Diesel Emergency Generator Amp Load

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Discussion Overview

The discussion revolves around determining the maximum amp load that can be connected to a CAT Standby 650 ekW generator, focusing on the implications of power factor, load types, and the characteristics of three-phase systems. Participants explore theoretical calculations and practical considerations related to electrical loads, particularly motors and lighting.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant suggests using the formula W=V*A for calculating load, questioning if there are additional factors to consider.
  • Another participant discusses the power requirements for a motor, indicating that the generator can supply 650 kW at the shaft and that 813 kVA is needed to power the motor due to reactive power considerations.
  • It is noted that the generator has a built-in power factor of 0.8, leading to a calculation of 813 kVA resulting in 650 kW.
  • Concerns are raised about the implications of different load types, such as motors and transformers, which can have inrush currents and lagging power factors that affect the generator's performance.
  • One participant emphasizes the importance of understanding the generator's standby rating and the stability of loads, mentioning various types of loads that can introduce complexities.
  • A formula adjustment is proposed to account for three-phase systems, suggesting that VA should be used instead of watts for maximum amp load calculations.
  • Another participant highlights the significance of KVA codes for motors, which indicate starting current characteristics that could impact generator performance.
  • One participant points out that voltage drop regulations may affect the current available for specific applications, such as fire pumps.

Areas of Agreement / Disagreement

Participants express various viewpoints on the calculations and implications of power factor, load types, and generator ratings. There is no consensus on the maximum current draw or the best approach to determine it, indicating ongoing debate and uncertainty.

Contextual Notes

Participants mention several factors that could complicate calculations, including the nature of different loads, the effects of inrush currents, and the need for protective relay settings. The discussion does not resolve these complexities.

Who May Find This Useful

Electrical engineers, technicians working with generators, and individuals involved in designing or maintaining electrical systems may find this discussion relevant.

  • #31
psparky said:
You ever notice you can ask advice from three very experienced engineers and get three completely different answers?

At that point...there's really only one question left. What would you do?

I will defiantly not going to invest my money in this project! :)
But if seriously-I will go thru all what we learn, squeeze all juice out of it and send one big and smart e-mail to my boss. thanks god I'm not making desigions here, I'm only a "junior".


jim hardy said:
Lexus - are you sorry now you asked?
but it's fun learning. Thanks to all who contributed -- I've learned things.

I'm sure you'll find the system was well designed.
What a prudent fellow has to do is be sure he doesn't degrade it with his modifications.
To that end he needs to understand the design.

I like to learn new things too. And I'm really glad that here is a people who would help. I’m really appreciate that. I'm try to stay a "prudent fellow" and not going to mess it up by myself.
And... I didn't get your question..
 
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  • #32
lexus31rus said:
I will defiantly not going to invest my money in this project! :)
But if seriously-I will go thru all what we learn, squeeze all juice out of it and send one big and smart e-mail to my boss. thanks god I'm not making desigions here, I'm only a "junior".

And above else...don't forget to tell him you got all your info from the Physics Forums! lol
 
  • #33
""And... I didn't get your question..""

""Sorry i asked" is, over here, a humorous response to a long-winded answer.

I'm hoping you aren't mad at us for the long winded answers.

Have Fun !
and make the responsible design organization be prudent fellows too.

What part of the world are you in?

old jim
 
Last edited:
  • #34
jim hardy said:
What part of the world are you in?

old jim
Hawaii. So, Mahalo and Aloha!
 

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