1.1 Before using KS-AAE active arc extinguisher, please be sure to carefully and thoroughly understand the characteristics and use restrictions of KS-AAE active arc extinguisher to avoid possible accidents caused by improper use.
1.2 The KS-AAE active arc extinguisher is an arc-extinguishing product applied in the breaking process of DC mechanical switches. The effect of arcing on mechanical switches is reduced step by step by controlling the intensity and time of arcing (μs magnitude). For non-customized KS-AAE active arc extinguisher, its purpose is not to completely prevent mechanical switches in the breaking process from arcing.
1.3 The KS-AAE active arc extinguisher does not have arc extinguishing capability for mechanical switches in AC occasions. If it’s required to solve the problem of AC arc extinguishing for mechanical switches, please pay attention to KS-AST series AC no-arc device of Kingser.
1.4 The KS-AAE active arc extinguisher does not have arc extinguishing capability for closing and bouncing of mechanical switches. If it’s required to solve the problem of closing and bouncing of mechanical switches, please pay attention to other products of Kingser.
1.5 The KS-AAE active arc extinguisher are equipped with various models and the appropriate model should be selected according to the characteristics of mechanical switch and application occasions.
Four parameters should be considered when selecting KS-AAE active arc extinguisher: rated voltage, rated current, control type and control arcing time (or starting voltage). The rated voltage, rated current and control type shall be determined according to the occasion where the mechanical switch is used; and the control arcing time (or starting control voltage) shall be determined according to the occasion where the mechanical switch is used and its characteristics. It is strictly prohibited to use KS-AAE active arc extinguisher in occasions beyond the specification range.
If you have any questions about the model selection, please contact the technical personnel of Kingser.
2. The Principle of KS-AAE Active Arc Extinguisher
Fig. 1(a). Schematic diagram of KS-AAE
Fig. 1(b) The arcing diagram without KS-AAE device
Fig. 1(c) The arcing diagram with KS-AAE device
During the breaking process of the mechanical switch, the electric field between the contacts of the mechanical switch will ionize the medium between the contacts and cause arcing. The arcing generates intense heat in a short period of time and damages the contacts, causing the contact resistance of the mechanical switch to increase or even adhere, and also damaging the insulation characteristics of the mechanical switch. As shown in Fig. 1(a), the KS-AAE active arc extinguisher are connected in parallel at both ends of the load，when the mechanical switch is closed, KS-AAE active arc extinguisher stores energy. When the mechanical switch is breaking, KS-AAE active arc extinguisher releases the stored energy at an appropriate time after detecting the arcing to block the electric field at both ends of the mechanical switch and extinguish the arcing, as shown in Fig. 1(c).
3. The Mechanical Switch Characteristics and Arc Extinguishing Capability of KS-AAE Active Arc Extinguisher
When the breaking voltage and current are not changed, the breaking speed, arcing characteristics and target mechanical life of the mechanical switch affect the selection of relevant parameters such as arcing time (or starting voltage) and the like of KS-AAE active arc extinguisher.
a) Control arcing time type
Fig. 2 The relationship between the distance between contacts and reignition after arc extinction.
The KS-AAE active arc extinguisher with control arcing time releases stored energy when the arcing time reaches the control time so as to reduce the electric field strength between the contacts to around 0. After the stored energy is released, the electric field between the contacts will be reestablished. As shown in the figure, the control time is Tct. When the electric field is reestablished, the voltage between the contacts is Vct and the contact spacing is Dct. The breakdown voltage between the contacts at this time is Vbk. The smaller the Tct, the smaller the Dct and the corresponding Vbr. When Vbk is smaller than Vct, the reestablished electric field will ionize the medium between the contacts again, causing the arc to reignite. Therefore, the selected arcing control time must ensure that KS-AAE active arc extinguisher has sufficient gap (insulation strength) between contacts after releasing stored energy to avoid re-breakdown of medium by reestablished electric field. We should:
1) Know about the breaking speed of the mechanical switch and the arcing characteristics of the occasion, and the selected arcing control time shall ensure that the mechanical switch moves to a safe minimum distance.
2) Know about the rebound characteristics of the mechanical switch to avoid the mechanical switch rebounding to a safe minimum distance after arc extinguished.
3) Know about the effect of voltage, current, temperature and humidity, electromagnetic environment and medium characteristics of mechanical switches on the minimum safe distance.
4) When the voltage on the load suddenly changes while the mechanical switch is kept closed, the appropriate KS-AAE active arc extinguisher should be evaluated and used according to practical situation.
5) The customized KS-AAE active arc extinguisher increases the time of energy release to prolong the maintenance time of zero electric field between contacts.
The control arcing time type KS-AAE active arc extinguisher identifies that the mechanical switch is breaking and arcing by capturing the voltage mutation at both ends of the load. When there is a resistance-capacitance or capacitance absorption loop between the contacts of the mechanical switch, the voltage waveform of the mechanical switch loses mutation at the moment when the mechanical switch breaks, which will affect the correct identification of the breaking and arcing by KS-AAE and cause arcing to fail to start.
Fig. 3 The effect on KS-AAE active arc extinguisher when resistor-capacitor arc extinguishing between mechanical switches.
b) Starting voltage type
The starting voltage type KS-AAE active arc extinguisher releases stored energy when identifying that the load voltage decreases to a specified voltage value. The smaller the starting voltage is, the shorter the arcing time is. However, even if different mechanical switches are breaking under the same voltage and current conditions, the arc pressure difference across the mechanical switches is obviously different. The KS-AAE active arc extinguisher performs parameter calibration under test conditions according to common mechanical switches, and the calibrated parameters do not completely cover the characteristics of all mechanical switches. If you don't know the switch characteristics and application occasions, blindly reducing the starting voltage will also have the possibility of arc reignition. It is recommended to select appropriate parameters according to the actual application conditions before use.
