Parrallel Generators > Stepup Transformers Setup

Hi !!

I have attached a sketch for grounding setup for parralleling 3 LV generators with stepup transformers.

Can anybody comment on pros and cons of this arrengement of earthing, and any suggestions/comments about choice of transformers are appreciated.


Cheers.

Inverter Duty Transformer

Hi !!,

We have a project to make a VFD based panel for a 2080 volts 60hz 250 hp submersible pump ( 300 metres deep).

The vendor is proposing a 380 volts VFD of rated capacity and a inverter duty Autotransformer to stepup the output of drive to 2080 volts.

I find it a bit odd, to put a stepup Auto-transformer in between the drive and the motor.

I recommended a 2080 volts rated VSd and to put the transformer on the line side.

The available supply is 380 volts 60 hz.

Is it Ok to put a Auto-transformer at the output of drive?

Any thoughts?

Contactor At Load Side

I have seen panels with contactors on load side (output) of VSd, and some panels with contactors on both line(input side) and Load side of VSd.

I personally do not use any contactors ( Load/line) for VSD.

What are advantages/disadvantages of using contactors at the output and input of VSD?

Any thoughts?

Voltage Rating Of Vsd

AC Drives are sold with voltage ratings and HP ratings ,

now, my question is will a 40 hp 460 volts 60hz variable speed drive be suitable to be used in a place having 380volts 60 hz power supply to drive a 40 hp/380 volts motor.

I feel drive has to be derated by 17%.

Any thoughts..

Variable Speed Drives And Stray Voltages In Dairy Farm

Gentlemen,

There is a lot of fog and theories about Variable speed drives creating stray voltages and causing problems to cows in dairy farms.

I know cows are sensitive to stray voltage, but do VSd's cause such voltages ?.

What are the methods to avoid/measure these voltages?

Any thoughts/ideas are appreciated.