×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

VFD heat dissippation

VFD heat dissippation

VFD heat dissippation

(OP)
I am working with VFD. The heat loss from VFD is 200KW.plus other heat loss. The total heat loss is about 230Kw. Does it mean the HVAC has to sized to be larger than 230Kw?

Thanks

RE: VFD heat dissippation

It depends on what the HVAC system is supposed to do and what you mean by "sized larger than 230 kW"  .  Not enough data.  As the EE, one would generally provide the heat loss data to the HVAC engineer and then let them design the HVAC system.  

RE: VFD heat dissippation

Is the VFD output power 200kW and the input power 230 kW?

RE: VFD heat dissippation

If you have a VFD losses of 200kW including motor losses, the motor must be rated about 2500kW (3300 Hp), twice that it the 200kW is the losses for the VFD alone. Is that what you are asking about?

RE: VFD heat dissippation

That! is a lot of loss.

I would think you save a bundle by just turning the air over instead of mechanically moving the heat.  Yuck.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: VFD heat dissippation

(OP)
VFD is 3500HP. As a matter of fact, electrical power for HVAC won't be that much. I asked one of my friends, who is HVAC engineer, to size the HVAC. It turned out to be only 50kW, considering the building size and room temperature diferences.  

RE: VFD heat dissippation

Hamid
8% losses in the VFD alone? That seems a poor dive efficiency to me. In fact, even if it included the motor losses I think it would be a lot. Is that the data from the manufacturer? Is the drive system continuously running?

RE: VFD heat dissippation

A lot of MV drives now are 18 or 24 pulse so they have phase shifting transformers built-in. A lot of those losses are in the transformers.

RE: VFD heat dissippation

Hey Jeff are these transformers 'real' isolation transformers?  Or are they just 'I's?  Are they strange in any way?

I am having a problem picturing a truckload of transformers gathered around some relatively small VFD.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: VFD heat dissippation

Keith,

The one's I've seen use one special multi-winding transformer with multiple secondary windings.  

RE: VFD heat dissippation

Lots of other stuff here, but scroll down to Figure 3 for a graphical representation.

Phase shifting transformer paper

And then to see how this translates to the real world of MV drives, go to page 9 of this brochure.
Robicon perfect harmony drive brochure

PS: They are not exactly "little" drives we are talking about here.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources