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 Post subject: Regenerative Drive Contributions to Upstream Fault
PostPosted: Wed Nov 16, 2016 2:43 pm 

Joined: Tue Apr 17, 2012 9:17 am
Posts: 10
Is there any information on what a regenerative drive will allow a motor to contribute to an upstream fault? I know ANSI has some standards for motor contributions based on <50HP or >50HP for across the line starters. We have some DC motors with regen drives connected to a 480VAC system and I want to model the contributions of the motors on the upstream switchgear. A few of these motors are 500HP or bigger.

We used to use Easypower and I remember that had an option for selecting if your drive was Regen or Non-Regen, and that would affect the contributions. But the contributions of a regen drive was less than across-the-line for the same size motor.

We've since switched to etap, and their drive model doesn't have a re-gen option. Not to mention they don't have a real clean way to model a DC drive on an AC system.

I'm thinking there's a way I can model the load and the short circuit calculations if there's some sort of impedance multiplier for re-gen drives for the 1/2 cycle or 5 cycle short circuit.


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 Post subject: Re: Regenerative Drive Contributions to Upstream Fault
PostPosted: Fri Feb 10, 2017 2:41 am 

Joined: Thu Apr 02, 2015 11:39 pm
Posts: 2
Location: New Jersey
Sorry, but why did you switch to ETAP???


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 Post subject: Re: Regenerative Drive Contributions to Upstream Fault
PostPosted: Sat Feb 11, 2017 10:58 am 
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Joined: Tue Oct 26, 2010 9:08 am
Posts: 2174
Location: North Carolina
Look in the information on the drive. They will give you a maximum current draw. Worst case, the transistors are rated for RMS ratings so they can't exceed approximately 200% of their maximum name plate ratings or the transistors turn into very fast fuses (blow up).


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