Operation
41
Auto Reset Timing Diagrams (continued)
Fig 5.6.5 Auto Reset - Two Wire – Overload
The timing diagrams show the auto reset with a maintained two wire control system
The fault shown is an overload trip, the Control Supply maintained
In this instance the Auto Reset clears the trip but the overload (%) will take a certain amount of time to decay
If insufficient time is left before re-starts the overload will trip again repeatably until the Reset Attempts count exceeds it set value.
This must be considered and enough time left to allow the overload to decay to a low level
3-Phase Supply voltage
Control Supply
Start / Stop Input
Reset Input
(1)
Fault Relay
Restart Pending Relay
Imotor
Internal Reset
Reset Attempts PNU = 4
t0
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
Sequence of events
User Parameters (R/W)
Monitor Parameters (R/O)
t0 3 phase supply applied
PNU
Range
Default
PNU
Range
t1 Start signal applied, motor starts
t2 Motor reaches full voltage
Auto Reset
Off / On
Off
A
uto
R
eset Pending
0-1
t3 3 phase supply removed
Reset Delay
0-7200s
0s
A
uto
R
eset Exceeded
0-1
t4 Start signal must still be applied
Reset Attempts
0-10
0
A
uto
R
eset Delay Remaining
0-7200s
If it has been removed Auto Reset feature re-initialises
Reset Trips
All resettable trips
-
A
uto
R
eset Attempts Remaining
0-10
t5 Reset delay = 0 Restart Attempts =3
Trip Free Time
0-7200s
600s
A
uto
R
eset Trip Free Time Remaining 0-7200s
t6 Rest Signal must be low
If the trip is reset the Auto Reset feature re-initialises
Notes
t7 Reset delay = 0 Restart Attempts = 2
In this instance the starter has failed to Auto Restart in the set number of attempts
t8 3-Phase re-established
The starter will remain in the tripped state until reset
t9 Reset delay = 0 Restart Attempts = 1
To overcome this the Reset Delay time should be extended to allow the overload to cool
t10 Trip Free Delay = 0 Restart Attempts = 0
For Two Wire control reset occurs automatically when the start signal changes state from low to high, reset shown is programmable reset input
(1)
Reset Attempts = 0
Reset Attempts = 2
Overload (%)
Reset Attempts = 4
Reset Attempts = 3
Reset Delay
Reset Delay
Reset Delay
Reset Delay
Reset Attempts = 1
