GE MM3, Instruction Manual, Page: 128 / 230

6–4 MM3 MOTOR MANAGER 3 – INSTRUCTION MANUAL
A1 DATA CHAPTER 6: ACTUAL VALUES
– “RUNNING”: At least one contactor output relay is closed.
• A, B, C : This message displays the actual RMS current in each phase in amps. The
format is: “nn.n” at CT primary
≤
50 A and FLC
≤
50 A; or “nnn” at CT primary > 50 A or
FLC > 50 A.
• GROUND CURRENT : This message displays the ground fault leakage current flowing
from any phase to ground in amps.
• MOTOR LOAD : This message displays the motor load as a percentage of full load
current (FLC). The motor load is calculated as the average of the three motor phase
currents. When the value exceeds 100%, an overload condition exists. The MM3 Motor
Manager 3 eventually trips if the current is not reduced below 100% of FLC
× service
factor.
• THERMAL CAPACITY USED : This message displays the thermal memory accumulated
according to motor I
2
t history and chosen overload curve. A thermal capacity value
equal to 100% causes an overload trip.
• PHASE CURRENT UNBALANCE : Displays the percentage unbalance in the motor
phase currents. The unbalance is calculated as shown below.
(EQ 6.1)
(EQ 6.2)
In the above equations, I
AV
= average phase current, I
M
= current in a phase with maximum
deviation from I
AV
, and I
FLC
= motor full load current setting
• ACCELERATION TIME : This message displays the motor acceleration time from the
last motor start. This value is determined by the amount of time required for the
average phase current to go below 1.0
× full load current after a motor start.
• LAST STARTING CURRENT : This message displays the maximum current measured
during the last motor start. This value is saved until the next start or until power is
cycled on the MM3 Motor Manager 3.
• O/L TIME TO TRIP : This message displays the estimated time to trip based on the
present overload level and thermal capacity used. This message is only used in
conjunction with overload trips.
• POWER : This message displays the three phase power, calculated using phase A
current and voltage V
an
or V
ab
. This message will appear only if the VT PRIMARY
VOLTAGE
setpoint is programmed.
• ENERGY USED : This message displays the total accumulated energy used since last
cleared. This value is updated once every minute. This message will appear only if the
VT PRIMARY VOLTAGE
setpoint is programmed.
• VT VOLTAGE : This message displays the voltage present at the primary of the VT. This
message will appear only if the VT PRIMARY VOLTAGE setpoint is programmed.
6.2.2 Process Data
PATH: A1 DATA ÖØ PROCESS DATA
if I
AV
I
FLC
≥
: UB%
I
M
I
AV
–
I
AV
---------------------
100
×
=
if I
AV
I
FLC
<
: UB%
I
M
I
AV
–
I
FLC
---------------------
100
×
=
] PROCESS DATA
] ANALOG INPUT
= 142 UNITS