Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 01:29 06 Dec 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 : Solar : Solar Off Grid.  PV Solar Matched to Heating Element .

     Page 2 of 2    
Author Message
Murphy's friend

Guru

Joined: 04/10/2019
Location: Australia
Posts: 651
Posted: 08:31am 14 May 2023
Copy link to clipboard 
Print this post

  phil99 said  
Yes, as long as the switching 'on' time is short enough to prevent excessive burning and the 'off' time long enough to extinguish the arc.


Well, maybe. All thermostats are not created equal. If the contacts are slow to open or/and the opening distance is insufficient, it will create a DC arc when the contacts *open*.

Once the arc is established, 'off' time no longer plays any role as long as there is solar power and a load to feed it.
 
Confused
Newbie

Joined: 02/05/2023
Location: Ireland
Posts: 17
Posted: 11:29am 14 May 2023
Copy link to clipboard 
Print this post

Hello Davo99,
             Yes, It was the Arduino board and the caps that I was referring to. I just wanted to get as close to what you  used and any other unit you used.

                                                             JS.
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2155
Posted: 12:39pm 14 May 2023
Copy link to clipboard 
Print this post

  Quote   phil99 said  

Yes, as long as the switching 'on' time is short enough to prevent excessive burning and the 'off' time long enough to extinguish the arc.


Well, maybe. All thermostats are not created equal. If the contacts are slow to open or/and the opening distance is insufficient, it will create a DC arc when the contacts *open*.

I worded that poorly. I should have said the 'on' and 'off' times of the MOSFET. The MOSFET 'on' time needs to be short so that if the thermostat opens while it is on you want the MOSFET to switch off before the arc damages the contacts. The MOSFET 'off' time needs to be long enough to ensure the arc has extinguished and prevent the arc re-striking.

Having the thermostat switch the gate or gate power supply is the safer option.
 
Murphy's friend

Guru

Joined: 04/10/2019
Location: Australia
Posts: 651
Posted: 03:15pm 14 May 2023
Copy link to clipboard 
Print this post

  phil99 said  

Having the thermostat switch the gate or gate power supply is the safer option.


Understood, that is exactly what my system does.
 
Confused
Newbie

Joined: 02/05/2023
Location: Ireland
Posts: 17
Posted: 09:49pm 14 May 2023
Copy link to clipboard 
Print this post

Davo99,
        With what the lads are saying and what you say in your long post. In there
any modifications you'd make.  Any chance of a simple diagram.
                                  J.S
 
     Page 2 of 2    
Print this page


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

© JAQ Software 2024