I soldered everything together like in the picture. The relay works as it should
but having it on it gets really hot. What could be wrong? I can't think of
anything but a short circuit since the copper wire is seems to be the culprit.
Also remember that things like motors -both ac and dc - are basic coils of
also transformers - ac- are just two coils of wire next to each other.(
an iron core between them to help the magnetic lines of flux I think, it's
a long time here also !!!)
On Sun, 24 Aug 2008 17:12:37 -0500, "Mark H" <nomail> wrote:
BTW, there's no such thing as a DC transformer. Only a changing
magnetic field (as from a changing current, AC) will generate current
in the secondary. Consider that if a transformer could work on DC, you
could substitute a permanent magnet for the core (and eliminate the
primary). You would now be getting something secondary current) for
nothing, an obvious impossibility.
An iron core is used at normal power supply frequencies. It's made of
multiple thin layers shaped like the letters E and I.
Almost all wire is copper. Plus I think you're misunderstanding short
circuit. A short circuit is one in which some part of the circuit,
usually the load, is bypassed completely or partially.
Plainly your relay (the load) isn't being bypassed completely, because
if it were, it wouldn't be hot.
Do you think there is a short circuit between windings inside the
relay coil? That's rare, and it takes some abuse of the coil to make
it happen. Was this a new relay, one from surplus (working correctly
when it goes out of use), or one from junk which wasn't working right
when it went out of use? If the relay was good when you go it and
you haven't used substantially more voltage than it's rated for, the
odds are very high its still good.
I think it's time you told us more about the device. What are you
using for both sources of power? What are you trying to control with
the relay? What determines if the relay closes or not?
Since it is relatively fine the wire in the relay has quite a bit of
resistance and thus does not make a "short circuit". If the relay is
actually overheating then either the voltage is too high or else you have an
AC relay and your "transformer" puts out DC because it includes a rectifier.
Your "transformer" might also put out more voltage than it says because it
is intended for a higher current load. In other words, your relay and power
source are not compatible. You probably could add a resistor in your circuit
to solve the problem but you have not given enough information to calculate
its value. If you post the information on the relay and the "transformer"
someone could help more.
Almost too hot to touch is too hot; means the voltage to it is wrong.
Coil windings lifetime will be shortened considerable and it could
become a fire hazard as the coil wire coatings begin to melt and short
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