Rockwell Automation 592- E300 Overload Relay User Manual - Manual (Page 135)

Rockwell Automation Publication 193-UM015B-EN-P - June 2014 135
Protective Trip and Warning Functions Chapter 5
Under Voltage Protection
Electric motors will consume more electric current when the voltage supplied to
the motor is lower than the motor name plate rating. This could cause damage to
an electric motor over an extended period of time. The E300 Electronic Overload
Relay can monitor for this condition with its Under Voltage Trip and Warning
function to detect for low voltage levels to minimize motor damage and loss of
production.
Under Voltage Inhibit Time
Under Voltage Inhibit Time (Parameter 355) allows the installer to inhibit an
under voltage trip and warning from occurring during the motor starting
sequence. It is adjustable from 0…250 seconds.
Table 122 - Under Voltage Inhibit Time (Parameter 355)
Under Voltage Trip
The E300 Electronic Overload Relay will trip with an Under Voltage indication
if:
• No trip currently exists
• Under Voltage Trip is enabled
• Voltage is present
• Under Voltage Inhibit Time has expired
• The minimum phase voltage is less than the Under Voltage Trip Level for a
time period greater than the Under Voltage Trip Delay.
If the E300 Electronic Overload Relay trips on an under voltage, the:
• TRIP/WARN LED status indicator will flash a red 1-long / 1-short blink
pattern
• Bit 0 in Voltage Trip Status (Parameter 5) will set to 1
• Bit 0 in Device Status 0 (Parameter 20) will set to 1
• Any relay outputs configured as a Trip Relay will open
• Any relay outputs configured as a Control Relay will open
• Any relay outputs configured as a Trip Alarm will close
• Any relay outputs configured as a Normal Relay will be placed in their
Protection Fault state (if so programmed)
Default Value 10
Minimum Value 0
Maximum Value 250
Parameter Type USINT
Size (Bytes) 1
Scaling Factor 1
Units Sec