575V vs 460V Coordinated Drives for Papermachines 2

[JBUDA54]

I have been on several Pulp and Paper Projects in the recent past where the project direction took the coordinated drives on a 575V power system and the 480V loads consisted of FVR/FVNR/non coordinated VFDs, etc.

Is this a client preference or is there a motive to doing this? I have tried to research this and have not been successful in determining this. Thank you in advance for your comments.

 

[waross]

This may be a combination of availability of new equipment and legacy equipment and spares.
I see petro-chemical plants with a plant utilization of 600 Volts (575 Volts).
But 480 Volts is a common heat trace controller voltage.
So, motors and lighting transformers are 600 Volt based and the heat tracing is 480 Volt based.
Note: I am in Canada where 600 Volts is a standard utilization voltage. This scheme may be more common in Canada.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

For a long time, it was difficult to manufacture good quality 600V drives because the transistors were difficult to make and were much more expensive on a PU current basis. So unles a drive mfr had a substantial market presence in Canada or in the textile industry in the US Southeast, it was an expensive venture. Because other parts of the world began moving to 690V motor and VFD designs, thereby needing higher volume of higher voltage rating transistors, that's no longer true, but the legacy perception persists.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[JBUDA54]

I got an opinion from a seasoned veteran electrical engineer with 30+ years of Pulp and Paper and he said when the copper prices sky rocketed the 575V drives allowed for a cost savings in reducing cable sizing. Since coordinated drives use 1000s of HP the bump in voltage can translate to a decent savings in copper which can be a game changer for some clients. I think that the reason that we are seeing higher low voltage drive systems is a combination of waross, jreaf, and my senior EE's observations.