit breaker (positive flow of
power) . If the power flows in the opposite direction, i .e ., bottom to
top, the value of power will not be displayed continuously . Instead,
the power value in the display window will alternate with the
coded message "NPOW" . This message, alternating with the value,
indicates power flowing out of the top of the circuit breaker . This
condition will occur when a Main circuit breaker is "reverse fed" and
can frequently occur for three breaker schemes that involve a “tie”
breaker . The "NPOW” message can be defeated on type
DS
and
type
SPB
breakers only by inserting an appropriate “jumper" (see
wiring diagram for your type of circuit breaker listed in Section 6) .
1.2.2 Messages Displayed After ALARM or TRIP
During an ALARM condition or after a circuit breaker TRIP opera-
tion, one of the coded messages listed in Table 3 will appear in
the display window, provided control power is still available for the
Power/Relay Module (see Section 1 .4) . If the "STEP" push-button is
pressed, the message will be deleted so that menu values of cur-
rents (kA) etc . can be viewed .
otee:
N
The user should view all of the currents . The first value you see may
not be the greatest .
Following a circuit breaker TRIP operation, the display window
indicates the reason for trip, using coded messages such as, INST
(Instantaneous Trip), LDT (Long Delay Trip) etc . As with the ALARM
function, press and release the "STEP" push-button to delete the
reason for trip message and the display window will then show the
values of current at the time of trip (see Notes (1), (2), and (3) under
Table 3) . The values remain in memory, and the "red" reason for Trip
LED (see Figures 1 and 3 through 8) remains lighted, until the Trip
Unit is reset by pressing and releasing the "TRIP RESET push-button
in the lower right corner of the Trip Unit (see Figure 1) .
otee:
N
After a trip condition, RECORD all Values of interest and note which
"RED" LEDs are lighted . Correct the cause of the overload or fault BEFORE
YOU RESET the Trip Unit to avoid repeated tripping .
The LOCKOUT after trip feature requires the Trip Unit to be reset
before the breaker can be closed again .
For examples of how to interpret the display after an overload and
after a short-circuit, see Appendix B .
1.2.1.1 ROM Error ... See I.L.
If the message, "ROM Error . . . See I .L .", scrolls across the display
window, it means that a non-fatal error has been detected some-
where in the Trip Unit's non-volatile memory . The Trip Unit will still
function to protect the circuit, but the calibration may be degraded
by a few percent . The Time-Current Curve tolerances may be exceed-
ed in some cases by as much as 12% .It is not necessary to trip and
lockout the breaker . There may also be errors in values of current,
energy, and power displayed and they could even be greater than
12% . The scrolling message will not remain in the window constant-
ly but is repeated periodically to remind you to replace the Trip Unit .
1.3 Frame Rating, Sensor Rating (Where Applicable) and
Rating Plugs
The
Frame Rating
of a circuit breaker is the maximum RMS cur-
rent it can carry continuously . The maximum Short-Circuit Current
Ratings of the circuit breaker are usually related to the Frame Rating
as well .
It is often times desirable to be able to choose a current value
(I
n
)
,
less than the full frame rating, to be the basis for the circuit break-
er's protection functions, without affecting its short-circuit current
capability . For the Digitrip RMS 810 Trip Unit the maximum continu-
ous current (I
n
) is set by the
Rating Plug
(and/or
Current Sensors
,
