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
STOP!! No 10A
With no load at the secondary side the 3.5AT fuse can't blow.
You probably made the wrong connection with the four(?) wires of the primary.
Check that first.
Do you have a variac?
/Hugo
Buhl said:
hmm - should i try to skip the fuse, and hope that the 10 amps mains fuse will take it ??
With no load at the secondary side the 3.5AT fuse can't blow.
You probably made the wrong connection with the four(?) wires of the primary.
Check that first.
Do you have a variac?
/Hugo
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
Normally, a 3.15AT fuse connected the way you did
shouldn’t ‘explode with a loud bang’.
If perhaps the fuse is too small, it rather should just melt.
That's what worries me.
Now, if a 3.15At fuse blows, a 1.6AT fuse will certainly blow.
/Hugo - still wondering what could be wrong
shouldn’t ‘explode with a loud bang’.
If perhaps the fuse is too small, it rather should just melt.
That's what worries me.
Now, if a 3.15At fuse blows, a 1.6AT fuse will certainly blow.
/Hugo - still wondering what could be wrong
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
Re: Problem Solved !!!
Don't short just 'any' wire.
With a little luck there is a drawing of the windings on the trafo.
The two centre wires should be connected together and then you'll have the 36V on the remaining outer ones.
/Hugo
Glad it works.Buhl said:is it just shorting any two wires from each fase, and then I have 36 volts on the remaining two ?
Don't short just 'any' wire.
With a little luck there is a drawing of the windings on the trafo.
The two centre wires should be connected together and then you'll have the 36V on the remaining outer ones.
/Hugo
kropf said: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.
Jeremy
Well, I measured the toroids, and what do you know --- 1.6 ohms.
Jeremy
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: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.
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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