Rockwell Automation 193-EC1_2_3_5, 193-ECPM,592-EC1_2_3_5 E3 and E3 Plus Solid-State Overload Relay User Manual User Manual
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Rockwell Automation Publication 193-UM002I-EN-P - December 2011
Chapter 3 Protective Trip & Warning Functions
• minimum phase current is less than the UL Warn Level.
When the Underload Warning conditions are satisfied, the:
• TRIP/WARN LED will flash an amber 7-blink pattern,
• bit 6 in Parameter 15, Warning Status, will set to “1”, and
• bit 1 of Parameter 21, Device Status, will set to “1”.
UL Warn Level, Parameter 48, allows the installer to define the current at which
the E3 Overload Relay will indicate a warning. It is user-adjustable from
10…100%
➊
of the FLA Setting, Parameter 28.
➊
50…100% for devices with firmware revision (FRN) 1.003 and earlier.
Thermistor/PTC Protection
The E3 Plus Overload Relay models -EC2 and -EC3 provide terminals IT1 and
IT2 for the connection of positive temperature coefficient (PTC) thermistor
sensors. PTC sensors are commonly embedded in motor stator windings to
monitor the motor winding temperature. When the motor winding temperature
reaches the PTC sensor’s temperature rating, the PTC sensor’s resistance
transitions from a low to high value. Since PTC sensors react to actual
temperature, enhanced motor protection can be provided to address such
conditions as obstructed cooling and high ambient temperatures.
The following table defines the E3 Plus Overload Relay’s PTC thermistor input
and response ratings.
Table 21 - E3 Plus PTC Input Ratings
The following figure illustrates the required PTC sensor characteristics per IEC-
34-11-2.
IMPORTANT The Underload Warning function does not include a time delay feature.
Once the UL Inhibit Time has expired, the Underload Warning indication
is instantaneous.
Resistance:
Response
3400
Ω ± 150 Ω
Reset
1600
Ω ± 100 Ω
Short-Circuit Trip
25
Ω ± 10 Ω
Maximum Voltage at: PTC Terminals (R
PTC
= 4k
Ω
) < 7.5V
PTC Terminals (R
PTC
= open) 30V
Maximum Number of Sensors
6
Maximum Cold Resistance of PTC Sensor Chain
1500
Ω
Response Time
800 ms