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DC Filtering Capacitor for Medium-Frequency Coreless Induction Furnace - China Suppliers & Factory
DC-link induction heating capacitor for metallurgical manufacture
- 1Oil-immersed water cooling capacitor and Dry-type metalized film capacitor and for options.
- 2Max rated voltage: 3500VDC
- 3Max capacitance: 10000uf
- 4Mainly applied for AC current 3-phase 380VAC, 575VAC, 660VAC（internal series power supply），Series resonant induction heating system which frequency lower than 10Khz
Function of DC power induction heating capacitor
- 1DC-link support;
- 2Filtering low and high frequency ripple wave;
- 3Bypass series resonance current;
Feature of dry-type film capacitor for mid-frequency furnace
The dc filtering film capacitor developed for mid-frequency furnace, which employed natural cooling, no need cooling water placed in. The design will save cost on cooling system and maintenance. But the working frequency and over-current can’t be as high as water cooled type capacitor.
While ironmaking and steel making process by medium-frequency coreless induction melting furnace, voltage sags and swells will be in good control.
What is good to use a coreless induction melting furnace?
- 1line currents on the supply side are nearly balanced
- 2flicker contribution is below the limits specified in the standards;
- 3reactive power demand is relatively low and the variations in the magnitude and rate of change of active power are not drastic
- 4no voltage sag and swell phenomena arising from furnace operation.
Power circuit diagram of a typical medium-frequency coreless induction melting furnace
The below picture is dry type capacitor designed for coreless mid-frequency induction melting furnace
General introduction
- 1Metal shell encapsulation, dry epoxy resin potting ;
- 2Pure copper electrodes, vertical/horizontal installation;
- 3Compacted design;
- 4self-healing metalized dielectric;
- 5High voltage, High ripple current, high dv/dt withstand capability.
General spec
| Capacitance range |
100μF～20000μF |
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| Rated voltage Un |
600VDC～8000VDC |
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| Capacitance.tolerance |
±5%(J) ;±10%(K) |
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| Withstand voltage |
Vt-t |
1.5Un DC/60S |
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Vt-c |
1000+2×Un/√2 （V.AC） 60S(min 3000 V.AC) |
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| Over-Voltage |
1.1Un(30% of on-load-durability.) |
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1.15Un(30min/day) |
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1.2Un(5min/day) |
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1.3Un(1min/day) |
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1.5Un(100ms every time,1000times during the lifetime) |
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| Dissipation factor |
tgδ≤0.003 f=100Hz |
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dielectric loss tgδ0≤0.0002 |
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| Insulation resistance |
Builtin-discharge resistor |
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| Withstand pulse current |
contact for details |
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| Effective current/Irms |
contact for details |
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| Stray induction/ ESL |
＜150 nH |
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| Flame retardation |
UL94V-0 |
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| Maximum altitude |
2000m |
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The altitude reach above 2000m, the capacitor must be used at derated capacitance and current value, 10% decreased at every increased 1000m |
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| Life expectancy |
100000h(Un; Θhot spot ≤70 °C ) |
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| Reference standard |
IEC 61071 ;IEC 61881; |
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| Operating temperature |
-40℃~+ 70℃ |
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Expected lifespan chart
Frequently Asked Questions (FAQ)
Q: What types of DC-link induction heating capacitors are available?
A: You can choose between Oil-immersed water cooling capacitors and Dry-type metalized film capacitors depending on your system requirements.
Q: What is the maximum rated voltage and capacitance of these capacitors?
A: The maximum rated voltage reaches up to 3500VDC, and the maximum capacitance is 10000uf.
Q: What are the primary functions of the DC power induction heating capacitor?
A: The primary functions include providing DC-link support, filtering low and high frequency ripple waves, and bypassing series resonance current.
Q: What are the design features of the dry-type film capacitor for mid-frequency furnaces?
A: It features metal shell encapsulation, dry epoxy resin potting, pure copper electrodes, self-healing metalized dielectric, and natural cooling. This design eliminates the need for cooling water, saving costs on the cooling system and maintenance.
Q: What are the benefits of using a coreless induction melting furnace?
A: Benefits include nearly balanced line currents on the supply side, low flicker contribution within standard limits, relatively low reactive power demand with stable active power, and no voltage sags or swells arising from furnace operation.
Q: What is the expected lifespan of the DC-link capacitor?
A: The expected lifespan is 100,000 hours under rated voltage (Un) and at a hot spot temperature of ≤70 °C, in accordance with IEC 61071 and IEC 61881 standards.