Omron VARISPEED F7 User Manual

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Speed Search Retry Function
With the calculation type speed search the speed is detected with the motor residual current before a voltage is
applied to the motor. In case of very low current values (as with special motors) the detected speed can differ
from the actual speed of the motor. This results in a very high current when the voltage is applied as the
inverter output frequency differs from the actual motor frequency.
Enabling the Speed Search Retrials.
The speed search retry function is enabled when b3-19 number of speed search retrials must be set to a value
different from 0 (b3-19K0).
When the voltage is applied to the motor and the resulting current is higher than the speed search retry current
level (b3-17) for a time longer than the speed search retry detection time (b3-18) the speed search funciton
will be restarted.
When the speed search function has retried to catch the motor b3-19 times without success an “SER” fault will
occur.
Application Precautions for Speed Calculation Speed Search
When the motor is one or more frame sizes smaller than the Inverter the current might be too small for the
Inverter to detect the speed during speed search. In this case the current detection type speed search should be
used.
 Continuing Operation at Constant Speed when the Frequency Reference
is Lost
The frequency reference loss detection function detects a loss of the frequency reference signal. If an analog
frequency reference source is selected, a frequency reference loss is detected, when the reference value drops
to less than L4-12 % of the previous value in 400 ms or less.
The operation after a reference loss can be set in parameter L4-05 as follows:
• L4-05 = 0: The inverter operation is stopped.
• L4-05 = 1: The operation is continued at reduced speed using the set value in parameter L4-06 as fre-
quency reference value.
When an fault signal during frequency reference loss shall be output externally, set H2-01 to H2-03 (multi-
function digital output terminal M1-M2, M3-M4, and M5-M6 function selection) to C (frequency reference
lost).
Related Parameters
Multi-function Digital Outputs (H2-01 to H2-03)
Parameter
No.
Name
Factory
Setting
Change
during
Opera-
tion
Control Methods
V/f
V/f with
PG
Open
Loop
Vector
Closed
Loop
Vector
L4-05Operation when frequency reference is missing 0 NoAAAA
L4-06Output frequency adjustment after freq. reference loss 80%NoAAAA
L4-12Frequency reference detection width 10%NoAAAA
Set Value Function
Control Methods
V/f
V/f
with
PG
Open
Loop
Vector
Closed
Loop
Vector
C Frequency reference loss Yes Yes Yes Yes

Omron VARISPEED F7 Specifications

General

Brand	Omron
Model	VARISPEED F7
Category	Inverter
Language	English