A transformer is used for input 220 v 50 hz and output 24 volts.
Can I use it for output 12 v by giving it 110 v 50 hz?

 

Yes.

 

Alternatively you could remove secondary turns.

 

Yes, but its current rating remains the same, even though the voltage has reduced, so its power rating has also reduced.

 

Alternatively you could remove secondary turns.

Removing seco dary turns, what does that mean

 

Yes, but its current rating remains the same, even though the voltage has reduced, so its power rating has also reduced.

In second case, can I give 60 hz instead of 50?

 

Removing seco dary turns, what does that mean

Depends how well it is wrapped, if possible, you remove any outer insulation and take off say 5-10 turns and and see how much drop/turn is and remove accordingly to achieve the final ratio.

 

Removing seco dary turns, what does that mean

It means if the secondary number of turns is X then removing half of the turns will result in half X. In other words, for example, if the secondary consists of 500 turns, removing 250 turns will drop the output approximately half. I'm no transformer expert but I'm comfortable stating removing half the turns results in half the output voltage. But the wire gauge is not going to support the same wattage as it did before. Certainly half the wattage, possibly as much as 1/4th the wattage. Like I said, I'm not the transformer expert.

 

Given that a transformer is built with a specific turns ratio which provides a specific voltage ratio THAT RATIO DOES NOT CHANGE WITH A DIFFERENT INPUT VOLTAGE. So supplying half the input voltage will result in half the output voltage. Post #4 is correct, because the CURRENT rating is set by the wire size.
The transformer EFFICIENCY will be a bit better at 60Hz, than at 50 Hz.

And there is no reason to consider modifying the transformer.

 

I have modified too many to remember in my time, in many cases it is fairly simple, even winding on a complete new winding.
Toroid's are the easiest, They require ~ 2turns/volt, compared to EI which are often up to 5 turns/volt.

 

There are a lot of people who are not well experienced in modifying transformers, and certainly doing it successfully and accurately takes both skill and experience. So while Max has been modifying transformers daily for over 50 years, quite a few folks have never done it at all.
Besides all of that, In another current thread is shown a classic circuit to get both 12 and 24 volts DC from a single center tapped transformer winding. Which is not what the TS asked for but it really is a neat trick.

 

Max has been modifying transformers daily for over 50 years, quite a few folks have never done it at all.
Besides all of that, In another current thread is shown a classic circuit to get both 12 and 24 volts DC from a single center tapped transformer winding. Which is not what the TS asked for but it really is a neat trick.

Everyone has to start sometime!
Another ploy to double the capacity when using half of a CT winding is to open the centre connection, move one of the CT's over, and make them capable of parallel operation.

 

My trick is to look at the stock and pull out the one I need.