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Can solid state time delay relays handle 12vdc as well as ac loads?

Can solid state time delay relays handle 12vdc as well as ac loads?

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  #1  
Old 07-10-12, 01:43 PM
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Can solid state time delay relays handle 12vdc as well as ac loads?

Looking at industrial type adjustable delay time in the .01-.02s increments. While I find listings for 12vdc input (control) side of relay, all the load side specs are listed as, say, 120/240vac or some fractional hp motor rating. Just don't know enough about ac to know if they will work for battery supply 12vdc 10a load.
Thanks in advance for any help or advice.
 
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  #2  
Old 07-10-12, 01:52 PM
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No expert...but yes...they should work fine. Get the load amps in the range you need.
 
  #3  
Old 07-10-12, 03:08 PM
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There is another idea about using an ac rated switch for dc.

Switches for dc power are rated a bit differently than for ac current.
When dc is switched under load there is a longer arc produced than with ac.
The fact that at one point in the ac power cycle the voltage is at zero, when a switch is opened the arc produced tends to be smaller and arcing causes contacts to burn.
Dc switches need to allow for a longer arc and would have slightly different characteristics than an ac switch.
I use ac switched for dc on occasion but would use one that has at least 50% more capacity that what I'm switching.

There is more.

You need to be careful what type of time delay you are buying.
If it is a time delay/relay combination you need to be sure that it contains a mechanical relay.
There are some relays that use dc to activatethe timer function but have electronic components that can only switch ac...........some hvac relays are like this.
 
  #4  
Old 07-12-12, 02:36 AM
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Thanks so much for the replies. Based on this advice have purchased an Omron digital display timer/relay (settings in .001s increments, even better) w/mech relay output rated for 5A at 30vdc. Should handle my .27A at 13.3vdc load just fine.
Thanks again for steering a newbie in the right direction.
 
  #5  
Old 07-12-12, 08:12 PM
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Thank you for coming back to post your thanks, and the decision you've made.
 
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