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

Manufacturing, #draw a net sketch of the geometry of a single point tool.

#draw a net sketch of the geometry of a single point tool.

Evaluate maximum stress, Show that for a flat circular steel plate subjecte...

Show that for a flat circular steel plate subjected to uniform pressure on one surface, the maximum stress when the periphery is freely supported is 1.65 times that when the periph

Capacity planning, Capacity Planning: This unit defined different ways...

Capacity Planning: This unit defined different ways to measure capacity, set up maximum capacity, and calculate capacity utilization. The long-term and short-term strategies t

Evaluate tension in the string, A smooth sphere of radius 15 cm and weight ...

A smooth sphere of radius 15 cm and weight 2 N is supported in contact with a smooth vertical wall by a string whose length simlar the radius of sphere. The string joins a point on

Sizing a Motor that has a cable Pulley, I am stumped as to how to figure th...

I am stumped as to how to figure this out. It is a motor with a cable pulley to move the carriage in a wave tank. (the part that pulls the boat, etc). I have to build it on paper

Rope drive, Rope drive: What do you mean by the term rope drive? ...

Rope drive: What do you mean by the term rope drive? Sol: The ropes are circular in section. Rope-drive is mostly used when distance between the driving shaft and drive

Find out load lifted by the machine, Find out load lifted by the machine: ...

Find out load lifted by the machine: An effort of 400 N is applied in a lifting machine. The distance moved through effort is 4 m and that by load is 40 cm. If the efficiency

Gathering lines, Gathering Lines: A gathering line, also called a lad...

Gathering Lines: A gathering line, also called a ladder track, is one into which a number of parallel tracks merge. This is shown in Figure. It is used in marshalling yards.

Internal combustion engine - thermodynamics, Internal combustion engine - T...

Internal combustion engine - Thermodynamics: Internal combustion engine is popularly known as I.C. engine, is heat engine that converts the heat energy released by the combust

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