relay failure
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=124113
Printed Date: April 27, 2024 at 1:21 AM
Topic: relay failure
Posted By: megatfauzi76
Subject: relay failure
Date Posted: October 24, 2010 at 9:20 PM
Hai,
Can I know is there any possibilty relay can fail in operating? 30 and 87 connected all the time? What reason can make the relay failure?
Thank You
Replies:
Posted By: KPierson
Date Posted: October 24, 2010 at 10:44 PM
Yes, as relays are electromechanical all relays will eventually fail, although they typically last a very, very long time.
If 30 and 87 are always connected it could be caused by arcing caused by too much current being pulled through the contacts of the relay. This "welds" 30 to 87.
When the contacts stick like that typically striking the relay will "fix" it.
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Kevin Pierson
Posted By: oldspark
Date Posted: October 25, 2010 at 12:12 AM
Or broken coil/solenoid or its connection (85 & 86).
Posted By: megatfauzi76
Date Posted: October 25, 2010 at 1:17 AM
My battery drain out this morning...because of that relay..it for my autostart by pass..ist possible it drain out my battery?
Posted By: oldspark
Date Posted: October 25, 2010 at 3:37 AM
If it is fused at KP suggested, then yes - the load is still connected.
(That's if there is a load - others can advise on autostarts.)
Posted By: howie ll
Date Posted: October 25, 2010 at 5:24 AM
The coil if kept live will typically draw about 1.25 amps, will flatten the average battery in 18-24 hours.
Most Bosch, Tycho, Honeywell, auto relays are rated 15million + ops.
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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.
Posted By: howie ll
Date Posted: October 25, 2010 at 5:27 AM
I should have said it also depends on where it,s mounted, whether or not in the car or engine bay (corrosion) and the angle, i.e. terminals down = gravity and drainage are on your side, also any under hood relay I install, I securely mount it and spray all over with water retarder.
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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.
Posted By: dualsport
Date Posted: October 25, 2010 at 8:57 AM
If your relay is switching inductive load currents near its ratings, the common practice of the suppression diode across the coil for protecting the drive circuit actually makes things harder for the relay, because it delays the opening process of the contacts, when it needs to break quickly. If this becomes a factor, using an additional zener along with the diode protects the drive circuit without causing this delayed turnoff.
Otherwise the increase in the time that current is arcing across the contacts could cause the relay contacts to weld and stick together. If you can't modify the drive circuit and it wasn't just a one time occurrence you may want to try a quality relay with a higher current rating.
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