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Russell Bull
08/25/05 05:54
Read: 1068 times

#100062 - No buts
Responding to: U Kaz's previous message

The problems with relays are well known and understood. Choosing a suitable relay and protection circuit is much easier than using a triac (in my opinion anyway). If we're talking about a significant amount of current, you'll need a heatsink on the triac which normally negates any size advantage. My background is in power control - more specifically lighting control. So, I've used a few triacs in my time and a few relays. I'm not saying triacs are inherently bad, they are fairly reliable but they need more care and feeding compared to a humble relay. Relays also have a higher demonstrable reliability.

Put it this way, get a 10A relay - garden variety. Feed it 230VAC through a standard C curve din rail 10A circuit breaker into a short circuit. See how many times you can activate the relay before it fails. Now try the same with a 16A triac (40A if you like) - it will most likely fail the first time and generally will not survive past 3 times. Also, with the triac you normally require an optocoupler - these too have issues of wearout. Also look at the cost implications - a 10A name brand relay costs me about AUD$5 in small quantities with a led indicator. An equivalent SSR (solid state relay) is at least AUD$20.

Ask yourself "what is safer"

List of 23 messages in thread
What is a safer?      U Kaz      08/25/05 01:52      
   Think about it      Russell Bull      08/25/05 02:34      
   hmmmm      U Kaz      08/25/05 03:24      
      Why not just use a relay?      Russell Bull      08/25/05 03:30      
         Agree but....      U Kaz      08/25/05 03:37      
            Hmm...      Andy Neil      08/25/05 04:08      
         Relay      Andy Neil      08/25/05 04:13      
      philips      Abhishek Singh      08/25/05 09:47      
   No buts      Russell Bull      08/25/05 05:54      
      Is it rocket science then?      U Kaz      08/25/05 06:09      
         What's non-ideal?      Andy Neil      08/25/05 06:49      
            even with a triac you still need a relay      Erik Malund      08/25/05 07:08      
            Relays      U Kaz      08/25/05 07:57      
               the life of a relay      Erik Malund      08/25/05 08:17      
                  Try this      Steve M. Taylor      08/25/05 09:53      
                  Contactors      Russell Bull      08/26/05 01:54      
                     motor specs      U Kaz      08/26/05 02:20      
                        Mechanical things      Russell Bull      08/26/05 03:37      
                     Yebbut      Steve M. Taylor      08/26/05 05:30      
               Use the math Luke      Neil Kurzman      08/25/05 10:00      
   Dumbass customers      Russell Bull      08/26/05 02:15      
      War Stories - New Thread?      Andy Neil      08/26/05 05:49      
         Since Craig is adept at moving posts, I'      Erik Malund      08/26/05 07:41      

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