Modern power relays for 120VAC?

I was thinking about something like a motor or solenoid operated knife=20 switch or rotary switch with wiping contacts. Or even a slide switch. If = the=20 load is not reactive and you are using AC then you don't need fast=20 operation, although it might cause a problem if it's too slow.

How about adding a signal type relay with bifurcated contacts in = parallel=20 and time it so that the big relay closes first and then the smaller=20 low-resistance relay closes and provides the low resistance you need.=20 Reverse sequence on opening. I'm still surprised that power relays can = have=20 so much resistance at 20A that the contacts may dissipate several watts = and=20 get very hot.

Paul=20

pie.

'possum up

I love my spice hot foods, you bet. But i got recalibrated about a year ago: It burned my mouth, then my stomach (first time for that) then it burned on exit for a total of burns three times. That reminded me to properly respect habanero peppers.

?-)

Knife switches would be great. But they are not legit in many cases because they can hang shut much easier than a regular relay.

The the signal relay would get the lion's share of the current, glow red .. orange .. white ... some PVC stench ... *PHUT* :-)

Also, many low-ohms signal relays are gold plated and that plating is going to be largely gone after the first contact action under load

is this close?

-Lasse

That's the kind that overheated :-)

But we are testing 30A and 40A versions right now.

Joerg-

I have not been following this discussion. Has anyone suggested using a Solid State Relay? Perhaps one made by Crydom? I understand they can be obtained for various AC voltages and DC control voltages, even TTL logic level control. I'm not sure what the upper current limit is, but think it may be at least 40A.

Fred

Those are prohibitively expensive and also since they do not physically disconnect stuff they wouldn't work in this app.