What the heck is a stored energy breaker?
- Thread starter steve66
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Off hand, thinking it's normally a draw out breaker in a switchboard. The "stored energy" that is released is when you press that close button, and it scares you good time as the spring driven contacts slam in for solid contact.
drbond24
Senior Member
- Location
- Barboursville, West Virginia
It is a breaker with springs inside that slam the contacts closed for you. When the springs are compressed they store mechanical energy.
Like Rockyd said, be ready when you close it. It makes a bit of noise.
Like Rockyd said, be ready when you close it. It makes a bit of noise.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
It's not necessarily associated only with draw-out gear, but yes, the breaker has a wound spring mechanism that closes or opens the contacts really fast. All breakers have a spring assist mechanism of some sort because closing or opening the contacts too slowly can allow a destructive arc to jump the gap as the contact surfaces approach each other or separate. In a small breaker, there is a small spring and a simple knee joint that snaps over. But you may have noticed that the bigger the breaker is, the harder t is to get it to snap over. At some point, it gets too hard for humans to do it. So they put in a wound spring and a ratcheting mechanism to wind, or "charge" it, then a push button to release the ratchet and close it. The charging mechanism is usually a handle that moves up and down, hence the term "pumping the breaker". Once closed, the breaker typically has an internal AC powered motor that winds it again for being ready to open it as well.
For the truly lazy people out there, really expensive breakers provide motorized operation both ways .
For the truly lazy people out there, really expensive breakers provide motorized operation both ways .So what other options would there be for a 3000 A/ 480V breaker?
Different types of breakers is something I have never felt I knew very well. Are there any good documents someone could recommend that covers the basic types of circuit breakers?
Steve
Different types of breakers is something I have never felt I knew very well. Are there any good documents someone could recommend that covers the basic types of circuit breakers?
Steve
zog
Senior Member
- Location
- Charlotte, NC
For 480V 3000A it will almost always be a stored energy breaker. Back in the 60's a solenoid was used for this size breaker in leiu of springs but that style became extinct by the 70's due to slow closing times and high failure rates. Now most all are stored energy using springs. The future will see the end of springs and move towards magnetic operations, we are developing some of this now.
A stored energy breaker could be Manually Operated (MO), which requires the operator to manually charge the springs but for 3000A Electricaly Operated (EO) is more common where a charging motor (Similar to a drill motor) charges the springs, then the operator either manually closes it by pushing a button to release a latch that discharges the closing springs to close the contacts or the operator can energize a close cail to do the same thing.
Most 480V breakers in this class are draw out air power breakers but could also be a VCB.
A stored energy breaker could be Manually Operated (MO), which requires the operator to manually charge the springs but for 3000A Electricaly Operated (EO) is more common where a charging motor (Similar to a drill motor) charges the springs, then the operator either manually closes it by pushing a button to release a latch that discharges the closing springs to close the contacts or the operator can energize a close cail to do the same thing.
Most 480V breakers in this class are draw out air power breakers but could also be a VCB.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
At 3000A low voltage you have a few choices:
2 mfrs that I know of have Molded Case Circuit Breakers (MCCB) that go up to 3000A; Square D and Siemens. (there may be more, I just haven't been exposed to them).
Typically though, 2000A and up is where people tend to go with Power Breakers (PB) which are the stored energy type and come in 2 flavors; Insulated Case (ICCB) or Air Circuit Breakers (ACB) . All of the major manufacturers offer one or the other of these (or both). ICCBs use a plastic case, similar to an MCCB, but much larger and more versatile. They can be put into draw out frames in LV switchgear or mounted directly into panelboards where MCCBs are used as branches but need a large main breaker. ACBs are similar except then always come in a metal frame for draw-out gear.
You can also use Medium Voltage Vacuum Circuit Breakers (VCB) on low voltage, but they are really no smaller than PBs. Their only advantage in low voltage is that the contacts are sealed in vacuum bottles and if you have a lot of contamination they will last longer.
The biggest differences between MCCBs and PBs is that in a coordinated scheme, PBs are designed to handle much higher currents for longer times than MCCBs are. PBs are designed to be easily serviced and even rebuilt, whereas MCCBs are not (although people do it). There is however a skill set involved in choosing high energy coordinated power protection and if you are not trained in it, that is something best left to someone who is qualified.
2 mfrs that I know of have Molded Case Circuit Breakers (MCCB) that go up to 3000A; Square D and Siemens. (there may be more, I just haven't been exposed to them).
Typically though, 2000A and up is where people tend to go with Power Breakers (PB) which are the stored energy type and come in 2 flavors; Insulated Case (ICCB) or Air Circuit Breakers (ACB) . All of the major manufacturers offer one or the other of these (or both). ICCBs use a plastic case, similar to an MCCB, but much larger and more versatile. They can be put into draw out frames in LV switchgear or mounted directly into panelboards where MCCBs are used as branches but need a large main breaker. ACBs are similar except then always come in a metal frame for draw-out gear.
You can also use Medium Voltage Vacuum Circuit Breakers (VCB) on low voltage, but they are really no smaller than PBs. Their only advantage in low voltage is that the contacts are sealed in vacuum bottles and if you have a lot of contamination they will last longer.
The biggest differences between MCCBs and PBs is that in a coordinated scheme, PBs are designed to handle much higher currents for longer times than MCCBs are. PBs are designed to be easily serviced and even rebuilt, whereas MCCBs are not (although people do it). There is however a skill set involved in choosing high energy coordinated power protection and if you are not trained in it, that is something best left to someone who is qualified.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Typically yes. But read the description again. The motor is used to CHARGE the mechanism, not operate it. So if you have power, the spring is charged immediately after it is discharged so that it is ready again. If you have no power, you can still open the breaker by virtue of the stored energy in the spring, but if you want to close the breaker again while power is off (and why would you?) then you have to pump it by hand.
zog
Senior Member
- Location
- Charlotte, NC
A control power source internal to the switchgear, usually 120VAC or 125VDC, although there are many different sources used.
Yep, usually requires a seperate "maintenence handle" to do so. However, usually the closing springs charge right after after the breaker closes, so if power is lost at a later time the springs are already charged and ready for the next close operation.
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