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

Assignment Help:

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.

 


Related Discussions:- Equipment for resistance welding-single phase vs three phase

Define the nature of force in a member of truss, Define the nature of force...

Define the nature of force in a member of truss: How can you define the nature of force in a member of truss? Sol.: We know that whenever force is applied on a cross se

Describe the type of facing and backing sand, Q. Describe the type of Facin...

Q. Describe the type of Facing and Backing sand? Facing sand. This sand is used directly next to the surface of the pattern and comes into contact with the molten metal when th

Compression ratio and mean effective pressure, Compressio n Ratio: It...

Compressio n Ratio: It is calculated as shown below Mea n Effective Pressure (P m   o r P me f ): Mean effective pressure is the hypothetical consta

Find out the forces in members, Find out the forces in members: A brac...

Find out the forces in members: A braced support ABC is loaded as illustrated. Find out the forces in members AB, BC, BD and AD by the method of joints. Check out the results

Obtain the closed loop transfer function, Question: The block diagram o...

Question: The block diagram of a dc servo motor feed drive is shown   Obtain the closed loop transfer function relating the output to the disturbance T L while V

Calculate the pressure using density , An open test tube at 293 K is filled...

An open test tube at 293 K is filled at the bottom with 24.2 cm of Hg, and 11.2 cm of water is placed above the Hg. Calculate the pressure at the bottom of the test tube if the atm

Elements of cad, Human Factor : The human factor is the key factor in th...

Human Factor : The human factor is the key factor in the success of CAD system. This concerns the training of the designer or the engineer without whom the CAD system become

Capp, explain capacity planning system

explain capacity planning system

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd