Magnetic forces in the contact area

Magnetic forces in the contact area

The conductors in circuit breaker and the arc are assumed to be threadlike. The anode is
set on the moving contact and the cathode is on the fixed contact. The magnetic flux
density (B) is calculated by using a function of current and contact gap.
The experimental results provide the data of the arc current and the contact gap. The
magnetic flux density (B) is obtained from the magnetic force modeling. The
magnetic forces on arc root are calculated by using the relationship of the arc current,
contact gap and magnetic flux density (B).
At the point at which the arc root moves from contact region with contact opening
velocity 1-10 m/s, the contact gap is between 1.57 to 6 mm. Thus, the arc motion for
a contact gap less than 1 cm can be explained in terms of magnetic field

Ref: Arc Control in Circuit Breakers: Low Contact Velocity

Slow Contact Opening Circuit Breakers

Piezoelectrics in Circuit Breakers: Design and Test

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers: Energy in High and Low speed

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers: Energy in High and Low speed: Energy in High and Low speed There are 20 chemical elements when the contact opening velocity 10 m/s and 19 chemical elements when the con...

Energy in High and Low speed

Energy in High and Low speed

There are 20 chemical elements when the contact opening velocity 10 m/s and 19
chemical elements when the contact opening velocity 1 m/s. The electron energy for
each chemical elements decrease as the wavelength increases. The maximum energy
when contact opening velocity at 10 m/s, is about 0.79x10-37 J higher than that
contact opening velocity 1 m/s. Both have the same minimum energy at 2.42x10-37 J
of the chemical element N I, O I and O II at the wavelength 821-824 nm. The average
energy when the contact opening velocity 10 m/s is higher than the contact opening
velocity 1m/s about 0.31x10-37 J.

Reference:

 

Arc Control in Circuit Breakers: Low Contact Velocity 

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers: Force in the Arc The total forces integrated alo...

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers:  Force in the Arc
The total forces integrated alo...:  Force in the Arc The total forces integrated along the arc length and contact opening velocities are shown in Figure 7.4. The results sh...

 Force in the Arc

The total forces integrated along the arc length and contact opening
velocities are shown in Figure 7.4. The results show no simple trend with contact
opening velocity. However, the data are compatible with an approximately constant
total force.
The results of the magnetic forces modeling here are lower than the modeling results
of Paul [11] who considered the magnetic driving force in the contact region from the
magnetic field from the conductors and steel plates in the side walls. The magnetic
flux density (B) was 31 mT/kA for the conductors in the air with a gap of 10 mm.
Thus, at an arc current 2000 A, the magnetic forces was about 1.24 N.
The arc chamber geometry is considered. The magnetic flux density calculation here
is considered at the point that the arc root moves from the contact region with contact
opening velocities.

 

Reference:Arc Control in Circuit Breakers: Low Contact Velocity

 

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers: Anode and Cathode root in Circuit Breakers

Dr. Kesorn Pechrach Weaver: Arc Control in Circuit Breakers: Anode and Cathode root in Circuit Breakers: Anode and Cathode root in Circuit Breakers The anode and cathode root displacement are shown in Figure 4.21. The results show that when...

Anode and Cathode root in Circuit Breakers

Anode and Cathode root in Circuit Breakers

The anode and cathode root displacement are shown in Figure 4.21. The results show
that when the pressure starts to rise up, both anode and cathode root still stay in the
contact region. At the period of 1800 μs, the second pressure rises up.
This is coincident with the point that the cathode root moves off from the fixed
contact. When the anode root moves from the contact region at the period of 2600 μs,
the pressure drops down shapely.
At contact opening velocity of 10 m/s (see Figure 4.16), the pressure rises earlier than
that of 1 m/s. The maximum pressure when the contact opening velocity of 1 m/s is
double that of 10 m/s. The arc root contact time at contact opening velocity of 1 m/s
is longer than that of 10 m/s. The period the arc root is in the arc chamber at contact
opening velocity of 1 m/s is shorter than that of 10 m/s.

Reference:

Arc Control in Circuit Breakers: Low Contact Velocity Paperback – 1 Jan 2017 by Dr Kesorn Pechrach PhD (Author)