NareshBrd,
Pure copper magnet wire is more expensive and also a bit harder to get, but available here.
When it comes to cores, it is very likely that most of the cheap stuff is built from cold rolled steel sheets. For transformers built with such cores and aluminum wire, a 6 amp 30V-0-30V transformer would be available for less than US $10...
For higher quality builds people try to salvage transformers from imported old equipment. They take the cores and use a new bobbin and rewind with good grade copper wire. The cost increases a lot vs the bargain basement stuff, but they claim that they quality is satisfactory.
I was under the impression that the toroidal transformers made in India were of decent quality. As far as I know even Talema has manufacturing done in India.
Pure copper magnet wire is more expensive and also a bit harder to get, but available here.
When it comes to cores, it is very likely that most of the cheap stuff is built from cold rolled steel sheets. For transformers built with such cores and aluminum wire, a 6 amp 30V-0-30V transformer would be available for less than US $10...
For higher quality builds people try to salvage transformers from imported old equipment. They take the cores and use a new bobbin and rewind with good grade copper wire. The cost increases a lot vs the bargain basement stuff, but they claim that they quality is satisfactory.
I was under the impression that the toroidal transformers made in India were of decent quality. As far as I know even Talema has manufacturing done in India.
Last edited:
I have a voltage regulator based on tap switching with relays that died after 20+ years because a monkey jumped into the transformer pole, we got a surge of high voltage.
The toroid used seems to be OK, the control circuit is gone, and the maker removed the IC numbers, and has since gone out of business.
Back burner project, seems to be 4066 or 4093 IC, and BC547 to switch relay coils.
New transformer at the mains has made this superfluous, the regulator was connected to mains so we got stable single phase throughout the plant. Old one gave too much voltage, and there was no tap changer.
Point is that we do get good standard transformers in that type.
The problem is in one - off custom made units, and there everything must match, and due to poor design it fails.
Also, they do not like triac dimming, that is another problem, and also wrong mounting causing a shorted turn.
Better to use E - I cores, and get a well made one.
The toroid used seems to be OK, the control circuit is gone, and the maker removed the IC numbers, and has since gone out of business.
Back burner project, seems to be 4066 or 4093 IC, and BC547 to switch relay coils.
New transformer at the mains has made this superfluous, the regulator was connected to mains so we got stable single phase throughout the plant. Old one gave too much voltage, and there was no tap changer.
Point is that we do get good standard transformers in that type.
The problem is in one - off custom made units, and there everything must match, and due to poor design it fails.
Also, they do not like triac dimming, that is another problem, and also wrong mounting causing a shorted turn.
Better to use E - I cores, and get a well made one.
Beware of 'China Copper'
Copper plated steel wire, then enameled, is used now for small motors, transformers and so on here.
Check at the winding shop on the reel with a magnet before it is wound.
Copper plated steel wire, then enameled, is used now for small motors, transformers and so on here.
Check at the winding shop on the reel with a magnet before it is wound.
If the power at your house is consistently too high voltage, perhaps the power company can fix this? Here in the states, there’s a certain excess voltage above which they’re obligated to drop the tap on the transformer from the HT distribution lines down a notch to give you power closer to spec.