ummarkhayam

 Profile Answers by ummarkhayam 

• Nov 22nd, 2009

 

Affect of Hysteresis loss is mainly 'Energy loss' in transformers and DC machines because its undesirable in these.

shatakshi

• Sep 2nd, 2011

 

Hysteresis losses are frequency dependent. In DC machines, frequency is zero so losses are zero.
they cause additional heating losses.

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 7th, 2011

 

@ above,

You are right in the sense that "Hysteresis loss depends on frequency".
But there is some misconception, like
1. DC machine is having zero frequency (misconception???????, Relax..., I am not saying DC current/voltage is having non-zero frequency). But emf induces in coil of DC machine is also AC, we get DC after treatment with the help of commutator.So,Even in dc machine frequency is considered.
2. Hysteresis loss in DC machine is zero.(Since there is frequency in DC machine, so hysteresis loss will be here too).

OK, Come to the real question........

Wait, Firstly..... What is Hysteresis???
-Hysteresis is property of ferromagnetic material because of which it didn't get demagnetized to zero value once it gets magnetized by external agent & vice versa. demagnetization can be done fiercely by magnetising it in opposite direction.

So, Extra effort is made in bringing them in original situation, this effort leads to Hysteresis loss.
Actually, According to FRQUENCY, magnetic field changes direction, but its core(ferromagnetic) doesn't respond so fast because of hysteresis property and few magnetising energy gets lost to in doing so. This lost energy comes in picture as "Hysteresis loss".

So, this depends on frequency. For sinusoidal AC it depends as directly proportional to "f" & "B^1.6"

shad

• Aug 21st, 2015

 

But in PS Bimra book they said in transformer the hysteresis loss is inversely proportional to frequency..