4-167
Notes: Speed Search Operation
- The speed search cannot be used when the motor rated power is greater than the inverter rated power.
- The speed search cannot be used when the motor rated power is two inverter sizes smaller than the
inverter currently used.
- The speed search cannot be used in combination with a high-speed motor.
- If speed search function is used and the control mode is in V / F mode, it is necessary to perform a static
auto-tune.
- If speed search function is used and the control mode is in SLV mode, it is necessary to perform a
rotational auto-tune. Perform a static auto-tune when using long motor leads.
Speed search uses current detecting. Use parameter 07-24 to select detection direction.
07-19: Speed Direction Search Operating Current
- Used in bidirectional speed search only (07-24 = 1).
- Set bidirectional current level.
- Increase value if speed search is not successful at low speeds (above 5Hz)
Note: If value is too high may cause DC braking effect.
07-20: Speed Search Operating Current
- Can be used for bidirectional (07-24 = 1) or unidirectional (07-24 = 0) speed search.
- Sets speed search current Level.
- The set value must be lower than the excitation current (02-09) and must equal to the no-load current. If
the no-load current is unknown it is recommended to set value at 20%.
- Excessive speed search current will cause inverter output to saturate.
- It is recommended to use speed search in case of a momentary power loss. Increase the minimum base
block time (07-18) in case of an over-current condition.
07-21: Integral time of speed searching
- Can be used for bidirectional (07-24 = 1) or unidirectional (07-24 = 0) speed search.
- Set the integral time during speed search.
- If OV occurs, increase the set value to increase the speed search time. Decrease the value if a quick
start is required
07-22: Delay time of speed search
- Use delay time when using a contactor on the inverter output side.
- The inverter speed search starts after the delay time expires.
- Speed search delay time is disabled when set to 0.0 sec. (07-22 = 0.0)
07-23: Voltage recovery time
- Sets the voltage recovery time.
- Sets the time for the inverter to restore the output voltage from 0V to the specified V/f level after speed
search function is completed.
07-24: Direction-Detection Speed Search Selection
07-24=0: Disable Direction-Detection Speed Search
Speed search is executed using speed search operating current defined in parameter 07-20. In case
speed search is not successful (e.g. motor speed is too low) a speed search time-out warning is displayed.
Set 07-19 to value greater than 0 to enable DC braking at speed search if a time-out occurs frequently.
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