Catalogue - VLT® Product Catalogue - Danfoss VLT Drives

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Frequency inverter, Servo drive, Starter, Harmonic filter, Drive motor

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VLT® Power Options du/dt filter

du/dt filters reduce the du/dt values on the motor terminal phase-to-phase voltage - an issue that is important for short motor cables.

The du/dt filters reduce the motor insulation stress and are recommended in applications with risk of flashover.

Compared to sine-wave filters, du/dt filters cut off frequencies above the switching frequency. Having small inductance and capacitance, the price of the filter is lower.

Voltage overshoots and voltage peaks

Subject to voltage pulses, voltage peaks occur in the choke every time switching takes place. The higher inductance the higher voltage peaks causing stress situations in the winding insulation of the connected motor.

Owing to the cable impedance, the du/dt stress - in the case of longer motor cables - is reduced to less problematic values.

Despite the reduced du/dt owing to the cable impedance, this does not result in any significant stress relief for the motor, since now, the increased voltage amplitudes represent the dominant stress factor.

Advantages

• Protects the motor against voltage peaks and high du/dt values hence prolongs the lifetime of the motor

• Allows theuseofmotorswhichare not specifically designed for converter operation, for example in retrofit applications

Reduced size, weight and price compared to the sine-wave filters

• Possibility of connecting shielded cables with included decoupling plate

• Compatible with all control principle including flux and WC+

• Parallel filter installation is possible with applications in the high power range

The perfect solution for:

• Applications with short motor cables (up to 150 m)

• Applications with older motors

• Aggressive environments

• Applications with frequent braking

Range

3 x 200 - 500 V, 24 - 2300 A 3 x 525 - 690 V, 28 - 1350 A

Enclosures

IP 00 and IP 20 enclosure in entire power range


Mounting • Side by side mounting with the drive	Features	Benefits
Mounting • Side by side mounting with the drive	• Reducesdu/dtstresses	• Increases motor service interval
• Filters wall mounted up to 115 A and floor mounted above that size	• Lowersthemagneticinterference propagation on surrounding cables and equipment	• Trouble-free operation

VIT

THE REAL DRIVE

VLT® Product Catalogue - Danfoss VLT Drives - #1

Frequency inverter, Servo drive, Starter, Harmonic filter, Drive motor