Omron G6K Relay Coil is Polarized?

[Sprig]

I’ve never come across a polarized relay coil winding before.

Anyone know why these are now a thing?

My one guess is that there is some extra circuit for flyback and de-bounce already inside the device.

Anyone?

[PCB_Wiz]

The data does not show any diode, but they do have Latching versions (single coil) and for those, you certainly do need polarity - looks like that info is included on all the drawings.
There might be some slight magnetic biasing, but they do not show both drive directions.
You might need to test a relay carefully, to see if you can measure any asymmetry.
In the meantime, just follow the polarity markings.

[hermit]

I found this and it says the difference is the use of permanent magnets in polarized versions.

generalrelay_tg_e_3_1_3-4(classifications).pdf

Opps: I just found this edit didn’t save last night.

Debounce is listed here:https://www3.panasonic.biz/ac/ae/control/relay/power/difference/index.jsp

[dchisholm]

@Sprig

. . . My one guess is that there is some extra circuit for flyback and de-bounce already inside the device . . . .

It has been quite a few years, but I DO recall seeing relays with internal freewheeling diodes. I don’t recall how that information was represented in the Data Sheet, or schematic symbol.

@PCB_Wiz

. . . they do have Latching versions (single coil) and for those, you certainly do need polarity . . .

In the mid 1980’s I helped design a system that used magnetically latched relays to “remember” the state of some front-panel controls in case of power loss. You energized the relay with one polarity to activate the contacts, and with the opposite polarity to deactivate them. As I recall, the concept was rather effective in the days when there wasn’t any truly electronic non-volatile memory, with more than a few hundred write cycles.

Dale

[davidsrsb]

I have used polarized telecom relays in the past. The built in magnet reduces the operating current.

[SembazuruCDE]

@dchisholm

In the mid 1980’s I helped design a system that used magnetically latched relays to “remember” the state of some front-panel controls in case of power loss. You energized the relay with one polarity to activate the contacts, and with the opposite polarity to deactivate them. As I recall, the concept was rather effective in the days when there wasn’t any truly electronic non-volatile memory, with more than a few hundred write cycles.

I’ve also used latching relays in circuits for a mix-match of these reasons:

• Where there was a safety and/or mission critical reason for a relay not “relaxing” and potentially changing state during an unforeseen power outage.
• Battery powered equipment where there wasn’t enough in the power budget to keep a relay energized.
• High altitude ballooning where the relays had already been flight tested and approved where a solid state solution wasn’t. (This payload was intentionally being flown through areas of high flux loose electrons which might flip the state of an unhardened solid state latch.)

I’ll admit, mostly corner cases…