High magnetizing current

[Nayeem1993]

Hi everyone. I'm facing a problem regarding making a controlled DC power supply for my battery charging.
I'm powering two identical transformers salvaged from computer UPS(each 300VA and 240V/6V) with a ac motor speed controller. I connected two cheaper brdige rectifier(each rated at 100A, but I suspect they'll pop if loaded beyond 20A). I haven't still connected filter capacitor at output.
The problem is, both transformers are drawing excessive magnetizing current(each almost 1A) at 130V input and I'm getting an output of 8VDC after rectifier. Even if i run the rectifiers separately current still stays same.
What might be the reason? My suspicion is chopped voltage input for transformer is making them draw more magnetizing current as i did not find significant circulating current between the transformers. I have attached my circuit drawings.
How can I resolve this? Will it help If i connect a 240V capacitor in parallel at the primary side to bypass some harmonics?
Thank you in advance.

 

[IRstuff]

How do you know it's not your triac regulator?

 

[waross]

8 Volts DC from rectified 6 VAC is to be expected. The DC volts will peak at 8.49. The actual voltage will depend on the filtering and the load.
Your transformers may be a type of constant voltage transformer. In that case high no-load current is normal.
By the way, how did you determine that the primary current was magnetizing current and not a high portion of real current supplying losses?

 

[Nayeem1993]

8 Volts DC from rectified 6 VAC is to be expected. The DC volts will peak at 8.49. The actual voltage will depend on the filtering and the load.
Your transformers may be a type of constant voltage transformer. In that case high no-load current is normal.
By the way, how did you determine that the primary current was magnetizing current and not a high portion of real current supplying losses?

1. As far I know multimeters show avarage voltage in DC mode. For the output it should be 2Vp/pi=2.8Vrms/pi. If i subtract the diode drop then the voltage should be lower. Moreover, I did not supply full voltage(131V for 220/6V transformer). So getting 8V is out of question
2. I did not connect any load at output, still the input current was almost 2A. I measured the input current for each transformer at it was almost 1A for each transformer even without connecting load.

Anyway, I separated the rectifier outputs and checked the currents again. It seems second rectifier has almost 9 volt output at 4.6VAC input when I adjusted the transformer primary voltage to 181V and both transformers were drawing 500mA at primary. When i supplied full voltage, output voltages returned to expected values at both rectifiers(5.6VDC at 240V).
Still confused.

 

[Nayeem1993]

How do you know it's not your triac regulator?

Currents at input and output of triac regulators are same. The only thing changed is voltage.