Beckhoff KL2791 Series, Documentation

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Mounting and wiring
KL2791 20 Version: 2.0.0
3.3 Notes on operation
Intended use
Mains supply
The KL2791 speed controller terminal is designed for direct mains operation (230 V
AC
/120 V
AC
) without up-
circuit transformer.
Attention
No upstream transformers!
Excessive inductances in the supply line for the speed controller terminal lead to destruc-
tion of the speed controller terminal in the event of a short circuit!
Automatic load detection does not operate reliably with an upstream transformer.
Attention
Do not mix capacitive and inductive loads!
Capacitive and inductive loads must not be mixed at a speed controller terminal!
Setting mode
Attention
Use the correct setting mode!
Full-wave control:
As a basic principle, full-wave control is suitable for single-phase rotary AC motors.
Leading edge phase control:
In motors that are very dynamic, full-wave control can lead to unbalance. The leading edge
phase control operating mode is designed for such motors. It ensures smooth operation, al-
though under certain circumstances it may adversely affect the service life of the motor.
Mixed control:
Mixed control provides strikes a balance between full-wave control and leading edge phase
control and therefore offers a compromise between smooth operation and motor protection.
Minimum interruption of mains supply
Attention
Minimum mains interruption
Any interruption of the mains supply for the speed controller terminal may not be shorter
than 3 seconds (e.g. switching off and on again of an automatic circuit-breaker)!
With shorter interruptions, the speed controller would not lose its mains synchronization
and may operate the load with the wrong control mode (due to the switch-on edge).
With wound transformers, this may lead to destruction of the speed controller terminal!