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asjad
Joined: 09 Mar 2004
Posts: 52
Location: Greater Manchester - UK
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| ouput driver |
 Posted: Sun Apr 04, 2004 4:57 am |
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Hi Folks,
I need to turn on a bulb for 12hours and turn it off for 12 hours.
If I use a relay, it means the relay will be energised for 12hours
either in ON or OFF condition
The relay will be handling 240v @ 4A
Will the relay survive?, any alternatives ??
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Best Regards |
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dyeatman
Joined: 06 Sep 2003
Posts: 1935
Location: Norman, OK
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| Will the relay hold up |
| Posted: Sun Apr 04, 2004 8:07 am |
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Yes, the relay will be just fine if you use a continous duty cycle rated contactor.
In an application I have here the relays thta switch 208V three phase stay energized for over 24hrs straght sometimes and others (same model) that open and close several times an hour while switch as much as 15 amps. |
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Neutone
Joined: 08 Sep 2003
Posts: 839
Location: Houston
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| Re: ouput driver |
| Posted: Sun Apr 04, 2004 9:46 am |
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| asjad wrote: | Hi Folks,
I need to turn on a bulb for 12hours and turn it off for 12 hours.
If I use a relay, it means the relay will be energised for 12hours
either in ON or OFF condition
The relay will be handling 240v @ 4A
Will the relay survive?, any alternatives ?? |
The typical failure issues with relays are the contacts burning up from frequent use (sparks) and the coil burning up from excessive heat (sustained use). You should be able to find information on both issues in any relay data sheet. For your application a relay is a resonable solution. There are latching relays that only use a short pulse to switch. I use relays from Omron.
http://www.oeiweb.omron.com/ |
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fireball
Joined: 05 Apr 2004
Posts: 3
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| Posted: Mon Apr 05, 2004 8:54 pm |
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U can try using a low voltage light bulb and have it driven by a very cheap 20V MOSFET that can handle currents upto 20 amps (higher current and highervoltage ones are more expensive) these, u can swtich as many times as you want and have then on for as long as u want as long as the mosfet rating that u use is 1.5 times current rating to that of the light bulb.
Cheers |
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