Inst. Breakers Sizes for a 150HP Motor

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MrJLH

Senior Member
Location
CO
Been thrown a curve ball and I'm second guessing myself.

I had a breaker fail that powers a 150 HP pump located in a NEMA 7 enclosure so of course replacing this is going to be a pain.

What is/was installed is a GE instantaneous 400A breaker set at 2200A. (Breaker adjustable range is 1200-4000A)

Unfortunately the breaker that is currently installed is obsolete but a suppler has a similar that may work. What is recommended is a another GE instantaneous 600A breaker of the same model number (Breaker adjustable range is 1000-3000A )

Does this make sense? My thinking is any size breakers can be used along as the trip setting is with in NEC 430.52?

Thanks
 
I

Ingenieur

Senior Member
Location
Earth
I see no issue
480 vac assumed
although the 2200 seems high for 150 HP >1200 %
what type of pump? assuming starts under no load
do a quick sc calc at the motor
wire size? length?
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
No, won't matter at all electrically, all you need is to have the range of adjustment you need to get to the setting you know was working.

A more LIKELY problem might be making the breaker mount correctly so that it interfaces with the operating handle mechanism in your NEMA 7 enclosure! 400A to 600A is usually a frame size change, which might ALSO give you fits for maintaining legal wire bending space from the terminals to the enclosure wall.

I'd try harder to find an exact replacement. "Breaker Brokers" often have old out-of production breakers and many of them are what's called "NOS" for New Old Stock, meaning they are brand new, but have been sitting on a shelf as a spare part somewhere until the broker bought them.
 
M

MrJLH

Senior Member
Location
CO
Ingenieur said:
I see no issue
480 vac assumed
although the 2200 seems high for 150 HP >1200 %
what type of pump? assuming starts under no load
do a quick sc calc at the motor
wire size? length?
Click to expand...

Yep 480!
Problem with my facility is that I find breakers all the way turned up. I only find them when an entire switch rack system trips out after a down steam motor fault.
Pump is a vertical bowl pump.
FLA is 173A

Just hit bump in the road. Looks like the wire size is only #2/0
 
Last edited:
Besoeker

Besoeker

Senior Member
Location
UK
MrJLH said:
Been thrown a curve ball and I'm second guessing myself.

I had a breaker fail that powers a 150 HP pump located in a NEMA 7 enclosure so of course replacing this is going to be a pain.

What is/was installed is a GE instantaneous 400A breaker set at 2200A. (Breaker adjustable range is 1200-4000A)

Unfortunately the breaker that is currently installed is obsolete but a suppler has a similar that may work. What is recommended is a another GE instantaneous 600A breaker of the same model number (Breaker adjustable range is 1000-3000A )

Does this make sense? My thinking is any size breakers can be used along as the trip setting is with in NEC 430.52?

Thanks
Click to expand...
The instantaneous starting current is likely to be upwards of 1,000A. If the breaker has an instantaneous trip you may need to set it at around 1,500 A.
 
zog

zog

Senior Member
Location
Charlotte, NC
MrJLH said:
Been thrown a curve ball and I'm second guessing myself.

I had a breaker fail that powers a 150 HP pump located in a NEMA 7 enclosure so of course replacing this is going to be a pain.

What is/was installed is a GE instantaneous 400A breaker set at 2200A. (Breaker adjustable range is 1200-4000A)

Unfortunately the breaker that is currently installed is obsolete but a suppler has a similar that may work. What is recommended is a another GE instantaneous 600A breaker of the same model number (Breaker adjustable range is 1000-3000A )

Does this make sense? My thinking is any size breakers can be used along as the trip setting is with in NEC 430.52?

Thanks
Click to expand...

What is the model # of the breaker you need? What type of failure occurred?
 
