Optidrive E2 Single Phase Output User Guide V3.10
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5.4.
Single Phase Motor - Boost Starting cycle
In order to provide a reliable method for starting the motor, a special technique is used. The motor is started immediately at rated frequency,
whilst the voltage is ramped from an initial Boost Voltage (set in P-11) to the Motor Rated Voltage (set in P-07) over a Boost Period Duration
(set in P-33). Following the starting boost period, the drive then begins to control the output frequency and speed of the motor. The graphs
below show how this operation works.
In order to achieve reliable starting and optimise the starting method, the following procedure can be used.
1.
The motor must be correctly connected to the drive and safe to operate before using this procedure.
2.
Ensure the motor rated voltage (P-07) and current (P-08) have been correctly programmed in the drive parameters.
3.
Select Extended Parameter Access by setting P-14 = 101.
4.
Set the Boost Period Duration P-33 to the maximum allowed value of 150 seconds.
5.
Start the drive, and display the motor current (press the Navigate button until the display shows “
x.x”
where x is the motor
current)
6.
Check the current value compared to the motor rated current around 3 – 5 seconds after starting the drive
a.
If the current displayed is less than 80% of the motor rated current
i.
Stop the drive
ii.
Increase P-11
iii.
Repeat from step 5
b.
If the current displayed is greater than 90% of the motor rated current
i.
Stop the drive
ii.
Reduce P-11
iii.
Repeat from step 5
7.
The correct boost voltage setting should deliver 80 – 90% of the motor rated current approximately 3 – 5 seconds after enabling the
drive.
8.
Now the Boost Period Duration may be reduced to match the actual time required for the motor to start. The simplest method is to
initially reduce in large steps and monitor the motor behaviour on starting the drive. The ideal boost period will be a few seconds
longer than is required to bring the motor to full speed.
By following this procedure, the motor starting parameter can be optimised to start the motor reliably without excessive starting current.
