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About Mid Frequency DC Inverters

  
     
 
 
     
 
Medium Frequency
 
iPAK MFDC Inverters
Same components
Same programs

Medium frequency systems
Light transformers
High eficient power
Can reduce the cost of robots
Higher rate of head input
Shorter weld times
Three phase load distribuition
 
 
 
Disadvantages
 
• Small increase in cost control and transformer

• Necessary to amend the construction of the gun in order to
  reduce unnnecessary resistance.

• capacitors life is not infinite 		• Capacitors remain charged for up to 5 minutes after power off

• Good water flow is essential for life of the transformer and diode

• High voltage primary change in the behind the safety aspects of guns
 
 
Advantages
 
• Significant reduction in size and weight of the transformer.
  for example:

• Roman TDC 1051 – 100kVA MF transformer = 25kg.

• ISO compact – 100kVA AC transformer = 50kg.

• Standard Package - 100kVA AC transformer = 128kg.

• True three phase load distribuition.

• Power factor of transformer is very good.

• Roman TDC 1051 – power factor = 0.9 to 1.0.

• Standard Package – power factor = 0.1 to 0.8.

• Capacitive load maintained by the control system.

• Higher rate of head input provides shorter solder
  (aproximately 20%)

• Natural ramps at the beginning of the weld.

• Exccellent welding, even with coated materials.

 High current capacity in the secondary

• In AC systems the secondary current is ultimately limited by impedance of the secondary circuit. If a 15 Volt secondary system has 0.7 power factor,reactance and resistance of 1 miliohm, the impedance will be 1,41 miliohms. If the secondary current will limited to10,714 Amps.

• In a system of medium frequency secondary current is limited ultimately only by the resistance of the secondary circuit, provided with the DC component of the reactance is zero. Therefore, with the same conditions above the effective impedance will be only 1 miliohm and secondary current will be limited to a value much higher than 15,000 Amps		   High speed response constant current

•In AC systems with constant current response timer is a best 8.33 miliseconds,and the measurement obtained in the corresponding half cycle. However correction is made in the next cycle.(this lag results in change to greater or smaller angle shooting and is stable only at the edge of the stage,sometimes contribuiting to higher peak surges).

• In our mid-range system, feedback from current and all controll occurs within each half cycle of 500 microseconds (there is not gap between measurement and control provides more accurate value of current with virtualy no change in phase angle and close to the ideal stabily

 Current peak smaller reduction of weldr splash extending the life of the electrode

• 22kA is the approximate value of peak current for a typical applicatiion of supply with AC 10KA and heat around 50% approximately.

• 10 KA is the approximate value of peak current for a typical application with a drive current constant and independent of the heat.

• Peak currents result in lower current density smaller thereby reducing the possibiliy of weld expulsion.

Short:
• Lower energy costs
• Lower cost of infrastructure
• Lower cost of inputs

 
 
 
Comparison of costs
 
Several factors combine to provide greater energy savingswhen used for medium frequency inverters:

• Due to the inductive reactance of the transformer, the maximum current is greater. So we can have more current to the same voltage or the same current to a lower voltage.

• Since the transformer primary is directed to a power source three-phase rectifier, the primary supply of 1kHz for the processor is not greater.		   • Both of these factors allows us to use a transformer with more turns being the primary current is much smaller compared to a conventional AC system.

Example :
Using AC with 15v and the secondary current 10,000 Amps current primary 480v=line current=312 Amps.Using MF with 10v and the secondary current 10,000 Amps current primary than 480v instead of 680V or so. 680v=147 Amps=line current=84.9 A.
 
 
Comparison of inverters
 

Inverter 600 amps common (standard US)
 BFE MF-Pak 600 (25% more powerful)
 

Inverter 2000 amps common ( standard US)
 BFE MF-Pak 1500 (More powerful than those of 2000 Amps)
 
 
Range of inverters BFE
 

TRUE HIGH-RATINGS
 
 
iPAK – Integrated inverter systemr
 

WS2000M3 + MF-Pak + 400 years = iPAK
 
 
Inverter system iPAK 1
 
Features:

• Integrated into the weld processor
• Integrated Inverters 1000Hz.
• Optional Ethernet.
• Optional Fieldbus .
• Real-time constant current control.
• Control of the steering angle.
• Pressure Control .
• I/O Expansion optional.
• Compact design.
• Dynamic monitoring.
• Millisecond Timing
• Excellent cost-benefit.
 
 
Inverter system iPAK 2
 

Choice of Air cooled or Water cooled up to 600A.
Water cooled only on units larger than 1000 Amp.
Modular construction.