Learning Protection Features
Speed Command Loss Setting Details
In situations when speed commands are lost, the inverter can be
configured to operate in a specific mode:
The speed command immediately becomes the
operation frequency without any protection
function.
The inverter blocks output. The motor performs
in free-run condition.
The motor decelerates and then stops at the
time set at Pr.07 (Trip Dec Time).
The inverter calculates the average input value
for 10 seconds before the loss of the speed
command and uses it as the speed reference.
The inverter calculates the average output value
for 10 seconds before the loss of the speed
command and uses it as the speed reference.
The inverter operates at the frequency set at Pr.
14 (Lost Preset F).
Pr.15 AI Lost Level,
Pr.13 Lst Cmd Time
Configure the voltage and decision time for speed command loss when
using analog input.
Based on the values set at In.08 and In.12,
protective operation starts when the input signal
is reduced to half of the initial value of the
analog input set using the speed command (Frq
code of Operation group) and it continues for
the time (speed loss decision time) set at Pr. 13
(Lost Cmd Time). For example, set the speed
command to 2 (V1) at the Frq code in the
Operation group, and In.06 (V1 Polarity) to 0
(Unipolar). When the voltage input drops to less
than half of the value set at In.08 (V1 Volt x 1),
the protective function is activated.
The protective operation starts when the signal
becomes smaller than the initial value of the
analog input set by the speed command and it
continues for the speed loss decision time set at
Pr.13 (Lost Cmd Time). Codes In.08 and In.12
are used to set the standard values.
In situations where speed commands are lost, set the operation mode
(Pr.12 Lost Cmd Mode) to 5 (Lost Preset). This operates the protection
function and sets the frequency so that the operation can continue.
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