Circutor AFQm Series, Instruction Manual

Page: 41 / 108

41 Instruction Manual
AFQm
4.4.- RESONANCE DETECTION
The
AFQm
acts as a current, frequency and variable amplitude generator. This current circu-
lates via the path of least impedance, which should be the mains.
In certain cases, there may be a load that provides less impedance than the mains, in which
case a resonance phenomenon will be produced with that load. The AFQm has a detection
system for resonance with loads, which automatically deactivates the harmonic that causes
that resonance.
In environments with a high level of short-circuit impedance of the mains and a high level of
voltage THD , a condition may occur that the filter erroneously detects as resonance.
In such conditions, the filter action improves the current THD , which causes an improvement
of the voltage THD . The improvement of the voltage THD causes the loads to increase their
consumption, producing a deterioration of the current THD . The user will see that the current
THD is worse when connecting the filter, or that the filter does not correct the current THD as
expected. In addition, the filter detects an increase in the current when correcting the current
THD , which it understands as a resonance, thus activating the protection elements.
If the installation behaves in this way, contact the TAS (Technical Assistance Service) to carry
out the necessary checks to deactivate the resonance alarm safely.
4.5.- SELF-DIAGNOSIS
The device is fitted with a self-diagnosis system. The device checks the integrity of the hard -
ware and software control elements when starting up. This analysis is carried out according to
IEC60730
.
This system ensures the device remains in a safe state in the event of failure. The user is alert-
ed to the failure thanks to an on-screen message and it is also found in the Modbus register.
This type of failure indicates damage or degradation of any of the control and process elements,
both hardware and software. Turning off the device and contacting
TAS
is recommended when-
ever this alarm comes about.