Re: SSR question

On Fri, 13 Sep 2024 09:14:59 -0700, john larkin <JL@gct.com> wrote:

On Fri, 13 Sep 2024 21:17:02 +1000, Chris Jones
<lugnut808@spam.yahoo.com> wrote:
>

On 13/09/2024 12:45 am, john larkin wrote:

On Wed, 11 Sep 2024 21:55:57 -0700, John Robertson <jrr@flippers.com>
wrote:
 

On 2024-09-11 8:08 p.m., john larkin wrote:

>
Given a power supply that needs 120 volts AC input, I'd like to use a
small front-panel power switch at some low voltage, not run the AC
line up to the front panel.
>
Do people make SSRs that would do that, accept a low-voltage switch
closure to switch AC?
>

>
Sure, there are the TRAIC SSR bricks that take 4 to 32VDC to switch -
and can handle tens of amps.
>
https://www.digikey.ca/en/products/filter/solid-state-relays-ssr/183?s=N4IgTCBcDaIIIGEAEAXATgSwIYGMQF0BfIA
>
And also the opto-isolated TRAICs like the MOC302x family from Lite-On.
>
Of course you need some power to enable that stuff to run - perhaps a
capacitor/resistor driven supply that sucks a tiny amount of current
from the power line to enable the drive circuit?
>
John :-#)#

 
Yes, I'd need another isolated ACline power supply to make the drive
voltage for the SSR.
 
The alternative is to do what is common, have a giant power inlet
block on the back (IEC, emi, fuses, big switch) and run that into my
24 volt supply, and use the front-panel switch to enable the supply or
switch its output.
 

>
You could use a little generator - the EnOcean wireless wall switches do
that to avoid using a battery. When you press it, the mechanical energy
from your finger powers a tiny generator and powers the transmitter
(either Bluetooth or another standard).
>
If someone would package just the button part that does the generating,
leaving off the radio, it might well make enough power to turn on a SSR
for a cycle or two, which could then power the thing up properly.
>
>

>
Reminds me of an old telephone ringer magneto that I had as a kid. It
packed a pretty good shock.
>
How about a stepper motor with a knob? They make good generators.

Two windings of a stepper could be combined to make a positive voltage
when spun clockwise and negative if spun CCW. That can drive a
single-coil latching relay.