Multilin PROTECT 4A-120, Instruction Manual

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1.2 PROTECT 4A FEATURES
A microcomputer housed in a rugged, industrial package al-
lows the Protect 4A to provide accurate, economical protection
in a unit that will outlast the life of the motor. Since many new
factories are using programmable controllers as automation in-
creases, a 4-20mA output of motor current is also provided elimi-
nating the need for an additional transducer. This output gives
a direct reading of motor current.
Fault diagnosis after a trip is displayed on front panel indica-
tors. This will allow operators and electricians to rapidly isolate
and correct problems. It is possible to verify correct operation
of an installed Protect 4A relay to ensure that the motor protec-
tion is functioning properly.
One Protect 4A relay is required per motor. Phase and ground
fault currents are monitored through current transformers so that
motors of any line voltage can be protected. The relay is used
as a pilot device to cause a contactor or breaker to open under
fault conditions; that is, it does not carry the primary motor cur-
rent. Figure 1-1 shows how the Protect 4A is connected into a
system for complete motor protection.
TABLE 1-1 PROTECT 4A FEATURES
FEATURES
•
Fault Diagnosis
•
4–20mA Output of Motor
Current
•
Overload Status Indicator
•
Economical
•
Compact — Plug In
•
Universal Models
Simplify Spares
PROTECTION
•
Overloads
(8 Time Cur ves)
•
Locked Rotor/Stall
•
Mechanical Jam
•
Multiple Starts
•
Single Phasing
•
Ground Fault/Earth
Leakage (Trip or indica-
tion only)
•
Overheating (Thermistor
Sensing)