VFD(MVDrive)

Rattanpk.

I suggest that you do not put your VSD anywhere near your motors/fans in a dusty area. Not sure of the size of drives you are using, but they may require A/C, therefore you could build a very large room/enclosure for the drive and install A/C, however as you ask for the IP rating I guess thats not an option. You must remember that VSD's generate a lot of heat and require cooling, some VSD's have open fans for the electronics. So look at what you want the conditions that you have plan to install the drive in a clean area.

Dear Rattan

Ride through time depends on the value of capacitors connected on DC bus in the VFD. During ride through conditions, energy stored in the capcitor ( 0.5CV sq. ) is used to provide power at output terminals. Hence higher the capacitor value, greater is the available time ( there is also an upper limit too ) Ride through time is to be confirmed by the manufacturer. Due to deterioration in capacitors, this reduces with time. Hence if ride through time is critical & VFD is more than 5-6 years old, then it is also advisable to replace the capacitor bank on the DC bus.

Thanks and regards

Ashok Toshniwal, Bangalore, India.

I never knew that, you learn something new every day

Thanks Brich

How is total power loss ride through time calculated for fans (ID fan of 6.6kV, 1300kW)?

The VFD power supply continues to operate during a momentary power loss and the time of the continuation is called 'ride through time'. In most cases, it is 2 seconds. As Ashok mentioned, the VFD ride through time depends on the value of the capacitor. Maybe, in the future, the VFD manufacturers will use battery instead – but I'm not aware of anything about this.

See the links below. It will help you to calculate the 'Ride Through Time' of a VFD:

https://www.ab.com/drives/techpapers/RideThruWithChonneyCheff.pdf

https://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/vfd_sagimpact.pdf

What will be IP XX, for installing VFD panels in dusty area near ID fans/ Chimney)?

Plenty of information is available for the IP (Ingress Protection, IEC 60529) on the internet. See this link:

https://www.inscapedata.com/pdf/IP68.pdf

-MS