power supply

[Peyter]

I have a question about a power supply which i have:
When I increase the voltage above 6V I hear a 'click'
from inside the psu. I was curious to what it was, so
I opened the cover and found the there is a relay
inside. What could be the reason for this ?

 

[Lord Garth]

"Peyter" <Peyterxx@btinternet.com> wrote in message
news:bp2k5f$7bq$1@titan.btinternet.com...

I have a question about a power supply which i have:
When I increase the voltage above 6V I hear a 'click'
from inside the psu. I was curious to what it was, so
I opened the cover and found the there is a relay
inside. What could be the reason for this ?

It's probably some form of over voltage protection.
I had some open frame power supplies that would
not power up. Its electronic crowbar was set too low
and this prevented the supply from truning on. There
was an adjustment for the trip voltage though so the
fix was easy.

 

[John Popelish]

Peyter wrote:

I have a question about a power supply which i have:
When I increase the voltage above 6V I hear a 'click'
from inside the psu. I was curious to what it was, so
I opened the cover and found the there is a relay
inside. What could be the reason for this ?

Many linear supplies have a tap changer circuit that selects different
transformer windings as the output voltage is changed to minimize the
waste heat produced by the regulator.

--
John Popelish