Relay Chattering

by kal22
Tags: chattering
kal22 is offline
Dec4-07, 11:09 AM
P: 6
What causes relay chattering and what can be done to prevent it?
Phys.Org News Partner Engineering news on
Lifting the brakes on fuel efficiency
PsiKick's batteryless sensors poised for coming 'Internet of things'
Researcher launches successful tech start-up to help the blind
berkeman is offline
Dec4-07, 12:00 PM
berkeman's Avatar
P: 39,615
What are your thoughts? What specific circuit are you working with? Is this homework?
russ_watters is offline
Dec4-07, 05:23 PM
P: 21,999
I've dealt with a relay chattering on an A/C unit due to the pressure fluctuations of the reciprocating compressor on the pressure switch that pulled-in the relay... this is very situation specific.

Danger is offline
Dec4-07, 05:59 PM
PF Gold
Danger's Avatar
P: 8,961

Relay Chattering

How is 'chattering' defined? I mean, as in frequency and/or mechanical vibration. If it's really fast, like a buzzer, I'm wondering about a bad connection that causes the primary circuit to fail when the armature moves...?
mheslep is online now
Dec4-07, 11:04 PM
PF Gold
P: 3,021
Two common reasons:
1. When the relay 'makes' the new system load causes a step current drop in the relay drive coil due to an insufficiently sourced system power supply. This causes the relay to 'break', the open load allows the coil current to recover closing the relay again an so on. Decouple the coil drive from the relay load to correct: more head room on your system power supply, separate power for coil and load (usually is anyway for a relay - thats the point) or better local AC coupling caps (careful - can be complicated as you can just create more problems in a tank circuit w/ the coil and caps)
2. A simple oscillation of some kind on the coil (signal side) independent of the load.

Register to reply

Related Discussions
110V relay help Electrical Engineering 8
Continuity Relay Electrical Engineering 5
Help with Relay circuit Electrical Engineering 3
Relay Neurones Biology 2
relay and its application Electrical Engineering 3