Scott wrote:
On Sun, 27 Nov 2016 14:22:38 +0000, (Roger Hayter)
wrote:
Scott wrote:
On Sat, 26 Nov 2016 22:57:58 +0000, (Roger Hayter)
wrote:
[snip]
If they are toroidal mains transformers (with no switched electronic
supply) they will be perfectly happy with the LEDs. The problem is that
if the transformers produce 12V AC and the LEDs require 12V DC the LEDs
won't work.
I have now looked at the transformers. They are very heavy, round and
5 inches in diameter. I'm assuming there are no electronics involved
but I could look inside if you could tell me what to look for.
Assuming the output is AC I should think it virtually certain that there
are no active electronic parts. There could be some interference
suppression components but they will come to no harm. Low load will do
no harm to the transformers. As someone said, the low load voltage
might be a little high, but probably not enough to worry about.
Thank you. This is looking very promising. I hitherto assumed that
upgrading to LED would be an impossibility. Could I ask you two more
questions:
1. Is it worth checking the voltage with no load to see what it is?
Check it with a small load, say 5watts. If it is below, say, 13.5 volts
I wouldn't worry. Especially if you haven't got an expensive true rms
voltmeter.
2. Any recommendations about bulbs. Are some more tolerant to
overvoltage than others? (The more expensive ones perhaps!).
No idea, sorry.
A cautionary tale about using a transformer other than the maker's one
with a fan - probably doesn't apply at all to lighting. I have a Vent
Axia Tempra fan and the mains input to their transformer includes live,
and live switched, abbreviated to LS. This was for the usual fan purpose
of supplying power when on timer or using a humidity detector, while the
live switch turned the fan on manually. The terminals on the actual fan
are marked 24v and LS (and 0v, obviously). You might possible assume
that the LS connector required a 24v signal, although this is not that
reasonable, since converting live switched mains to 24v would require a
relay (or two transformers!) anyway. In fact the LS terminal on the
fan is activated by shorting it to 0v, and is connected (directly) to a
PIC input. So 24v was a remarkably bad idea.
--
Roger Hayter