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We are looking for some ideas, we're going to use the BX-24 to control a home electric heating system we're going to use a variable duty cycle with 30 seconds probable being the shortest , we've been looking at mercury relays, would solid state be a better choice? What advantages would there be either way? If a solid state relay shorts does it close or open? Any input on this matter would be greatly appreciated. Larry Vatland

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Living in Puerto Rico I have no idea what a "heating system" is or what its used for. :-) Kidding aside, since you're asking for ideas: look into zero crossing detection with the BX24's A/D converter. One can do lots of things with mechanical relays if arcing is minimized. Solid state relays are better in general, but tend to be pricey, especially if you want to handle large currents. At 10:57 AM 4/18/2001 -0500, you wrote: >We are looking for some ideas, we're going to use the BX-24 to control a >home electric heating system we're going to use a variable duty cycle >with 30 seconds probable being the shortest , we've been looking at >mercury relays, would solid state be a better choice? What advantages >would there be either way? If a solid state relay shorts does it close >or open? Any input on this matter would be greatly appreciated. > >Larry Vatland

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Solid state triacs would be your best bet for what you are doing as mechanical relays would not hold up. What you are proposing is very similar to Current Valves that operate on duty cycles. These devices usually employ 2 back to back triacs or 1 solid state relay (2 triacs in 1 package). I have seen them fail open/ closed / open in 1 one direction and closed in one direction and is usually the result of a shorted heater. Cheers! Brad Watts / AMT E-mail Web www.amt.nb.ca -----Original Message----- From: Larry Vatland [mailto:] Sent: Wednesday, April 18, 2001 12:58 PM To: basicX List Subject: [BasicX] Relays for electric heating system We are looking for some ideas, we're going to use the BX-24 to control a home electric heating system we're going to use a variable duty cycle with 30 seconds probable being the shortest , we've been looking at mercury relays, would solid state be a better choice? What advantages would there be either way? If a solid state relay shorts does it close or open? Any input on this matter would be greatly appreciated. Larry Vatland

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don't use relays. you have the posablity of contacts welding togather. use a kind of triac circet for turning the 120V AC on an off. this can be controled from the bx-01's pins. --- Larry Vatland <> wrote: > We are looking for some ideas, we're going to use the BX-24 to > control a > home electric heating system we're going to use a variable duty cycle > > with 30 seconds probable being the shortest , we've been looking at > mercury relays, would solid state be a better choice? What advantages > > would there be either way? If a solid state relay shorts does it > close > or open? Any input on this matter would be greatly appreciated. > > Larry Vatland > > ------------------------ Yahoo! Groups Sponsor > > ===== Tony Brenke North Tacoma, WA __________________________________________________

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A solid state relay, or a pair of large surplus SCRs is the only way to go. Forget relays. neil wrote: > Living in Puerto Rico I have no idea what a "heating system" is or > what its > used for. :-) > > Kidding aside, since you're asking for ideas: look into zero crossing > detection with the BX24's A/D converter. One can do lots of things > with > mechanical relays if arcing is minimized. Solid state relays are > better in > general, but tend to be pricey, especially if you want to handle large > > currents. > > At 10:57 AM 4/18/2001 -0500, you wrote: > >We are looking for some ideas, we're going to use the BX-24 to > control a > >home electric heating system we're going to use a variable duty cycle > > >with 30 seconds probable being the shortest , we've been looking at > >mercury relays, would solid state be a better choice? What advantages > > >would there be either way? If a solid state relay shorts does it > close > >or open? Any input on this matter would be greatly appreciated. > > > >Larry Vatland > Yahoo! Groups Sponsor [www.newaydirect.com] > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. [Non-text portions of this message have been removed]

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exactly, I once made a coffee pot with computer control - thermocouple measured temp and ssr cut the power - yes - I know - $100 cup of coffee richard ----- Original Message ----- From: "Neil Jepsen" <> To: <> Sent: Wednesday, April 18, 2001 3:37 PM Subject: Re: [BasicX] Relays for electric heating system > A solid state relay, or a pair of large surplus SCRs is the only way to > go. Forget relays. > neil > > wrote: > > > Living in Puerto Rico I have no idea what a "heating system" is or > > what its > > used for. :-) > > > > Kidding aside, since you're asking for ideas: look into zero crossing > > detection with the BX24's A/D converter. One can do lots of things > > with > > mechanical relays if arcing is minimized. Solid state relays are > > better in > > general, but tend to be pricey, especially if you want to handle large > > > > currents. > > > > At 10:57 AM 4/18/2001 -0500, you wrote: > > >We are looking for some ideas, we're going to use the BX-24 to > > control a > > >home electric heating system we're going to use a variable duty cycle > > > > >with 30 seconds probable being the shortest , we've been looking at > > >mercury relays, would solid state be a better choice? What advantages > > > > >would there be either way? If a solid state relay shorts does it > > close > > >or open? Any input on this matter would be greatly appreciated. > > > > > >Larry Vatland > > > > > > Yahoo! Groups Sponsor > [www.newaydirect.com] > > > >

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