single coil latching relay snubbing

[utimgr]

Snubbing a relay coil is simple, given that the direction of the current is always constant. Just use a diode.

For a single coil latching relay, where you swap the polarity of the control voltage (24VDC in this case)to latch and unlatch, whats the best way to snub the coil? I'm seeing some pretty hefty spikes on switching so it needs something.

 

[btrueblood]

Are you sure the latching relay has only a single coil? Can you swap it for a dual-coil type?

If not, then consider two back-to-back zener diodes, suitably rated for reverse voltage and power dissipation.

 

[ScottyUK]

A bipolar Transil from STM, or a similar device from others? Opposed series-connected zeners?

 

[OperaHouse]

The automotive industry has gone to using a resistor in parallel with the coil given that some bozo might hook it backwards. Size the resistor 5-10 times the resistance of the coil. When I want things really quiet I use a resistor.