Current Limiting - JUMO 709061/8-01-032 Operating Manual

6.7 Current limiting

H
Function
Default setting
V1.04/EN/00561071 [Thyristor Power Switch TYA 201]
Current limiting is only possible for power controllers with load current
measurement, i.e. in the order details, subordinate control I, I
010 in the order code), or P (code 001 in the order code) must be se-
lected.
Current limiting is implemented via phase-angle control. It therefore
only operates permanently in phase-angle operation mode.
If burst-firing operation is active, current limiting only operates in the
soft start phase if "With phase angle control" is selected as the soft
start type.
In a three-phase economy circuit, only the current in the strand of the
master power controller is limited to the configured value. As a result
of the economy circuit, significantly greater load currents can flow in
the other two phases.
Current limiting prevents overcurrents in the load current circuit. It limits the
load current independently of the load resistance and the setpoint value to the
required current limit value by enlarging the phase control angle, if necessary.
Current limiting is unavoidable for heating elements with a high positive tem-
perature coefficient, such as Kanthal-Super, for example. Without current limit-
ing, the load current would accept inadmissibly high values when such heating
elements are in a cold state.
Current limiting is not activated.
If necessary, current limiting must be switched on in the configuration level.
v Chapter 5.1.2 "Power controller"
The current limit value can be adjusted both in the configuration level or in the
operator level. In the operator level, it can be adjusted during operation.
6 Special device functions
2
(code
91