Laptop Battery

[steve_earwig]

This afternoon I shall mostly be changing a transformer at the vet's here. It's for her operating lamp, the existing xformer is supposed to supply 12 volts from mains at 230 volts but as there's about 255 volts coming out the wall, it eats the fragile and expensive bulbs.

As far as I'm concerned this couldn't have come at a better time as we've had 2 poorly dogs, so I'll be getting a big chunk knocked off the bill (again )

I'm just wondering how many volts will come out of it if I confuse the primary & secondary

[Welly]

I figured out that the lead has 3 wires, a Pos, a Neg and a separate small wire (like a comms link kinda thing).

It could be what's termed a 'sense lead', (said Doggy, without even the merest hint of irony).

I think it did say 'sense' or something on the PCB, it's all in the bin now so academic really surely I can be granted some merit for my "well it's broke so I may as well tinker" approach to home electricals?

I even 'fixed' Mrs Wellington's Hair-Straightening apparatus using a similar cut/joint/pvc tape (lots) approach and she was quite pleased I think...........although the lead does look like a snake after swallowing a large Rabbit

[highlander]

surely I can be granted some merit for my "well it's broke so I may as well tinker" approach to home electricals?

Just as long as you have the fire brigade on speed dial and a big bucket of sand on standby, go right ahead

[Welly]

But I have a guardian angel.......

....an RCD

[highlander]

But I have a guardian angel.......

....an RCD

No good if you bypass it though

[steve_earwig]

Or if the current it passes is higher than that needed to stop a human heart...

All diddley done It was all clearly marked, with 11.0v on the secondary and 0, 230v and 240v on the primary. I connected it onto the 240 volt and it's putting out 11.5 volts, dropping to 11.2 volts under load. The socket voltage was just over 240 volts today, so that should cope nicely with the wild fluctuations that we have to deal with

I'm possibly boring you with this stuff but I'm happy, I could really have done it in 10 minutes but I triple checked everything as I wouldn't want to electrocute my favourite vet

[highlander]

Sounds like the Vet should be passing power to their sensitive equipment through a UPS or some other device that can condition the power supply.

[steve_earwig]

I reckon she's got a bit too much in there for an UPS, unless it's the size of the ones we used to have in the exchanges.

It's just this darned light that seems to be the problem, I doubt there's anything like being up to your elbows in a dog's innards doing something intricate and another bulb blows, taking the fuse with it. Ok the owner will pay for a new one, but that's not really the point.

Here's a thing, she has an x-ray machine and developer (I was working right by it and it suddenly spat an x-ray onto the floor ) but the local ER doesn't, so if you need x-rays doing you have to go to Zagreb but your Fido is catered for locally

[Welly]

Nice one Sir,

It's always a bit weird doing electrical work for someone else, like you say more checks than you would normally do yourself.

Quite a good favour to do though, would have cost the Vet quite a bit getting a company in.....