Hi, I'm new to using AC operated relays. I want to use an AC powered relay to turn a single phase load ON and OFF. The coil of the relay is 230V AC 50 Hz and the load I want to turn on is up to 30A. I'm using a Finder DPDT 230VAC relay. (66.82.8.230.0000)
I have two questions:

1. Do I need to add flyback diodes like DC relays use. At the moment I'm just connecting the neutral and live across the coil and the relay is operating fine.

2. Should I put an inline fuse to the relay coil. It only draws 15mA.

Any help would be appreciated. Thanks

Dermot

 

Diodes should NOT be used on AC relays. If volt spikes are a problem you may use a suitably rated varistor or a resistor and capacitor in series across coil to act as a "snubber".
A fuse is not strictly needed but may help protect wiring if coil goes shortcircuit.

 

+1 on RC snubber.
Max.

 

1. At the moment I'm just connecting the neutral and live across the coil and the relay is operating fine.

2. Should I put an inline fuse to the relay coil. It only draws 15mA.

1. Connecting it with what? A mechanical switch? A triac?

2. I don't think so. More likely to cause nuisance failures than to protect anything.

3. There are relays called, "contactors" that are SPST or DPST made for exactly this purpose. That is, assuming you don't need another circuit powered when there is no activation voltage on the coil. This is a, "Keep it simple" suggestion, but contactors are bulky compared to relays.

 

Thanks guys for the quick and informative replies.

Regards

Dermot