I dont know if this question should have been in the solid state forum, bute its related to my zen 4 amp.....
Im in the proces of assembling the powersupply, and when i connect the toroidial transformer to the mains, my fuse between mains and the transformer blows, with a 3,15 amp fuse it explodes with a loud bang !
I have not connected the secondarys of the transformer, so there is no shorting there.
I measure about 1 ohm across the trafos primarys - that should be ok ?
It also seems that the secondaries ate mesuring properly - i have close to 0 ohms acros two pairs of secondaries.
What is wrong - anybody ??
Thanx alot in advance !
Cheers !
Hans Houmøller
Im in the proces of assembling the powersupply, and when i connect the toroidial transformer to the mains, my fuse between mains and the transformer blows, with a 3,15 amp fuse it explodes with a loud bang !
I have not connected the secondarys of the transformer, so there is no shorting there.
I measure about 1 ohm across the trafos primarys - that should be ok ?
It also seems that the secondaries ate mesuring properly - i have close to 0 ohms acros two pairs of secondaries.
What is wrong - anybody ??
Thanx alot in advance !
Cheers !
Hans Houmøller
Hi Hans
There are two types of fuses - fast blowing fuses (in danish "flinke") and slow blowing fuses (in danish "træge"), and I think that you might be using the fast blowing fuse. I had the same problem with my torodial in the beginning - but then switched to a slow blowing fuse (a torodial transformer has a big starting current).
The 1 Ohm or so in the torodial seems fine and if none of the secondaries are connected in any way I see no problem.
Good luck with the project
Hans Bjergegaard
There are two types of fuses - fast blowing fuses (in danish "flinke") and slow blowing fuses (in danish "træge"), and I think that you might be using the fast blowing fuse. I had the same problem with my torodial in the beginning - but then switched to a slow blowing fuse (a torodial transformer has a big starting current).
The 1 Ohm or so in the torodial seems fine and if none of the secondaries are connected in any way I see no problem.
Good luck with the project
Hans Bjergegaard
1 ohm for the primary seems quite low. I have a couple of toroids at home for this project and I'll measure them this evening.
The other possibility is that you have a shorted loop connected through the center of the toroid. That would act as a shorted secondary and will always blow the primary fuse.
Jeremy
The other possibility is that you have a shorted loop connected through the center of the toroid. That would act as a shorted secondary and will always blow the primary fuse.
Jeremy
Problem Solved !!!
Its working now - I put a ligth bulb in series, and the big dounot is alive
I have another trafo exactly like the first, and they measures the same.
I have 18 volt AC on both secondarys now.
But, I need to couple them in series to get the 36 volts needed for the Z4 - is it just shorting any two wires from each fase, and then I have 36 volts on the remaining two ?
Or should i short live from one fase and zero from the other ?
Thanx for the help - its greatly appreciaeted !!!
/Hans
Its working now - I put a ligth bulb in series, and the big dounot is alive
I have another trafo exactly like the first, and they measures the same.
I have 18 volt AC on both secondarys now.
But, I need to couple them in series to get the 36 volts needed for the Z4 - is it just shorting any two wires from each fase, and then I have 36 volts on the remaining two ?
Or should i short live from one fase and zero from the other ?
Thanx for the help - its greatly appreciaeted !!!
/Hans
This is just a guess based on a dumb experience I once had: Is ther any possability that you have mounted the toroid so that the mounting bolt and other hardware forms a conducting loop that passes through the center of the toroid? If so, this is likely your problem as a current is induced in the loop which has very low resistance.
The exploding fuse sounds like a direct short that tries to pull all available current. The situation above will do that.
The exploding fuse sounds like a direct short that tries to pull all available current. The situation above will do that.
sam9 said:
Yes, I have also heard something about possible problems with the mounting hardware, so I left the toroid on the MDF board without any mounting, in order to eliminate most sources for error. Of course Ill have to change that when I build a aluminium cabinet, but first I must get rid of the buzz and humming
I have skipped the pre-toroid fuse, and have now only the mains fuse - but it withstands the 750 VA toroid and 100.000uF turn on surge with out any problems. Of course this fusearrangement is not permanent. I have fuses between board and the caps......
Cheers !!
Hans
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