Duty cycle rating, Mechanical Engineering

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.

 

 

Posted Date: 9/14/2012 4:22:26 AM | Location : United States







Related Discussions:- Duty cycle rating, Assignment Help, Ask Question on Duty cycle rating, Get Answer, Expert's Help, Duty cycle rating Discussions

Write discussion on Duty cycle rating
Your posts are moderated
Related Questions

steady state amplitude

This is to determine the best possible angle to reduce aerodynamic drag. Mesh is to use tetrahedron of 0.5m wide.  I need the mesh generation and solver control on ansys 11.0. I al


ismb 600 load capacity length in 8 meter

A Perspex tank ure 1), which has parallel sides for the top part of its height and a 'V' shaped section for the bottom part and a constant width throughout, is used as a receptacle

Half-space Method Solid representation is based fundamentally on the notion that a physical object divides an n-dimensional space E n into two regions: interior and exterior,

Implementation of Material Requirement Planning: The total requirements for a material from an MRP schedule are given in the following table :

Slip-On Flanges Slip-on flanges are limited to use under the following conditions: ASME/ANSI B16.5 standard forged flanges for design pressures and coincident temperatures n

Q. can you explain Shell molds? These molds are prepared by pouring a mixture of sand and thermosetting resin over the heated surface of a metallic pattern, which results into