Rockwell Automation 825 Smart Motor Manager User Manual - Manual (Page 70)

3-37 Functions
Publication 825-UM001B-EN-P January 2001
Applications
• The Warm Start function can be used in any installation that may have to be re-started
immediately after a voltage interruption.
• Chemical process and production plants (e.g., mixers, centrifuges, pumps, conveyor
systems)
• Mines and tunnels (fresh air fans, water pumps)
Figure 3.24 Example for t6x ,
e
= 10 s and Warm Trip Time = 70%
Load Current as Multiple of Full Load Current
T
rip Time
[s]
0.1
1.0
10.0
1.0
nx I
1.6
a
b
c
7.3
d
10 4
10 3
10 2
e
5 10.0 9 8 7 6 4 3.0 2.0 1.1
a) Time/current characteristic from cold when setting the trip time t6x ,
e
= 10 s.
b) Time/current characteristic after preloading with 1x ,
e
when the trip time from cold t6x ,
e
= 10 s and WARM START function is
disabled.
c) Time/current characteristic after preloading with 1x ,
e
(thermal utilization or winding temperature = 82%) when the trip time
from cold t6x ,
e = 10 s and WARM START function is enabled, setting: WARM TRIP TIME = 70% of the trip time from cold.
(The WARM TRIP TIME 7.3 s for 6x ,
e
is higher than (70% x 10) = 7 s because it depends on the winding and iron temperature
which are not at their highest value.)
d) If the thermal utilization (winding temperature) is higher than 82%, the WARM START function is automatically disabled. If
lower than 82% the WARM TRIP TIME depends on the winding and iron temperature and its range is 7.3…10 s.