Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 12:57 29 Nov 2024 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Electronics : Solid state relay and reverse biased diod

Author Message
Rubes
Newbie

Joined: 01/05/2009
Location:
Posts: 36
Posted: 06:12pm 04 Jun 2012
Copy link to clipboard 
Print this post

Attached is my circuit, consisting of 12v dc pump drawing +- 1amp run directly from 40w solar panel which has it own protection diode, pump is switched by optically isolated ssr controlled by arduino my question is, is a reverse biased diode across the load nessasary to protect the power FET in the SSR output from any inductive "Back EMF" pulse that is produced when the pump is switched off, and if so what sort of diode. Currently up and running as is but a bit worried about this issue.



Project is DIY solar hot water heater that is now getting bigger than ben hur, datalogging, ethernet, differential control (freeze protection to be added) etc.
Thanks for any help.
 
Dinosaur

Guru

Joined: 12/08/2011
Location: Australia
Posts: 311
Posted: 07:29pm 11 Jun 2012
Copy link to clipboard 
Print this post

Hi All

Most SSR's have a reverse protection diode built in.
If you nominate the model and make, or Google the relay
it will be easy to confirm.

Regards
Regards
Hervey Bay Qld.
 
sPuDd

Senior Member

Joined: 10/07/2007
Location: Australia
Posts: 251
Posted: 01:23am 12 Jun 2012
Copy link to clipboard 
Print this post

I would expect the diode to be across the motor. Its the cause of the back EMF.


sPuDd..
It should work ...in theory
 
CraziestOzzy

Senior Member

Joined: 11/07/2008
Location: Australia
Posts: 135
Posted: 08:08pm 29 Jul 2012
Copy link to clipboard 
Print this post

if this was my project, throw a schottky diode (rated 3-4 times peak voltage/current dished out by your panels) at the motor, bung in some ceramic cap between the -/+ terminal at your motor and for good measure, toss in an electrolytic at the high voltage end of your relay.

...and a big g'day to all
http://cr4.globalspec.com/member?u=25757

http://www.instructables.com/member/OzzyRoo/
 
Print this page


To reply to this topic, you need to log in.

© JAQ Software 2024