45
• Control Keypad
4.8
Non Adjustable Protection and Fault Reset
4.8.1
Under/Over Frequency
Operational when the ASTAT-XT is energized and protects the motor when the frequency is less than 45 or greater
than 65Hz.
4.8.2
Phase Loss
Operational when the ASTAT-XT is energized, provided this protection has not been de-activated. Phase loss
protection trips the ASTAT-XT when 1 or 2 phases are missing.
Phase Loss
.
4.8.3
Phase Sequence
Operational when the ASTAT-XT is energized, provided this protection has not been de-activated. Phase sequence
protection trips the ASTAT-XT when phase sequence is wrong.
Refer to section
Phase Sequence
.
4.8.4
Wrong Connection
Operational after start signal. Trips if motor is not properly connected to the ASTAT-XT’s load terminals, when
internal disconnection is detected in the motor winding.
This protection is not active when
D. Set.:Generator Parameters
is selected.
4.8.5
Shorted SCR
Trips the ASTAT-XT if one or more of the SCRs have been shorted.
This protection is not active when
D. Set.:Generator Parameters
is selected.
4.8.6
Heat-Sink Over Temperature
Thermal sensors are mounted on the heat-sink and trip the ASTAT-XT when the temperature rises above 85ºC.
CAUTION
The over temperature protection is designed to operate under normal conditions,
i.e., in the event of extended low overload, insufficient ventilation due to fan
stoppage or air flow blockage.
Incorrect ASTAT-XT selection, frequent starting at max. conditions, or repeated
starting under fault conditions can cause the SCR to overheat and fail before the
heat-sink reaches 85°C, thereby causing the thermal sensors to trip the ASTAT-XT.
4.8.7
External Fault
External Fault becomes operational when ASTAT-XT is energized.
The ASTAT-XT will trip if contact closes for more than 2 sec.
CAUTION
Do not use External Fault when terminal 21 is not connected to ground.
4.8.8
Fault and Reset
When any of the above protection trips, the ASTAT-XT locks in a fault condition, disabling firing of the thyristors. The
Fault
LED lights, the fault description is displayed on the LCD and the fault relay operates.
•
For local reset after fault has been removed, press the
Reset
key.
•
Remote reset can be performed through terminals 7 or 8 (see
I/O Settings Parameters
section
When a fault occurs followed by a voltage outage, the fault condition is latched and reappears upon voltage
restoration.
Note:
Resetting of all faults, except for
Undercurrent
protection, (Local, Remote, Serial Link or Auto Reset) is not
possible as long as the START signal exists.
