High-power medium-frequency supplies cover the 5 ton to 40 ton class, in catalog bands up to about 20,000 kW. A 12-pulse or 24-pulse rectifier is used so a large furnace can be connected without disturbing the plant grid.
Technical Data
| Input voltage (V) | Rectifier | Medium-frequency output (V) | Furnace body voltage (V) | Output power (kW) | Furnace capacity (t) | Output frequency (Hz) |
|---|---|---|---|---|---|---|
| 380 | 6 or 12 pulse | 750 | 750/1500 | 20–1000 | 0.01–3 | 150–1000 |
| 660 | 6 or 12 pulse | 1200 | 2400 | 500–3000 | 1–8 | 500–1000 |
| 660 | 6 or 12 pulse | — | — | 2000–4000 | 2–10 | 500–1000 |
| 1000 | 12 or 24 pulse | 1600 | 3200 | 4000–8000 | 5–12 | 250–500 |
| 1000 | 24 pulse | — | — | 8000–20000 | 12–40 | 150–250 |
| Item | Catalog statement |
|---|---|
| Start | Automatic frequency-sweep start |
| Rectifier control | Large-scale phase-shift trigger, strong anti-interference |
| Current limit | Holds under load change so a bridge does not trip the supply |
| Protection | Short circuit, open circuit, phase loss, low water, water shortage, over-current, over-voltage, phase stagger |
| Fault stop | Automatic safe stop |
| Rectifier pulse | 12 pulse and 24 pulse to cut grid harmonics |
| Melt under 1 t | One furnace in 20 to 50 minutes |
| Power saving stated on the sheet | 10–20% against a traditional medium-frequency furnace |
| Rectifier | 5th | 7th | 11th | 13th | 17th | 19th | 23rd | 25th |
|---|---|---|---|---|---|---|---|---|
| 6 pulse | 0.175 | 0.11 | 0.045 | 0.029 | 0.015 | 0.01 | 0.009 | 0.008 |
| 12 pulse | — | — | 0.007 | 0.004 | 0.002 | 0.001 | 0.0009 | 0.0008 |
| 24 pulse | — | — | — | — | — | — | 0.0006 | 0.0005 |
| US standard | Applies to |
|---|---|
| IEEE 519 | Harmonic current limits, matched to 6 / 12 / 24 pulse rectifiers |
| NFPA 70 (NEC) | Incoming voltage, grounding and disconnect |
| UL 508A | Control cabinet construction |
| NEMA 250 | Enclosure type for the power cabinets |
| NEMA MG 1 | Cooling-fan and pump motors |
Every figure in these tables is taken from the factory sheets in the product folder and is written in English. 1 metric ton = 1.102 US short tons. Power-supply ratings can still be negotiated to the customer requirement, as the sheet itself states. American standards are the US specifications normally requested with this equipment.
Key features
- 12-pulse and 24-pulse rectifiers
- Catalog band about 4,000–20,000 kW
- Furnace voltage and frequency matched to 8 t, 10 t, 12 t, 15 t, 20 t, 30 t and 40 t bodies
- Built as part of the complete large-capacity melting system
Construction
- Multi-cabinet line-up: rectifier cabinets, inverter cabinets, capacitor room and cooling connections.
Working principle
Higher pulse counts cancel more harmonics on the incoming line. The inverter still follows the furnace frequency as the heat progresses.
Applications
Steel, cast iron, stainless steel, copper, aluminum, aluminum alloy, brass and other non-ferrous metals.
Complete system integration
This equipment sits in the same line as the power supply, the capacitor bank, the induction coil, the magnetic yoke, the furnace body and the cooling system. A quotation can cover one item or the full line.
Customization
Capacity, voltage, frequency, dimensions and connection layout can be made to the furnace design. Send the drawing or the duty data below.
Catalog sheets
Questions before a quotation
Can the rating be customized?
Yes. Capacity, voltage, frequency, tube size and connection layout follow the furnace drawing and the metal.
What do you need for a quotation?
Furnace capacity, metal, melting temperature, melting rate, working hours, input voltage, frequency if known, tilting method and cooling-water conditions. A drawing helps.
Do you supply a single machine or the complete system?
Both. A spare coil, yoke, capacitor or cooling tower can be quoted alone. A new foundry line is quoted as a complete system.
Which metals can be melted?
Steel, cast iron, stainless steel, copper, aluminum, aluminum alloy, brass and other non-ferrous metals. The lining and the frequency follow the alloy.
Will you confirm the catalog numbers before manufacture?
Yes. The sheets on this page are the factory catalog for selection. The quotation states the rating that will be built.