User`s manual

apfiff09 marine vacon • 167

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7.8.3.1

I/f Control

I/f-control can be used to start the motor using a constant current control. This is useful especially,

if the motor stator resistance is low, which makes the motor current sensitive for u/f-curve tuning at

low speed area. I/f-control is activated by setting AdvancedOptions2.B9 = 1 (P2.10.6) for PM-motors.

Also software modulator is required.

Motor Current

Time [s]

I/f Control

Limit

I/f Start Current

Output Frequency

P2.8.5.6 I/f Current ID1693

NOTE: I/f Current parameter is used for several different purposes.

I/f Control

This parameter defines the current level during I/f control, in percent of the motor

nominal current

Zero position with incremental encoder and Z-Pulse

In closed loop control utilizing the encoder z-pulse, defines also the current level used in

starting before the z-pulse is received to synchronize with.

DC Start Angele identification

This parameter defined DC Current level when Start Angle Identification Time is set

greater than zero. See P2.8.5.5 Start Angle Identification Time.

P2.8.5.7 I/f Control Limit ID1790

This parameter sets the frequency limit for I/f-control in per cent of the motor nominal

frequency. I/f-control is used if the frequency is below this limit. The operation changes

back to normal when the frequency is above this limit with 1 Hz hysteresis.