And another good reason to have individual PFC upstream of motor protection devices.
Automatic Cap Banks
- Thread starter raiderUM
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Here's actual data from a 7000kW compressor drive:
You can clearly see the difference between full load torque and virtually no load torque.
Now, how about you reciprocate with motor type and name plate data for your application just to be sure that we are comparing apples with apples?
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mivey
Senior Member
Were you talking about a complete unit including the motor or just the motor alone?
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Mivey...
Are you a disbeliever as well? You should know the nameplate does not list no-load current. Regarding your "motor alone" question; the motor alone, of course. Did you expect a shaft-coupled wound-rotor starting-motor, too?"
Beseoker...
You too should know nameplate does not list no-load curent! However, if you also want proof of its size would a copy of the manufacturer's circle diagram, developed from FAT, suffice? The manufacturer is well known in this world. The FAT data conforms to GE-625, Test Procedures, based on IEEE Std 112-1966! Or will you claim it's outdated?
Regards, Phil Corso
Are you a disbeliever as well? You should know the nameplate does not list no-load current. Regarding your "motor alone" question; the motor alone, of course. Did you expect a shaft-coupled wound-rotor starting-motor, too?"
Beseoker...
You too should know nameplate does not list no-load curent! However, if you also want proof of its size would a copy of the manufacturer's circle diagram, developed from FAT, suffice? The manufacturer is well known in this world. The FAT data conforms to GE-625, Test Procedures, based on IEEE Std 112-1966! Or will you claim it's outdated?
Regards, Phil Corso
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Beseoker...
By "upstream" do you mean upstream of the OL, but downstream of the contactor?
Phil
By "upstream" do you mean upstream of the OL, but downstream of the contactor?
Phil
True, but you have to understand WHO I am working with here. Admin people do not understand anything that I am telling them. They need to see $$$$$$ savings before they go investing a bunch of money into something.
Also, I don't know the exact number but we have a couple thousand Kvar fixed bank units at individual buildings all across campus in addition to the Kvar on the Primary side. These smaller fixed banks range from 100 to 250 Kvar. All of these are already installed, but turned off and just waiting to be used. That is why I'm trying to figure out a good way to control them, so we don;t have to invest a lot of money and resources.
mivey
Senior Member
Disbeliever in what? I'm fact-finding. You mentioned data from a compressor-drive and I was not sure what was included.
OK
No expectations. Just had a simple question.
Yes this does help! Thank you.
The company that built the graphics and organized the BAS system also built me a Trending page. It allows me to track PF from each building so I can see how things change. But I've only been doing this for a couple months.
Yes you explained it very well. Thanks
Thanks for the Heads Up!
There is no way they are going to let me do anything though. I just need to know enough, so that when we do bring someone in to look at things I know if its right or wrong.
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Besoeker...
Since I don't have the "nameplate" data, do you want corroborating documentation?
Phil
Since I don't have the "nameplate" data, do you want corroborating documentation?
Phil
I'm not sure quite what you mean.
But just to be clear, the motor overcurrent protection should be looking at the motor current only.
Just the data recorded at the FAT would be fine rather than anything developed from it.
Can you do that?
Added edit...
This is typical what we would expect from the motor manufacturer.
Real motor. Real application. In this case 6,600kW. Also on a compressor.
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Y'all:
Care to read faithfully what you both have posted? You could be talking about the same thing, IMO.
Bes said "15% was rather atypical of no-load kVA" while Phil said "having a no-load current of 135A and a full-load of 750A"! Anybody can reconcile no-load kVA with No-load current! Discussions may be put to rest right there.
Don't really think so.
kVA.
k is constant. V is constant. Thus kVA is proportional to current in this case. So the ratio of off-load and on-load kVA would be the same as off-load and on-load A.
Unless, of course, the voltage is different on and off load. But then you'd have two different circle diagrams.
Perhaps protagonist Phil could provide Corso confirmation of these constants or contrary ciphering to confound the conventional, customary, and current contention.
.
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Besoeker...
The curves you expect fromthe mfgr will not reveal the INL and IFL values. So I ask again, "... do you want corroborating documentation?"
Phil
The curves you expect fromthe mfgr will not reveal the INL and IFL values. So I ask again, "... do you want corroborating documentation?"
Phil
This is the data that was provided to me at the design stage:
No load current is given and in this case is about 21% (not 15%) and it's the lowest NLC/FLC I've encountered. In 40 years in this field.
Now, since your motor had a FAT, perhaps you could reciprocate by providing the data from that. I see no reason for your seeming reticence about it.
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Beseoker...
Having difficulty attaching Official Test Data (6pgs). HF message says 'size too large'!
Mfg was ASEA (has since joined with Brown-Boveri as ABB) Date was June 1968! Official Data Form lists Inl = 136A, and Ifl = 744A. Thus NL/FL ratio I originally posted has changed from 18 to 18.3!
Any ideas regarding getting full-attachment to you!
Phil
Having difficulty attaching Official Test Data (6pgs). HF message says 'size too large'!
Mfg was ASEA (has since joined with Brown-Boveri as ABB) Date was June 1968! Official Data Form lists Inl = 136A, and Ifl = 744A. Thus NL/FL ratio I originally posted has changed from 18 to 18.3!
Any ideas regarding getting full-attachment to you!
Phil
mivey
Senior Member
Bes & Phil,
So we are getting to around 20% with these big 1,000's of HP motors (kW for Bes). How applicable do you think that is to the OP's 100's of HP? I have seen the 200-500 HP motors in chiller plants before but do not have any specific motor data.
Bes,
You mentioned in an earlier post about not putting PFC behind the motor protection. I have always thought that was where they were recommended since you save on separate protection for the caps. I'm pretty sure I have read that more than once.
So we are getting to around 20% with these big 1,000's of HP motors (kW for Bes). How applicable do you think that is to the OP's 100's of HP? I have seen the 200-500 HP motors in chiller plants before but do not have any specific motor data.
Bes,
You mentioned in an earlier post about not putting PFC behind the motor protection. I have always thought that was where they were recommended since you save on separate protection for the caps. I'm pretty sure I have read that more than once.
Not a lot which is why I took issue with the 15%
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