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
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 |
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)
The DC-link induction heating capacitor features a maximum rated voltage of 3500VDC and a maximum capacitance of 10000μF, with custom options ranging up to 20000μF and 8000VDC.
Its primary functions include providing robust DC-link support, filtering low and high-frequency ripple waves, and bypassing series resonance current.
It utilizes a metal shell encapsulation, dry epoxy resin potting, pure copper electrodes (for vertical or horizontal installation), a compacted design, and a self-healing metalized dielectric that withstands high voltage, high ripple current, and high dv/dt.
Dry-type capacitors employ natural cooling, eliminating the need for cooling water. This design saves on cooling system costs and maintenance. However, its working frequency and over-current limits are generally lower than those of water-cooled capacitors.
A coreless induction melting furnace ensures nearly balanced line currents on the supply side, keeps flicker contribution below standard limits, maintains relatively low reactive power demand without drastic changes in active power, and eliminates voltage sags and swells arising from furnace operation.
These capacitors have an operating temperature range of -40℃ to +70℃ and a life expectancy of 100,000 hours under rated voltage (Un) when the hot spot temperature remains ≤70°C.