DIYbanter - View Single Post - Switch-mode power supply cutting out

Pete Verdon

wrote:

What I'm getting at, is your control gear may be taking a couple of
watts and the 7812 dropper is losing maybe a few watts. Add on a fan
2W load and you could be over the top for the SMPS static power
consumption.

That sounds plausible. As has already been said, the regulator is having
to lose half its input power as heat, plus running a reasonable-size
relay at precisely the time that the fan is pulling most power. Some
parts of the fan assembly were very lightweight, so the thing is clearly
built down to a price.

Sod's law being what it is, the system hasn't cut out since I started
this thread. I'm inclined just to leave it and see if it happens enough
to be annoying. Or is cutting out like this likely to damage the supply?

Cheers,

Pete