Select Relay current rating

Thread Starter

maitrey

Joined Sep 4, 2014
57
Hello,

I am using one DPDT relay for my application which gets connected to 3-way switch. How do I select relay's current rating for this? The required voltage is 24 VDC.

Thanks,
 

Tonyr1084

Joined Sep 24, 2015
4,390
The relay should have numbers on it telling you how much voltage it can safely handle and how much current the switches can withstand.

The question is in what you're switching. The relay may require 24 volts to operate the coil but the switches themselves may be able to handle as much as 250 VAC and depending on the relay, could be 10 amps. But that - you'd have to look at its specs.

Are you asking how much current will the 24 volt relay draw? Answer is "Probably not much." Even if the relay can handle switching high current loads, it won't take a lot of current to activate the relay. But in a 3-way configuration I have to wonder if you're planning on leaving it active for long periods of time. You could run into an overheating issue. Using a 24 VDC relay with a 24 VAC source can also be problematic. The things you need to pay attention to is the coil voltage and current draw, the contacts voltage and current ratings. Then don't exceed them.
 
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