Core lamination testing of induction motors 

230V secondary doesn't have any winding or wiring

Normally shop supply that 230V is applied in ring flux test

Purpose of ring flux test is to know whether core short or not. Normally core should not be short

Core repair process is known as core re stacking or re staggering

If u keep secondary open less current will flow(safe for testing)if short more current. If u want u can loop cable in every slot. My secondary cable was small.

@@practicalelectrical9416 Sir i have tried this with 5.5kw motor stator core with 2.5sqmm cu cable with supply 220v ac & the result is that, at the time of mcb on got tripped. Please can u guide us...???

@@ashutoshyadav6000 what was ur secondary voltage ? what u had used to vary supply voltage ?

Ya

primary side give ac supply mostly above 110v to 200v

core is laminated iron sheets. they get damaged ig winding burns in slots , corrosion and aging .

Try it practically.

U can go for core restacking.

U can do core restacking, issue can be solved.

did't understand ur question .

There is not High or low voltage differentiation in core test, all types of machine core tested at low voltage only

इंग्लिश लैंग्वेज सभी को समझ में आती है समझ गए दर्शन जी

In this test voltage is not important as we check heat Disepation. So applied current in kept under control n core heat is noted. Secondly we can replace the core or we can try core restacking.

@@practicalelectrical9416 so we should use a current transformer or what? Is it feasible to re stalk a LV motor? On that particular motor what you did for correction, is there any particular range of temperature rise so that to ignore a hotspot in the core.

@@harishharikumar1543 u can use any transfomer whoes voltage can be varied n secondly we used core staking for this motor.

Here current flow will create heat. So u have to increase voltage till u get enough current. For that u must use variable voltage regulator.

In short it's called open circuit test which is done in transformers. Generally we keep secondary open, shorting secondary will consumer huge current n high temperature. So keeping secondary open is on safer side.

In this test we look for abnormal temperature rise. So basically we are inducing emf to generate heat. There is no formula for it, u just have to generate heat which is controllable.

@@practicalelectrical9416 but how can I conclude that stator packet in ok or not..I don't have any parameter to compare.. for eg i got temp 35 deg c in one place and 45 deg c in another place than stator is or not..

@@chetanborkar9898 I think ur more worried for theory rather then concentrating on practical .answer of ur question is @ 10:00 in video

Ya document part also need for inspection and proven the things.. I read IEEE P62.2 in that they written min max difference is not more than 15deg c..

@@chetanborkar9898 difference in temp will depend on extend of core damage.