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CHAPTER 7: TESTING
7.2.1
Phase Current
Functions
MM3 MOTOR MANAGER 3 – INSTRUCTION MANUAL
7.2
Functional Tests
Any phase current protection is based on the ability of the MM3 Motor Manager 3 to read
phase input currents accurately. Make the following settings:
S2 PROTECTION
MOTOR PROTECTION THERMAL
S1 CONFIGURATION
To determine if the relay is reading the proper input current values, inject different phase
currents into the CT inputs and view the current readings in
displayed current should be equal to the actual injected current.
Phase current values will be displayed even if the motor status is stopped; that is,
contactor A has not been activated by a start command. Very low currents are displayed
as 0 A.
Once the accuracy of the phase CT inputs has been established, various phase alarm and
trip condition tests can be performed by altering setpoints and injected phase currents.
To simulate an overload condition, enter the
menu and set
THERMAL
OVERLOAD CURVE NUMBER
"50 A".
PHASE CT PRIMARY AMPS
that the Running LED goes on. Inject a current of 10 A into all three phases. The relay will
display a current value of:
displayed current = actual injected current × 100/5 = 10 × 100 / 5 = 200 A.
This represents 4 times the phase
400% overload and curve #4, contactor A will change state 23 seconds after the overload
is first applied. When this occurs, the Running LED turns off and the Tripped and Stopped
LEDs are lit. After the trip has occurred, use the
verify that the thermal capacity used is now 100%. Press the RESET key to reset the MM3
Motor Manager 3.
To prepare the MM3 Motor Manager 3 to simulate an unbalance alarm, make the following
settings. In the
S2 PROTECTION
PHASE UNBALANCE
ALARM: "ENABLE"
In the
S4 CONTROL
AUX RELAY 1 CONFIG
AUX RELAY 1
FUNCTION: "ALARMS"
In the
S4 CONTROL
AUX RELAY 2 CONFIG
AUX RELAY 2
FUNCTION: "TRIPS"
Inject 5.0 A into all three phase CTs. The MM3 Motor Manager 3 displays a balanced phase
current of 100 A for each phase. While still viewing actual values, slowly begin decreasing
phase 1 current until the
UNBALANCE ALARM
energize when the alarm is present. Unbalance is calculated as follows:
For average currents greater than motor full load:
I
n
----------------
STARTER
STARTER
TYPE: "FV NON REVERSING"
S2 PROTECTION
to "4" and
should be set to "100 A". Close the start A input and note
FULL LOAD CURRENT
A1 DATA
MOTOR PROTECTION OPTIONS
menu, set:
menu, set:
message comes on. Auxiliary relay 1 should
I
–
av
>
15% (alarm)
30% trip
I
av
FUNCTIONAL TESTS
FULL LOAD
CURRENT: "100 A"
A1 DATA
MOTOR
DATA. The
MOTOR PROTECTION
FULL LOAD CURRENT
setpoint. Therefore, based on a
MOTOR DATA
actual values to
menu, set:
to
(EQ 7.1)
7–3
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