Before using the KS-AAE active arc extinguisher with start-up voltage, the ripple characteristics of DC power supply voltage must be understood. When the ripple is larger than the starting voltage, KS-AAE active arc extinguisher will malfunction and affect arc extinguishing. If the ripple frequency is too large, KS-AAE active arc extinguisher may be damaged.
When starting voltage KS-AAE active arc extinguisher is used, it must be:
1) Know about the application situation and breaking arcing characteristics of mechanical switches, select appropriate starting voltage value, and make evaluation according to actual application when necessary;
2）When the ripple voltage of the power supply is greater than the start-up voltage, it is not recommended to use the start-up voltage KS-AAE active arc-extinguisher, but to use the control arcing time type.
3）Customizing enhanced KS-AAE active arc extinguisher when adjusting starting voltage is not convenient.
Fig. 4 The relationship between starting voltage and arc extinguishing reliability of KS-AAE active arc extinguisher
4. The Breaking Voltage and Current and Arc Extinguishing Capability of KS-AAE Active Arc Extinguisher
The same mechanical switch has different arcing characteristics under different voltage and current levels. Correspondingly, KS-AAE active arc extinguisher have different arc extinguishing protection capabilities for mechanical switches under different voltage and current. Using KS-AAE active arc extinguisher beyond the rated voltage and current has the risk of arc extinguishing failure. The KS-AAE active arc extinguisher can't exert the maximum protection efficiency by excessively reducing the specification.
Fig. 5 is a breaking arcing curve of the same mechanical switch at different current levels. The starting voltage type KS-AAE active arc extinguisher with rated current meeting I3 is selected, and the starting voltage is much lower than the arcing voltage at I1. If it is used under I1 condition, KS-AAE active arc extinguisher releases energy at the moment when the mechanical switch is turned off. At this time, it is possible that KS-AAE active arc extinguisher has poor arc extinguishing effect due to too small an opening distance of the mechanical switch. If the KS-AAE active arc extinguisher with rated current meeting I3 is used under the I1 condition and a longer control arc extinguishing time parameter is selected, the arc may be at the tail end of self-extinguishing when the KS-AAE active arc extinguisher releases energy, and the nominal arc extinguishing effect is also not achieved.
The KS-AAE active arc extinguisher has the best arc extinguishing capability only for the working voltage within a certain interval, as shown in Fig. 6. NOT all working voltages below the rated voltage range have the same arc extinguishing effect. Please refer to the specifications of the specific models of KS-AAE active arc extinguisher for the minimum effective arc extinguishing voltage.
The rated current of KS-AAE active arc extinguisher is a relative value, not an absolute value, which only represents the current value of effective arc extinguishing with respect to the rated voltage. For situations where the working voltage is lower than the rated voltage, the current value that can effectively extinguish arc may be lower than the rated current value.
Fig. 5 Arcing curves of mechanical switches at different current levels
Fig.6 Operating voltage interval for effective arc extinguishing
5. The Load Characteristics and Arc Extinguishing Capability of KS-AAE Active Arc Extinguisher
The KS-AAE active arc extinguisher calibrates parameters based on resistive load. Under the application of non-resistive load, the arc extinguishing efficiency of KS-AAE active arc extinguisher will be reduced, and it may even be damaged due to improper use. For application under non-resistive load, please contact the technical personnel of Kingser.
6. The Effect of KS-AAE Active Arc Extinguisher on Load
Some models of KS-AAE active arc extinguisher will apply an overvoltage pulse to the load when extinguishing arc and releasing energy. Please refer to the specification for the pulse size and width. When using, please evaluate the effect of overvoltage output by KS-AAE active arc extinguisher on load.
7. The Connection Distribution Parameters and Arc Extinguishing Capability of KS-AAE Active Arc Extinguisher
The connection impedance and distributed inductance in electrical connection will affect the arc extinguishing effect of KS-AAE active arc extinguisher. The impedance and distributed inductance of the red wire in Fig. 7(a) shall be reduced as much as possible during connection of KS-AAE active arc extinguisher. It is suggested that:
1）Connect wires meeting current requirements.
2）Wiring between power supply and mechanical switch, KS-AAE active arc extinguisher and mechanical switch, KS-AAE active arc extinguisher and power supply shall be shortened as much as possible. As shown in Figure 7(b), DC power supply, mechanical switch and KS-AAE active arc extinguisher shall be installed nearby.
3）Each connecting line adopts a straight short line, and it is forbidden for the line body to surround or bend into a ring shape..
4) The connection between wires shall be tightly crimped and the contact impedance shall be reduced as much as possible.
Fig. 7 The Effect of KS-AAE Active Arc Extinguisher on Connection Impedance and Distributed Inductance.
8. Limitations on Continuous Operation Time Interval of KS-AAE Active Arc Extinguisher
The energy required for KS-AAE active arc extinguisher to extinguish arc comes from the energy stored during the closing of mechanical switch. If the mechanical switch is kept closed for too short a time, the energy storage of KS-AAE active arc extinguisher is insufficient, and its arc extinguishing capability cannot be guaranteed, as shown in Fig. 8.
When in use, it must be ensured that the time for the mechanical switch to remain closed is longer than the energy storage time of KS-AAE active arc extinguisher.
Fig. 8 Continuous action time interval of KS-AAE active arc extinguisher
9. The Effect of Temperature on KS-AAE Active Arc Extinguisher
Working in a high temperature area beyond the operating temperature range will accelerate the aging speed of KS-AAE active arc extinguisher. Working in a low temperature area beyond the working range will reduce the arc extinguishing capability of some models of KS-AAE active arc extinguisher. KS-AAE active arc extinguisher must be used in the environment within the specification range.