Hi Vic.
I use thes types of relays for many things.
If you have the ones that actuate from 3 to 32 volts , it would be easy to get
some
interferenc from RF dropping the actuating voltage below 3 volts if you are
running
it at 5 volts. The input circuit is opto -isolated so you are running an LED to
fire a triac.
Some of these devices wait for a zero crossing of the line to switch.
If you get interference at a zero crossing spot , the triac would wait for the
next
crossing and you would miss a half cycle......this might be enough to surge the
relay on the next half cycle.
I would suggest raising the actuating voltage so that you have a larger noise
margin or place a reasonably large cap across the input to let it run the diode
for a few cycles should interference drop the actuating signal below 3 volts.
---
Ron
Vic Rosenthal wrote:
> Richard wrote:
> >
> > Solid-state relays around high power RF tend to be problematic.
>
> That turns out to be the answer. After posting my original message, I noticed
> that it did NOT happen when I transmitted into a dummy load, only an antenna.
>
> The acutating voltage comes from a 78L05 regulator which is bypassed both on
> input and output. The wire to the relay box is shielded. In the relay box, I
> added a pi-section filter in the actuating circuit. It didn't help.
>
> Then I realized that there was probably a high RF potential between the
> actuating circuit and the line terminals. I put a couple of 0.001 mf 3KV
> capacitors from the line terminals to ground, and it solved the problem!
>
> I presume that the RF was shutting down the relay, causing the supplies to
> draw
> more current, as Phil suggested.
>
> Thanks, guys.
>
> Vic K2VCO
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