Duty cycle rating, Mechanical Engineering

Assignment Help:

DUTY CYCLE RATING


Since, arc welding power sources are delivering high currents for welding; the components of such a system are bound to get heated. In order to have increased life of such components the heating should be limited. This is done by specifying what is called as "Duty Cycle". The duty cycle is explained as a percentage and at a particular current level.

Example: 60 % duty cycle at 400 A This specification says that 400 A welding current can be used continuously upto 60 % of a base period. The base period for duty cycle calculations in many of the standards is five minutes.60 % of five minutes is three minutes. Which means 400 A welding can be done without break for three minutes and for two minutes the power source should be allowed to cool down. Fig. shows the duty cycle rating.

989_duty cycle 1.jpg


If the same power source is used to deliver 500 A welding current then to avoid over heating of power source components the duty cycle has to be reduced.

759_duty cycle 2.jpg

Since the heating is proportional (I2R) the duty cycle rate for different currents are related by this simple formula.

                   I21T1=I22T2

If we now want to calculate the duty cycle for 500 A then,


                    = (400 / 500)2 X 0.6
                    = (4 / 5) 2 x 0.6
                    = (16 / 25) x 0.6
                    = 38.4 %


which means 500 A current can be used for 1.9 minutes without break and the power source should be allowed to cool for 3.1 minutes before next welding. For automatic welding applications the power source should be rated for 100 %  duty cycle (continuous current) at the desired welding current.

 

 


Related Discussions:- Duty cycle rating

Manual engineering drawing , Manual Engineering Drawing: The physical o...

Manual Engineering Drawing: The physical object is to be drawn (Do not take photographs of the object or use it as a template that you trace with) in class as an isometric dra

Motorcycle pulls to one side motorcycle problem, If Motorcycle Pulls to One...

If Motorcycle Pulls to One Side Causes of Problem Remedy Misaligned shock Absorber Front and rear wheels are not alig

What do you mean by rigid bed models, Q. What do you mean by Rigid bed mode...

Q. What do you mean by Rigid bed models? Models with rigid boundary and geometrically similar form are used in studies connected with outlet works, stilling basins, spillways

Explain the height adjustment and extension of augers, Normal 0 ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Simple single machine system, Consider a simple single machine system. It c...

Consider a simple single machine system. It consists of workpieces that enter the system, wait their turn to be processed on a single machine, and then depart the system. The workp

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