My relay fails, controlled by Uc

[SimonTHK]

Now I changed the capacitor to 47 times the size with 470n k. Havnt failed yet, but I will be testing it many times and write back here.
As I understood, the snubber takes up some of the load the goes through the switches, and the voltage will increase slower. So my guess was to increase the size of capacitor to increase the time of capacitor charge time.
I ahve very limited time these days, but need it to work so not many great conclusiens to be found right now
If it works, I learned a new thing, and that makes me 10x times stronger in any project in the future.

Thank you

 

[KeepItSimpleStupid]

We basically don't have any real information. We seem to be playing "20 questions"

a) 12 V motor? ratings
b) Some sort of H-bridge with relays
c Relay Ratings?

If the following are true then you can implement a few structures. Anyway coast/brake/fwd/rev are possible states,
For the simple cases, Inputs can be direction and not enable or fwd/rev

You must wait some amount of time when reversing the direction and between stop/starting. You CAN arrange one relay to short out the motor, thus braking it. You can use a DPDT relay for direction and an SPDT relay for ON/BRAKE (No coast mode)

4 relays in an H bridge will give you a coast mode. A ceramic cap at the motor will help with brush noise.

Snubbers (RC networks) may have to go across the relay coils.

 

[Mosaic]

Well the OP did some research based on the discussion and was able to solve his problem, which is better than being told exactly what to do.

 

[SimonTHK]

We basically don't have any real information. We seem to be playing "20 questions"

a) 12 V motor? ratings
b) Some sort of H-bridge with relays
c Relay Ratings?

If the following are true then you can implement a few structures. Anyway coast/brake/fwd/rev are possible states,
For the simple cases, Inputs can be direction and not enable or fwd/rev

You must wait some amount of time when reversing the direction and between stop/starting. You CAN arrange one relay to short out the motor, thus braking it. You can use a DPDT relay for direction and an SPDT relay for ON/BRAKE (No coast mode)

4 relays in an H bridge will give you a coast mode. A ceramic cap at the motor will help with brush noise.

Snubbers (RC networks) may have to go across the relay coils.

I will get back to you with better information for sure.
Also I dont really have great info on my components, just stuff I got from scratch etc. I just really thought a small electric motor that doesnt draw more than 2 amps 12v could be easily controlled by a Uc, transistor and relay, with flyback over relay coils. Apparently not

 

[SimonTHK]

Well the OP did some research based on the discussion and was able to solve his problem, which is better than being told exactly what to do.

It actually did fail, at number 150 times it switched. Though it fails ALOT less, it hasnt 100% sure fixed the problem, which is what I need. Also I get stubborn now.

 

[SimonTHK]

FIXED

https://www.dropbox.com/s/9kkwg76ueta6ym8/svaerdet.jpg?dl=0

So I build a new circuit, and the snubber works now. I changed the values from 20 ohm to 10 ohm, and put on a bigger capacitor 2u2k 373? can anyone tell me what value capacitor that is? I think it is a Metallized Polyester Film Capacitor.

THe reason I changed the values to this. Is that I thought more capacitor to fill would take longer and maybe the 20 ohm resistor prevented too much current to the capacitor, tus doing sparks instead of filling capacitor. I tried with only changing either to a smaller resistor (from 20 to 10 ohm) or a bigger capacitor. None worked, so if I am "guessing right", the smaller resistor with a smaller capacitor, just didnt have enough "room for the current", and the bigger capacitor with small resistor, just couldnt deliver the current fast enough