small crack in torroid!!future of torroid?

[sagarverma]

hi SSS
first of all thanks for the reply.

i followed the advise and checked for shorts.to my utter disbelieve,the windings are shorted,primary and secondary of torroid.

but this is when i have rewound the torroid,the previous post of mine tells bout the condition where windings were not short(i always test for shorts to avoid smoke)

this time the windings short(after rewinding).so will change the wires,rewind and post soon.


pic of shorted windings torroid

[mzzj]

Originally posted by sagarverma
hi SSS
first of all thanks for the reply.

i followed the advise and checked for shorts.to my utter disbelieve,the windings are shorted,primary and secondary of torroid.

but this is when i have rewound the torroid,the previous post of mine tells bout the condition where windings were not short(i always test for shorts to avoid smoke)

this time the windings short(after rewinding).so will change the wires,rewind and post soon.


pic of shorted windings torroid

I see that you have uncoated toroid core?
Sometimes they have quite sharp edges that break wire insulation and thats all you need.

I use #400 grinding/abrasive paper to smoothen it with few strokes around, and after that degreasing with asetone+ coat with your choice of coating. It can be polyurethane lacuer, epoxy glue, spray paint etc.

[sagarverma]

Originally posted by mzzj


I see that you have uncoated toroid core?
Sometimes they have quite sharp edges that break wire insulation and thats all you need.

oops!
so coated torroid is better.i was getting coated one for the same price(exactly same),but i went out for uncoated one thinking that the coating will hinder the setting up of flux.

anyways now i have the uncoated core.

mzzj:

can i cover the whole core with cello tape?it will provide a very smooth finishing.core is very big,so won't warm up during the nominal(for it) 300w continous.will cellotape cause any kind of flux linkage problem?

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KARIZMA-JET SET GO......

[sss]

Originally posted by sagarverma

can i cover the whole core with cello tape?it will provide a very smooth finishing.core is very big,so won't warm up during the nominal(for it) 300w continous.will cellotape cause any kind of flux linkage problem?

oh well

it will work , but , there is a special tape for that purpose....check in stores that wound transformers , its yelloy looking tape specially made for transformers .
i use varnish on my core before winding , also covering it with varnish after winding the primary -this also help to elimintae all sorts of ringing ....
anyway , cellotape is not reccomended

[sagarverma]

laa haul villah kuvat

i suppose i should have done more and more and more...... research on torroids b4 buying one.so much so to avoid muliple probs.varnish scratching away to short primary and sec.,ringinging sound due to uncoated core,coated core way better,

i suppose i will have to go and get the core varnished(not my cup of tea),coated or like that.

i like the idea of taping.very much undecided as to what i will go 4 finally.

this particular smps has started to bore me(its hanging loose 4 to 5 months now).its ridled with probs since day one.rectifier fault,improper wire,mosfet overheat n now this transformer prob.

made one 4 car,working very good,a small one as a minor project for college,worked well;;but this one ,,its freaking me out!!