Transformer Replacement

[jach362]

any one can rewire there house and any other for that mater with a bit off help from building control  and a small fee

[Andyha]

Hello all

I thought I would drop into this one as it's an interesting topic

Assuming this is a standard transformer (no reason to assume otherwise) it is fairly simple: I have done this myself before where the old panel is not replaceable and the only thing failed is the transformer. I would rather spend what £20 on the transformer that £100 on a whole panel noting though that of the transformer has failed the panel may follow (it can be counter productive to keep old systems going as they will fail totally eventually).  

Things to watch for:

Output voltage of the new transformer: Again assuming this is juYost the transformer (i.e. not a PSU (which includes the transformer plus other components)) This is measured as AC and is normally higher than the DC output. I have in the back of my mind that at 12V DC PSU will have a secondary transformer coil at 19V AC. That might not be precise but it's always higher because of the losses of the PSU.

Output Load. of the new transformer. The new transformer needs to be able to supply the load - often quoted in VA or Watts the new transformer must match or exceed.

Physical size and fixings: This is the most difficult to match in my experience - if you can find a new transformer with the same fixings, sizes and spacing then it is a simple enough drop in. If not use one existing fixing and you may have to drill a hole and use a very short self tapper for the other fixing (assumes two fixings of course). There's little point in taking the box off the wall to get a nut and bolt fixing - if you go to that amount of effort you are close to new panel territory.

 

Make sure you pick up any hard earths - often a round soldered or crimp terminal held in place by the fixed post fixing of the transformer.

 

Make sure you fully isolate the box from the supply - there should be a disconnect unit (fused spur (switched or unswitched)) close by so isolate at that. This is double important if you are having to drill the box to make sure bits of swarfe do not drop into a live connection.

 

Personally I think this is DIY territory - it's not that complex - but I do get the point that in the commercial/professional world it is most likely too much trouble for the value to be gained.

 

Your competency is tested by the results: Still doesn't work - possibly not competent, Bit of a bang or flash - clearly not competent, Years of continued service from the panel - competent

 

Good luck

 

 

   

 

[Peter Perkins]

Hi Andy,

 

Thank you for that expertly, detailed info and for all your time ‘n effort. Will take everything you stated on board really carefully, prior to attempting anything. 
 

Cheers Matey

Peter 

[james.wilson]

to be fair i would replace a transformer. Id worry why it went though. From experience a tx failing points to issues elsewhere 

[al-yeti]

9 hours ago, james.wilson said:

to be fair i would replace a transformer. Id worry why it went though. From experience a tx failing points to issues elsewhere 

This is top answer , tx very rarely fail on alarm panels , the texe psu failed more often , unless that's fixed now ....

[MrHappy]

5 hours ago, al-yeti said:

tx very rarely fail on alarm panels , the texe psu failed more often , 

 

I see the switch mode PSU as pointless innovation... 

 

[sixwheeledbeast]

I see no issue in replacing a transformer especially on more higher end panels but this is an Accenta after all, not a "£100 panel". If they are available new you need to consider the cost of a whole basic panel like that.

It's a linear transformer which would very rarely have an issue unless it's been overloaded or had a surge.

Questions should be asked of the rest of the system for this reason, I agree.

As for competent I would be thinking about ability to not electrocute yourself and others or start a fire, for example.

 

7 hours ago, MrHappy said:

I see the switch mode PSU as pointless innovation...

Elmdene reckon they have got to the bottom of it... I suppose time will tell.

Could pay for themselves in elecy in the long run. I didn't rate the idea initially SMPS are noisy and have discrete components to fail, but energy efficiency is the way it's going.

[aissecur]

If it’s an old system it could of possibly been damaged by the failure to change the 20 year old battery when needed ...! (although this usually damages the charging circuit)