ABB UMC100-FBP Technical Description page 43

Universal Motor Controller
UMC100-FBP
Technical Description
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:
Example:
The start-up phase ended at T1. At T2 the current increases above the high current warning level I
a period longer than the high current warning delay time t
set.
At T3 the current also increases above the high current trip level I
specified high current trip delay time t
there long enough to trigger an overcurrent trip that finally stops the motor.
I/I [%]
e
I
hctl
I
hcwl
I
SE
I
e
High Current Warn
---------------------------------------/===========================================================
High Current Trip
-------------------------------------------------------------------------------/===================
 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
FieldBusPlug / Issue: 03.2012
I>I
hcwl
I/I [%]
e
I>I
hctl
After Start-up
 Signal flow of the high current protection function.
hctd
T2
T1
& T
hcwd
& T
hctd
. Therefore the high current warning signal is
hcwd
hctl
. Then at T4 the current rises again above the trip level and stays
T3
t
hcwd
t
hctd
• High Current Warning Level
• High Current Warning Delay
- 43 -
High Current
Warning
High Current
Trip
but only for a period shorter than the
I : High current trip
hctl
delay time
I : High current warning
hcwl
delay level
I : High current trip delay
hctd
I :High current warning
hcwd
delay
I : Nominal current
e
I : Current defining
SE
the end of the start-
up period
T4
t
hctd
UMC100-FBP
for
hcwl