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Solution
Electroplating

New generation current transformer specially for welding machine——rogowski coil

     Rogowski coil also called current measurement coil, the differential current sensor, is a toroidal coil that wrapped uniformly in nonferromugnetic material. Its output signal is differential of current to time. Through an integral circuit on the output voltage signal, it can restore input current truly. Compare with traditional iron-core transformers, rogowski coil has the following characteristics: current can be measured real-time, response speed is fast, not saturated, almost no phase error. So it can be applied in signal distortion situation of relaying, thyrode, frequency control, resistance welding. Rogowski coil is the ideal succedaneum of traditional inductive transformers and hall transformers.
Typical characteristic
● Light in weight                   ● Strong ability of overcurrent  
● Good linearity                   ● No risk of secondary circuit
● Wide bandwidth                ● Jamproof to electromagnetic   
● Apply to milliampere to megampere measurement
Applications
● Power harmonics detection                    
● Rectifier current measurement
● Welding machine current measurement          
● Insulator leakage current measurement
● Mesohigh switch cabinet protection system     
● Calcium carbide furnace, furnace transformer
● Capacity discharge, lightning current detection  
● Electric motor overload/short circuit protection
● Measure leakage current and breaking current of circuit breaker
● Motor servo system, power system, railway signaling and haulage motor
● Measure induced current in the conductor around large electrical equipment
● Large complex conductor earth fault detection secondary side current detection
● Gathering of inverter and various frequency current like solar energy, wind energy
 
     There are a lot of difficulties in electric welding machine current measurement and control. It is pulse signal, and pulse width spans a large range(from a few milliseconds to several seconds), and general isolate current measurement can’t meet requirements. Now, integrate Pinyan’s own technological superiority, we put forward the following program.
Solution 1 Overview
     Rogowski coil and integrator are adopted in this solution. With the characteristics of wide bandwidth, no saturation, good isolation and so on, Rogowski coil is suitable for similar current measurement in special occasions. The integrator will be customized according to the case and the mainboard of electric welding will control it. That is the mainboard of party B should be:
1. Power supply:5-9V DC;
2. Switch signal:5V;
      In this solution, it provides a group of voltage signal (representing the measured current waveform) for the following mainboard processing. 
Action description
      The case: The ainboard controls the current output of electric welding and its control circuit decides the breaking action. A reset signal is needed from party B. That is the signal is sent to integrator for reset before turn on and after turn off the current. It is shown as below:

The output signal of integral goes into the mainboard directly for following processing.

Solution 2 Overview
    The originally created carrier wave following technology of Shanghai PINYAN M&C Technology Co., Ltd. is adopted in this solution. The welding current can be measured precisely without the integrator cooperated with timing. For more details, pls contact us.

Single pulse waveform of detection 

Staircase waveform 

Comparison with the German HWH system 

Application of flexible Rogowski coil in welding machine 


Conclusion
    The integrator in our solution is specially designed. With regular integrator, pulse current in seconds can’t be restored. After all, Rogowski coil is mainly suitable for AC occasions, while pulse current in seconds basically belongs to DC. Our products have many successful cases and can be replacement of foreign brands. Pls contact us if you have anything unclear.

                                           Shanghai PINYAN M&C Technology Co., Ltd.     Add: Unit 55, No.2155, Lianhua south Road, Minhang District, Shanghai, China(201109)
                                                                          Tel: +86 021 64850006    Fax: +86 021 64850006    E-mail: [email protected]