Older GTO drive efficiency 2

[jraef]

Oh great gurus...
I have been asked to do a comparison between keeping an old (c. 1988) 250HP 460V Relcon VFD which uses GTOs, and installing a new PWM drive in its place. The utility has indicated that they will contribute to the event IF they are shown that there will be at least a 10% improvement in efficiency. I am assuming they mean throughput efficiency, and although the old Relcon drive currently shows a displacement PF of .65, apparently they do NOT care! I am well versed and capable of describing all of the other benefits to the user, but efficiency is unfortunately the only concern of the Utility.

The question I have for you is this: years ago when we were retrofitting older 6-step and current source VFDs with PWM designs on a regular basis, there were several reputable studies available which showed the benefits of doing so, including the improved throughput efficiency. Since I have not been asked this question in probably 10+ years, I no longer have access to any of those papers. Does anyone else have one floating around or can offer some advice (other than a Google or Thomas Register search) in finding one? It would be greatly appreciated.

"Venditori de oleum-vipera non vigere excordis populi"

 

[cbarn24050]

You failed to mention that the drive was allways failing which would make this thread rather pointless since you would replace the drive irrespective of its effiency.

 

[jraef]

What I originally asked for was information anyone had regarding efficiency, not opinions about whether or not the drive should be replaced. I already knew that.

"Venditori de oleum-vipera non vigere excordis populi"

 

[cbarn24050]

oh no you didn't, read the first line of your first post.

 

[jraef]

That is what MY task is, not what I wanted help with. Oh well, this tangent is now very boring and pointless.

"Venditori de oleum-vipera non vigere excordis populi"

 

[jbartos]

Comment on the original posting: The 10% efficiency gain by using PWM principle of VFD in comparison to GTO would be linked to very inefficient GTO based drive. Visit

http://www.robicon.com/library/acrobat/vdfsurv.pdf

which compares drives. Unfortunately, the efficiency is not addressed there quantitatively, only qualitatively.

 

[electricuwe]

chbarn24050,

if you would have read my post dated Mar 28th carefully you would have noticed that I have compared the GTO with twoparalleled IGBTs from the suggested module.