Equipment for resistance welding-single phase vs three phase, Mechanical Engineering

EQUIPMENT FOR RESISTANCE WELDING-Single phase vs three phase

The resistance welding machines can be connected either across 440 V mains (across two lines) or three phase mains. Among the three phase machines, frequency converter and rectifier systems are the two main categories. Fig. gives the line diagrams of single phase and three phase machines.

790_euip for resist weld.jpg

Single phase machines are simpler, less costly and cheaper than three phase equipments. Maintenance and installation are easier with single phase machines. The single phase machines having the same capacity as the three phase machines, possess the same performance capabilities. The power factor is lower (40 to 50 %) in the former case, but a high kVA demand is required for a brief period. Unless the loads are properly recalculated and properly redistributed and designed, heavy flickers (cyclic and non - cyclic voltage reductions) will results. Though, the total load is not much, fixed charges are high (because of trend by service, power factor, connected load). Because of the decreased frequency in the secondary, the power factor in the case of three phase machines is 85 % or more. They are not generally suitable for welding of thin metal or weld times of three cycles or less is required. Three phase transformers generally have not been applied to multiple electrode or multiple transformer machines since balancing is otherwise possible in those cases.

 

Posted Date: 9/17/2012 4:25:40 AM | Location : United States







Related Discussions:- Equipment for resistance welding-single phase vs three phase, Assignment Help, Ask Question on Equipment for resistance welding-single phase vs three phase, Get Answer, Expert's Help, Equipment for resistance welding-single phase vs three phase Discussions

Write discussion on Equipment for resistance welding-single phase vs three phase
Your posts are moderated
Related Questions
Advantages of resistance welding   1. Resistance welding is very fast compared to arc welding. 2. Almost any combination of metals can be resistance welded provided necessa

Technical Limitations of Extension of screw conveyor Technical Limitations: Breakdown of hinged joint at intermediate condition of link. ?Not proper extension of coaxi

Clearance Volume ( V C ) : The nominal volume of the combustion chamber above the piston when it is at the top dead centre is the clearance volume. It is designated as V C an

Q.   Derive the expression of torque developed in closely excited magnetic system. Clearly explain then assumption made.   Sol. Double - Excited System   A doubly - ex

Use the graphics and the equation to define the term principal stress and principal planes.


what are the Standard grades of pure iron used for magnetic applications?

Throttle Free Play Adjustmen: A smooth operation of the throttle ensures proper acceleration of the vehicle according to the requirement of the rider. If the throttle cable is kin

(a) What do you mean by machinibility ? Discuss the factors which come into play while evaluating the machinability of any metal. Also describe machinability index. (b) Brass co

Case study entitled " Exxon Valdez Oil Spill Disaster ". 1.      Examine the aim and objectives of Exxon Mobil Corporation. 2.      Carefully observe the oil and refinery ind