I

Ingenieur

Senior Member
Location
Earth
MrJLH said:
Yep 480!
Problem with my facility is that I find breakers all the way turned up. I only find them when an entire switch rack system trips out after a down steam motor fault.
Pump is a vertical bowl pump.
FLA is 173A

Just hit bump in the road. Looks like the wire size is only #2/0
Click to expand...

the wire is an issue
how long?
source to starter
starter to pump
xfmr serving the pump kva

the way we set them
set up at 10 times 1700 A
using a peak recording amp clamp start it a few times
if it trips turm it up in 100% increments
use 120% x highest reading
 
M

MrJLH

Senior Member
Location
CO
Ingenieur said:
the wire is an issue
how long?
source to starter
starter to pump
xfmr serving the pump kva

the way we set them
set up at 10 times 1700 A
using a peak recording amp clamp start it a few times
if it trips turm it up in 100% increments
use 120% x highest reading
Click to expand...

edit to last: Wire is a #3/0 about 15ft away from the starter to the pump.

The enclosure which is fed from a (don't judge) up stream splice box , and another upstream splice box (tapped twice) and finally a 600A 480V breaker off another switch rack which is eventually fed from a 2,000KVA 13.2/480V XFMR. I would say from the source to the breaker about 400'.
size 5 starter
 
I

Ingenieur

Senior Member
Location
Earth
MrJLH said:
edit to last: Wire is a #3/0 about 15ft away from the starter to the pump.

The enclosure which is fed from a (don't judge) up stream splice box , and another upstream splice box (tapped twice) and finally a 600A 480V breaker off another switch rack which is eventually fed from a 2,000KVA 13.2/480V XFMR. I would say from the source to the breaker about 400'.
size 5 starter
Click to expand...

assuming a pu Z of 5% and 500 LF of 3/0 you should still have 4500-5500 i fault at motor
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
If you can't get an instantaneous only breaker in that frame size you could potentially replace it with a regular thermal magnetic breaker of the same style.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
zog said:
If only we knew what that was
Click to expand...
Everything in that size range that GE has made since the '70s is still available. Maybe more expensive than their equivalent Spectras, but you can still order them right out of the catalog. If it's the TJC 400A frame Mag Break that has been around since I started in this business, you can still order it.

I'd bet a dollar to a doughnut that it's an old GE TBC or TL-M 600AF mag-only breaker. It's the only thing in that size range I'm aware of that GE has obsoleted that would have been used in a NEMA 7 starter rack. Some breaker broker will have one, somewhere and if you have one in your area, they have an on-line system called PEARL that they use to check inventory among them all across the country for old obsolete breakers like that.
 
zog

zog

Senior Member
Location
Charlotte, NC
Jraef said:
Everything in that size range that GE has made since the '70s is still available. Maybe more expensive than their equivalent Spectras, but you can still order them right out of the catalog. If it's the TJC 400A frame Mag Break that has been around since I started in this business, you can still order it.

I'd bet a dollar to a doughnut that it's an old GE TBC or TL-M 600AF mag-only breaker. It's the only thing in that size range I'm aware of that GE has obsoleted that would have been used in a NEMA 7 starter rack. Some breaker broker will have one, somewhere and if you have one in your area, they have an on-line system called PEARL that they use to check inventory among them all across the country for old obsolete breakers like that.
Click to expand...

We ship dozens of breakers a day to guys using that on line system lol
 
I

Ingenieur

Senior Member
Location
Earth
Jraef said:
Everything in that size range that GE has made since the '70s is still available. Maybe more expensive than their equivalent Spectras, but you can still order them right out of the catalog. If it's the TJC 400A frame Mag Break that has been around since I started in this business, you can still order it.

I'd bet a dollar to a doughnut that it's an old GE TBC or TL-M 600AF mag-only breaker. It's the only thing in that size range I'm aware of that GE has obsoleted that would have been used in a NEMA 7 starter rack. Some breaker broker will have one, somewhere and if you have one in your area, they have an on-line system called PEARL that they use to check inventory among them all across the country for old obsolete breakers like that.
Click to expand...

commonly used in mining
http://www.geindustrial.com/products/circuit-breakers/mag-break-motor-circuit-protector

some of the issue may be ge was bought by abb
they stopped mfg new stuff and began liquidating inventory for close to a year to make the books look better and in anticipation of the sale
they will use rebranded abb stuff
eg, mif relays will no longer be available
they recently requested all their equip approvals be transferred to another entity, not abb
 
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