Grundfos LC 231 Manual Del Usuario página 20

Note that the curves are examples and cannot be
used for readings.
IEC trip curves
Y
10000
5000
1000 1000
500
170
100 100
50
A
10 10
5
1
0.0 1.0 2.0 3.0 4.0 5.0
2.25
Pos. Description
Y Time [s]
x I
X
A Class "p"
1 Class 30
1 Class 20
3 Class 10
4 Class 5
Example:
1. Set the IEC trip class to class 20.
2. Set the overload limit to 10 A. The rated motor
current is stated on the nameplate.
At a motor current of 22.5 A (10 x 2.25), a pump is to
cut out after approx. 170 seconds. In addition to IEC
trip curves, a fixed 4 x I in 2 seconds is
rated
implemented to protect especially small motors from
overheating (see grey area on drawing).
Contactor Current Protection (CCP)
In addition to the IEC trip class, a Contactor Current
Protection (CCP) trip class is implemented to protect
the internal contactors in the product from
overheating.
20
Y
10000
1000
100
1
2 0.1
3
4
Pos.
6.0 7.0 8.0 9.0 X
Y
X
1
2
rated
3
4
5
6
Full-load current is set to 10 [A] and trip class 20 is
selected.
•
•
The contactor is worn out
LC 231 has a wear-out counter for the contactor(s)
which are based on the actual current when the motor
is switched off by the protection function.
When 90 % of the estimated wear-out for the
contactor is reached, the warning code 220 appears
on the operating panel. In Grundfos GO Remote, the
warning Contactor wear out appears.
When 100 % of the estimated wear-out for the
contactor is reached, the alarm code 220 Contactor
wear out appears on the operating panel and the
controller will not be able to start the pumps.
The pump is blocked
To prevent that the contactor gets worn out too fast if
the pump is blocked, a maximum number of restarts
are allowed by the controller. Maximum number of
blocked motor restart can be set from 1 to 3 via
1
10
1
10 20 30 40 50 60
Description
Trip time [s]
Current [A]
CCP
Class 30
Class 20
Class 10
Class 5
CCP + Class 20
Motor overload. When the motor is overloaded
with 15 [A], it will take ~800 seconds to trip the
motor protection when trip class 20 is selected.
The pump is blocked. If the pump is blocked and
the motor has a locked-rotor current specified to
65 [A], it will take approximately 1 second to trip
the motor protection due to the contactor-current
protection.
2
3
4
5
6
70 80 X