24 Apr 2019, 06:18
24 Apr 2019, 07:06
(23 Apr 2019, 19:19 )Like Ra Wrote: [ -> ]A similar relay, but 3 times cheaper and a bit smaller in size.
Yes. I saw those too. But they start timing on power on and can be turned off again by powering off eg a switch.
The one I ordered has the option of one time start trigger irrelevant of time of power being connected
24 Apr 2019, 07:11
(23 Apr 2019, 19:29 )Like Ra Wrote: [ -> ]My idea was to connect a battery directly to the magnet. Similar to icelocks - battery discharged - you are free. The approximate lock-time can be calculated.
That was my plan too. But I decided I wanted to be able to set it less than approx 1hr if I wanted too.
This will still be the fail safe as 2 x 9v batteries in series will give me 18v giving a stronger hold and the electronics will run from it too. When they run out everything will fail safe.
So even if I chose 15-30 mins.... I’d still be free in 1 hr if something broke.
24 Apr 2019, 07:40
The inspector
24 Apr 2019, 09:25
That is useful to know! Thanks for that! Didn’t realise there were mail order 3D printers!
24 Apr 2019, 10:48
(24 Apr 2019, 07:11 )ltxrob Wrote: [ -> ]2 x 9v batteries in series will give me 18v giving a stronger holdThe magnets can overheat and painfully burn. Been there. I prefer to power a 12v magnet with no more, than 9v.
24 Apr 2019, 14:39
(24 Apr 2019, 10:48 )Like Ra Wrote: [ -> ](24 Apr 2019, 07:11 )ltxrob Wrote: [ -> ]2 x 9v batteries in series will give me 18v giving a stronger holdThe magnets can overheat and painfully burn. Been there. I prefer to power a 12v magnet with no more, than 9v.
Yes it was something I was going to check.
If they do run hot I’ll put a 7812 or 7809 voltage regulator in and run them like that.
Board runs between 16 & 30v so need to have 18v available.
24 Apr 2019, 15:37
Yes 18v for 10 minutes made the magnets get quite hot.
7809 & 7812 regulators ordered.
Will test again on 12v to see if they get hot too.
7809 & 7812 regulators ordered.
Will test again on 12v to see if they get hot too.
25 Apr 2019, 14:23
Ok tested further with 12v and 9v
Ran them both for 10-15 mins each
Neither got as hot as 18v but 12v was still a little warmer than 9v
Should not be an issue with my 3D prints going soft, I’d estimate temperature to have reached 45-50 deg C, while the 18v was probably close to 75 deg and hard to hold.
Ran them both for 10-15 mins each
Neither got as hot as 18v but 12v was still a little warmer than 9v
Should not be an issue with my 3D prints going soft, I’d estimate temperature to have reached 45-50 deg C, while the 18v was probably close to 75 deg and hard to hold.
25 Apr 2019, 14:32
I had 24V electromagnetic cuffs. Had to run them on 12V.