Blowing fuses.

Thread Starter

jturner410

Joined Jan 10, 2023
11
The toroidal transformer appears correctly mounted (using a mounting kit) with damping material beneath the top securing plate. Having the connecting wires at the mounting surface is normal practice – I very much doubt over tightening of the securing bolt has squashed the wires, causing the issue, since the enclosure is made of plastic.

All the toroidal transformers I’ve seen are wound with the secondary wires wound above the primary wires on the toroid. Personally I think there is likely a short within the transformer (either in the primary winding or one of the secondary’s) – which will need replacing. Once you remove the transformer, there may be an indication of the damage location.

If you are lucky there will be a rating label on the transformer side wall listing the electrical ratings (input voltage, with each secondary output voltage and current rating) – if you are even luckier, you will find a replacement transformer having the required input voltage and secondaries.
It does have the rubber bushing under the large washer plate. I didn't see any visible issues. Should I be getting no resistance if I measured the two red wires? I'm getting 4.6
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
It does have the rubber bushing under the large washer plate. I didn't see any visible issues. Should I be getting no resistance if I measured the two red wires? I'm getting 4.6
That about right, but a resistance reading on a transformer is not definitive, unless it measures open, of course.
If you ever need a replacement, this guy sells them and even makes a custom model if needed
 

Hymie

Joined Mar 30, 2018
1,277
Given the good condition of the transformer, I’m somewhat surprised that it has failed - normally I’d expect to see some overload heat damage.

The 2A input fuse should have protected it from excessive heat damage – that would have been evident anyway. Maybe the country of manufacture is a clue to the transformer’s quality.

If it was me, I’d want to waste one more fuse on powering the transformer outside the unit to confirm that the primary fuse blows with no secondarys connected – confirming that the transformer is toast.

Once you find the cost of a replacement transformer, you can decide whether it’s worth the cost – of course you could supply the secondary voltages via 3 separate transformers as long as the output voltages were the same and the current rating the same (or greater), which may work out cheaper (but they might be a tight fit in the enclosure).
 

Thread Starter

jturner410

Joined Jan 10, 2023
11
Given the good condition of the transformer, I’m somewhat surprised that it has failed - normally I’d expect to see some overload heat damage.

The 2A input fuse should have protected it from excessive heat damage – that would have been evident anyway. Maybe the country of manufacture is a clue to the transformer’s quality.

If it was me, I’d want to waste one more fuse on powering the transformer outside the unit to confirm that the primary fuse blows with no secondarys connected – confirming that the transformer is toast.

Once you find the cost of a replacement transformer, you can decide whether it’s worth the cost – of course you could supply the secondary voltages via 3 separate transformers as long as the output voltages were the same and the current rating the same (or greater), which may work out cheaper (but they might be a tight fit in the enclosure).
So you're suggesting throwing another fuse at it with red wires connected and disconnecting the secondaries? Just to confirm.
 

Hymie

Joined Mar 30, 2018
1,277
While you have the transformer out, carefully inspect the connecting wires for any missing insulation that may be shorting, especially the primary leads.

With regards replacement transformer(s) it/they need not be toriodal types, which tend to be more expensive.
 

Hymie

Joined Mar 30, 2018
1,277
This is the Chinese company that made your transformer:-

https://www.eaglerise.com/

They have a search function, but inputting the model No. of your transformer (HI.BB-0100-0003) brings up nothing.

They may be willing to sell you a one off – but they look like a company that makes bespoke transformers (such as yours) for industrial clients, and it is likely that it was from a one off production run for a specific client (that they no longer manufacture).

The output voltages are non-standard at a 10.1V centre trapped, plus a 9.3V and an 11.1V secondary. If you have to replace the transformer, I reckon that you could get away with the 9.3V and 10.1V secondaries supplied at 9V and the 11.1V supplied from 12V.
 
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