Jim1959
Senior Member
- Location
- Longmont, CO
I'm bidding a job with 2 - 4000HP (yes 4000) 4160Volt motors and don't have the FLA rating. How can I at least get an average rating?
MOTOR AMPERAGE
- Thread starter Jim1959
- Start date
- Status
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Use .14 A/HP. Most 2 to 4 pole motors will be lower than that, 6 pole and up may be higher.
So 4000HP assuming 4 pole I would guestimate to be 560A
Also assuming Squirrel Cage Induction Motors. At 4,000HP you are deep in the world in which people often use Synchronous motors, which would be different so make sure of what they are planning on using. If they are unsure (many users are), ask if they know the speed. Synch motors are typically low RPMs.
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4000 x 746 / (sqrt3 4000 0.82) = 525 A
many 4160 motors I see have a rated V of 4000
avg pf x eff ~ 0.82
pg 163
495 to 530 A
http://www.esrmotors.com/Literature/Toshiba/Motors/Catalogs/LVM_Catalog_2013.pdf
$350-400k !
many 4160 motors I see have a rated V of 4000
avg pf x eff ~ 0.82
pg 163
495 to 530 A
http://www.esrmotors.com/Literature/Toshiba/Motors/Catalogs/LVM_Catalog_2013.pdf
$350-400k !
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Jim1959
Senior Member
- Location
- Longmont, CO
thanks guys, those numbers make sense based on the OCP and cable size. I'm bidding based on a previous contractors plans, so trying to double check everything.
I have an Excel spreadsheet that I generated for my own use.
I'd be quite happy for you share it. If I knew how to get it to you.
Anyway, it gives a bit over 500A for your application which is in line with what others have suggested.
FionaZuppa
Senior Member
- Location
- AZ
- Occupation
- Part Time Electrician (semi retired, old) - EE retired.
https://www.ab.com/support/abdrives/documentation/fb/1018.pdf
pf=eff=0.82
533 2-phase
616 3-phase
Baldor advertises ~97% eff and ~87% pf at full load
Baldor 4kv 2250hp LR 1841, FLA 286
pf=eff=0.82
533 2-phase
616 3-phase
Baldor advertises ~97% eff and ~87% pf at full load
Baldor 4kv 2250hp LR 1841, FLA 286
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pf x eff ~ 0.82
the catalog I linked listed the eff 96-97% for a 4000 v 4000 hp motor
0.97 x 0.87 ~ 0.84 close to 0.82
Which, pro rata, would give 508A.
Ragin Cajun
Senior Member
- Location
- Upstate S.C.
In your bid list the amperage value you assume and indicate if the actual nameplate rating is higher, than there will be an up charge. List "type" of motor as well. CYA!
RC
RC
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