Trying to make transformer...

OK, so I am trying to make a transformer for use with USA wall current, i.e. 60Hz AC power. It's intended as an isolating transformer (1:1 ratio), and the secondary side is center tapped. So basically it takes the primary voltage and splits it into two oppositely oscillating sides.

You can see it on the left hand side of my circuit diagram.



So basically, my problem is that I just can't seem to build the darn thing. I got a big iron core (maybe 2 inches diameter) from a friendly professor, and I wound about 200 turns around it, with a 200 turn secondary to experiment with it. I hooked it up to a 10V sine wave function generator, and I measured something like .05V across the secondary. That is seriously awful.

I noticed that when I increased the frequency the voltage would go up, and it would max out at around 50kHz.

I used a small ferrite toroid with about 30 turns on the primary and 15 on the secondary, and I had to turn the frequency up to 40kHz to see a 7.1:4.2 voltage ratio (rms).

Is there any way to operate a transformer at 60Hz? I really don't want to have to build a frequency changing circuit, as I'm already at the limits of my circuit knowledge. What am I missing here?

what you are doing is a 'hit or miss' game.
it will have 'hit' chance of <0.0001%(?)

first ,you must have the specification clearly spelled out.

pry voltage and current.
sy voltage and current.

since freq is 60hz for the reqd VA calculate c/s area.

alreay you have 2inch dia core.(iron core?)

so check whether it fits the requirement.

then calculate Py and Sy turns , Gauge of wires etc.

this is the method

srizbf
21stjune2010

Uh... I'm not sure how to calculate the optimal windings, gauge and the core size. I guess that's probably what I'm looking for? I can change the core if I need to.

I would try and use some program to calculate it, but I don't really feel comfortable doing that when I don't understand it very well. I don't really want this thing to blow up in my face the moment I plug it in...

Primary: 115 V rms (amplitude 160V), whatever current
Secondary: 115V rms (amplitude 160V), about 700mA rms amps

Both at 60Hz.

Take care with those voltage multipliers!

Hello AxeMaster,

do you have program to calculate transformer calculation ?

then why not try it?

Take the advice of Rob B seriously.Dont compromise.

design the transformer and test it alone(without connecting to voltage multiplier).
you will be safe.

srizbf
21stjune2010

ActualLy the efficiency of a transformer increases on increasing frequency. 60Hz is a low frequency. So a transformer working at this frequency should be highly efficient and there should not be any flux leakage and all flux should pass only through the core. In your case the core is an open one. It should be a closed one to reduce flux leakage.
In case of high frequency the core size and all could be reduced and then also it will work efficiently. This idea is actually used in SMPS . There the AC is converted to DC of same voltage and then converted to very high frequency AC and then given to a transformer to step down. There the transformer is small one with less number of turns and small core.
So a transformer working at low frequency should be highly efficient to produce expected output.

if you can design for 50Hz transformer it will work with 60Hz without any problem, actually what you are looking for, a 110V to 220V transformer(110+110 Secondary)?