45
11. Speed search and Base Block function
Pr.79 to Pr.82 are used to define the inverter's speed searching characteristics for restart process.
The Speed Search function may be initiated by two methods:
By Digital Input to initiate the speed search process
Let DIx(8), selects "Base Block" function to any Digital input. If DIx(8) is ON, then the inverter will disable IGBT output
causing the motor
FREE RUN
to stop.
When DIx OFF again, the inverter will still remain in the BLOCK state for a period of time defined in the parameter
BASE
BLOCK TIME (Pr.36)
. After the period of BASE BLOCK TIME, Then the restart process begins.
Power comes back normal after UP/OP alarm to initiate the speed search process
LET Pr.34 = 1, enables UP/OP restart function. If "UP" or "OP" alarm appear while inverter running, Then the inverter will
disable IGBT output causing the motor FREE RUN.
When Power come back to normal again, the inverter will still remain in the BLOCK state for a period of time defined in
the parameter
BASE BLOCK TIME (Pr.36).
After the period of BASE BLOCK TIME, Then the restart process begins.
PARAMETER
FUNCTION
DESCRIPTION
Pr.79
RESTART TYPE
SELECT RESTART TYPE
Pr.80
RESTART STALL LEVEL
STALL LEVEL WHILE RESTARTING
Pr.81
RESTART DEC TIME
DEC TIME WHILE SPEED SEARCH
Pr.82
VOLTAGE RECOVER TIME
VOLTAGE INCREASING RATE WHILE RESTARTING
Pr.79=0: No restart speed search process. Inverter will start from Pr.04.
Pr.79=1: Speed search begins from previous running frequency.
Pr.79=2: Speed search begins from UPPER LIMIT frequency (Pr.15).
Pr.79=3: Speed search begins from SET SPEED.
BB
Pr.36
Hz
Vout
*
Pr.82
Pr.81
Speed Match
time
time
time
time
Irms
Pr.80 (PDE=150%)
*Note: Pr.79 selects the search start frequency.
After BASE BLOCK TIME, the following steps describe the speed search process:
l
Send out a frequency Hz which is selected by Pr.79, and Let Vout =0.
l
Maintain the initial frequency, and increase the output voltage Vout according to the rate defined by Pr.82. During
this period, monitor the current until it reaches the level defined in Pr.80.
l
Use Pr.81 as deceleration rate to decrease the output frequency Hz and output voltage Vout. Wait until Irms is less
than Pr.80 that means now the inverter output frequency matches the motor speed.
l
Now the inverter output frequency can start ramp to desired target frequency.