ABB UMC100-FBP - Page 43

- 43 - UMC100-FBP
Universal Motor Controller
UMC100-FBP
Technical Description
FieldBusPlug / Issue: 03.2012
High Current Protection
This function is useful to protect the driven mechanical system from jams and excessive overloads
caused by the equipment or the process.
The high-current function signals a warning when the motor current exceeds a set threshold for a con-
figurable period of time, after the motor start-up. The high current function creates a trip when the current
continuously exceeds a separately set threshold for a set period of time, after the motor start-up.
Block Diagram:
&
I/Ie[%]
I>Ihcwl
Thcwd
High Current
Warning
After Start-up
I>Ihctl
& Thctd
High Current
Trip
 Signal flow of the high current protection function.
Example:
The start-up phase ended at T1. At T2 the current increases above the high current warning level I
hcwl
for
a period longer than the high current warning delay time t
hcwd
. Therefore the high current warning signal is
set.
At T3 the current also increases above the high current trip level I
hctl
but only for a period shorter than the
specified high current trip delay time t
hctd
. Then at T4 the current rises again above the trip level and stays
there long enough to trigger an overcurrent trip that finally stops the motor.
[%]
I/I
e
I
hctl
I
hcwl
I
e
T1
I
SE
---------------------------------------/===========================================================
-------------------------------------------------------------------------------/===================
T2
T3
t
hcwd
t
hctd
t
hctd
T4
 Trend diagram of the motor current over time showing the function of the high current protection
function with the related parameters.
Relevant Parameters:
•High Current Trip Level
•High Current Trip Delay
•High Current Warning Level
•High Current Warning Delay
I
hctl
: High current trip
delay time
I
hcwl
: High current warning
delay level
I
hctd
: High current trip delay
I
hcwd
:High current warning
delay
I
e
: Nominal current
I
SE
: Current defining
the end of the start-
up period
High Current Warn
High Current Trip