 Joined: 25/01/2020(UTC) Posts: 207 Location: istanbul
|
Hi there,
I'm starting out a project with reed relays and would love to hear about your experiences about
1) maximum distance of the magnet to the relay to trigger it
2) size of the magnet
Thanks inadvance ...
Cem.
|
|
|
|
|
|
 Joined: 08/11/2005(UTC) Posts: 3,528 Location: Mullerup, 4200 Slagelse
|
 This can't just be answered in a simple way  You can buy "normal" magnets or "rare earth magnets", also called "neodymium magnets"; the difference in strength is very big, and thus also the usable distance from magnet to reed relay. You can also buy reed relays with different sensitivity specifications......... From Wikipedia: "One important quality of the switch is its sensitivity, the amount of magnetic field necessary to actuate it. Sensitivity is measured in units of ampere-turns (AT), corresponding to the current in a test coil multiplied by the number of turns in the test coil. Typical pull-in sensitivities for commercial devices are in the 10 to 60 AT range. The lower the AT, the more sensitive the reed switch. Smaller reed switches, which have smaller parts, are generally more sensitive to magnetic fields." A good idea if you choose Neodymium magnets, is to cover each magnet in a layer of e.g. 1mm plastic, so you can't connect two magnets "magnet to magnet" without the plastic between them. They are so strong in magnetic strength; but at the same time fragile as glass, so two magnets "slamming together" can cause tiny parts of the magnets to break of, very sharp tiny parts.......... You have to make tests with the parts you have or can get Per. |
If you can dream it, you can do it! I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide. In case this is not legally possible: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.  |
 3 users liked this useful post by Purellum
|
|
|
|
Joined: 25/01/2020(UTC) Posts: 207 Location: istanbul
|
Originally Posted by: Purellum  You have to make tests with the parts you have or can get That's why I asked the question in the first place. I didn't know reed relays came with different sensitivity levels; that was very helpful. Thanks. C.
|
|
|
|
|
|
 Joined: 25/05/2012(UTC) Posts: 57 Location: surat
|
Hi i am going to be using a magnetic reed relay on my layout. The marklin ones are so freaking expensive and the magnets are a total rip off. Hence i was looking at buying of the shelf relays and Neodymium magnets from amazon (link given below ). As neodymium magnets are very strong, i have some doubts. 1) When i install them on the truck of the locomotive (or under the locomotive if there is not enough clearance for installing it on the wheel truck). will the magnetic field cause interference with the digital decoder and speakers in the locomotive. 2) I have a 74924 automatic grade crossing. Will the magnet cause any issues as it passes over the grade crossing 3) I have installed turnout mechanism and digital decoders for my turnouts .Will the magnet cause any issues with the turnout mechanism and digital decoders. Basically wondering if anyone has used the magnets and found any difficulty. https://www.amazon.ca/DIYMAG-Neo...101&sr=1-11&th=1
|
|
|
|
|
|
 Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC
|
Since you have revived 2 old posts to ask this question, I'm not sure which one to reply to.
Anyway, I use neodymium magnets for all of my locos and have never had an issue with the decoders or speakers within the locos. However, due to their strength I have had problems with some of the Maerklin K track switches where the magnet pulls up the point end and it shorts against the loco bottom. This mainly happens with the old design of the 3 way turnouts that still have the built in solenoid drives. Repositioning of the magnet so that the front wheels are holding it down, if possible, usually solves this problem. This was not always possible so I have now rebuilt the turnout so that the magnet cannot lift up the loose end.
With C-track I have not had any problems with the magnets.
|
1 user liked this useful post by PMPeter
|
|
|
|
 Joined: 22/01/2009(UTC) Posts: 14,875 Location: On 1965 Märklin Boulevard just around from Roco Square
|
What tracks are you using ? |
|
|
|
|
|
|
Joined: 25/05/2012(UTC) Posts: 57 Location: surat
|
Originally Posted by: PMPeter Since you have revived 2 old posts to ask this question, I'm not sure which one to reply to.
Anyway, I use neodymium magnets for all of my locos and have never had an issue with the decoders or speakers within the locos. However, due to their strength I have had problems with some of the Maerklin K track switches where the magnet pulls up the point end and it shorts against the loco bottom. This mainly happens with the old design of the 3 way turnouts that still have the built in solenoid drives. Repositioning of the magnet so that the front wheels are holding it down, if possible, usually solves this problem. This was not always possible so I have now rebuilt the turnout so that the magnet cannot lift up the loose end.
With C-track I have not had any problems with the magnets. Well thank you and i use C track and M- Track . So i can see my c track shouldnt have any issues. Though what about M Track
|
|
|
|
|
|
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
