Weird continuous sound in relay

Thread Starter

susannah

Joined Feb 14, 2010
87
I have Nagares RLP/4-12 12V-40A 3913 relay and it works okay but it also keeps funny electric buzzing noise all the time when it is powered. And i think i smell electric smoke when i try to use it too.

I'm controlling it using 12V.

Should i use less than 12V or whats going on?
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
If you used AC on a relay designed for DC the relay armature may not be constantly retained due to the AC reversing polarity every half cycle, so the relay tends to start to drop out at zero until the other half of the cycle attracts it again, this causes high current and chatter.
AC relays have a shading coil to help retain it through the normal zero transition.
Max.
 

bwilliams60

Joined Nov 18, 2012
1,442
If you are using 12VDC, you either have insufficient current to power the coil, a bad ground or a bad coil in the relay. Is your power source capable of providing the correct voltage/current?
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
The one thing with DC once it has pulled in it requires much less current to keep it retained.
In large current devices, the supply is often reduced to reduce the P.S. current demand.
Max.
 

alfacliff

Joined Dec 13, 2013
2,458
if you pass the coil current through a normaly closed set of contacts, you have a clasic "buzzer" and that will make a noise as the relay pulls in, breaks the circuit, and drops out, making the circuit again.
 
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