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danesh
December 1st, 2007, 10:37 PM
Hello forum,



I have to starting a 90KW centrifugal electro pump with an 110KW diesel generator, as you know it is impossible with start delta starting and I plan to start it with AC Drive ATV61 Schneider electric. Are there any considerations about this starting? I have to limit current but may be cause limitation in torque! Please help me.



Regards,

Danesh

nettogrisen
December 2nd, 2007, 09:25 AM
I'm not sure what your question is, but I have used alot of ATV61's and I'm pretty sure that you will have no problems with it. It's very easy to set up.

DickDV
December 2nd, 2007, 05:56 PM
The nice thing about AC drives, danesh, is that you can get full rated motor torque for starting without any inrush current. That will be an advantage on your system.

The problems that can show up have to do with poor power quality from the generator. Things like phase unbalance, voltage unbalance, low voltage and high voltage, as well as variations in frequency can all cause a drive to fault. Don't blame the drive if this happens. It likely is the generator's fault.

Lancie1
December 2nd, 2007, 06:11 PM
DickDV,

Would this be a good place to use some type of power conditioner or power filter?

DickDV
December 3rd, 2007, 06:36 AM
I'm not very familiar with the Schneider drives but, if it doesn't come with an internal 3% input line reactor, I would definitely add one. If the low generator voltage is not a problem, I'd probably go with 5% reactance.

That would provide some extra protection against the spikes and blips that so often accompany genset sources.

Thanks for the good observation, Lancie1.

Banker
December 3rd, 2007, 06:56 AM
Hi

Why not use a softstarter?

Banker

DickDV
December 3rd, 2007, 05:52 PM
Banker, a softstarter reduces but does not eliminate the inrush current. Typical with a very soft starting load would be a reduction of half.

So, for example, if you have a NEMA B motor nameplated Code H, inrush across the line would be around six times nameplate FLA. About the best you can hope for with a softstarter would be three times nameplate Fla and that would be with a very easy starting load.

On the other hand, an inverter would walk away with the same load as above with about 40% of nameplate FLA. At 100% FLA, it could accelerate the load much faster than the softstarter still without anything over FLA.

This is entirely due to the inverter starting the motor synchronously whereas the softstarter is not at all synchronous (throwing 60Hz pulses into a stationary motor).