Reply by Bob Engelhardt ●October 21, 20212021-10-21
I Googled it (like I should have in the first place).  There are a 
couple of reasons that a DC relay may be polarized:
- internal flyback diode (as mentioned)
- an internal LED indicator
- a permanent magnet used to augment the mag field
- in a latching relay

My relay does have a LED indicator, so that's what I'm assuming is the 
reason for my polarization.  And not a permanent magnet.
Reply by Tom Biasi ●October 19, 20212021-10-19
On 10/19/2021 4:26 PM, Sjouke Burry wrote:

> On 19.10.21 21:33, Bob Engelhardt wrote:
>> Yeah  ... I guess what I was really wondering was why they would do that.
>>
>>> If the designers marked it, probably would be good to follow that.
>>
> they should do that if a built-in diode is present.
> Also, the plus and minus identify the coil pins.
> 

They may use that package to make units with the diode.
Reply by Sjouke Burry ●October 19, 20212021-10-19
On 19.10.21 21:33, Bob Engelhardt wrote:

> Yeah  ... I guess what I was really wondering was why they would do that.
>
>> If the designers marked it, probably would be good to follow that.
>

they should do that if a built-in diode is present.
Also, the plus and minus identify the coil pins.
Reply by Bob Engelhardt ●October 19, 20212021-10-19
Yeah  ... I guess what I was really wondering was why they would do that.


> If the designers marked it, probably would be good to follow that.
Reply by Tom Biasi ●October 19, 20212021-10-19
On 10/19/2021 11:08 AM, Bob Engelhardt wrote:

> I have a DC relay with the coil connections marked "+" & "-".  Does it 
> matter?  The relay operates with either polarity so there is no internal 
> flyback diode.  It's a 24v, 33ma coil for those who want to know.
> 
> Thanks, Bob

If the designers marked it, probably would be good to follow that.
Reply by Bob Engelhardt ●October 19, 20212021-10-19
I have a DC relay with the coil connections marked "+" & "-".  Does it 
matter?  The relay operates with either polarity so there is no internal 
flyback diode.  It's a 24v, 33ma coil for those who want to know.

Thanks, Bob