Can i get a recommendation about choosing a good relay that stands more than 25A safely? I bought a cheap ssr60da that in specs says it resist for 40A but there in no way also i saw that those cheap ones has a different rating mosfet inside maybe 10 or 16A actually. Also i saw a blue 30A mechanical relay module at 5v command that look promising but it is also quite cheap. Does this one worth the money or ehat relay type it should be so i will can safely draw ~ 25 A 230v from it ?
An AC SSR dissipates about 0.7-1W per A switched (typical voltage drop over a TRIAC, which increases with increased current). I just did a quick Google lookup of your SSR type, and the heat sink required for this is notably absent. No way that device will withstand 60W dissipation for more than a fraction of a second. I expect it'd do 3-5A continuous maybe, getting pretty hot in the process.
Here are some relays that can do the job, starting at under $300 (about USD 38). That's a pretty good price. But: what is the actual load you're trying to switch? This matters a lot, especially at this kind of currents. These ratings are for resistive loads (e.g. heaters), not inductive (e.g. motors). Also note the search term: contactor, not relay.
How is this relay related to your customer satisfaction project?
Is not just i didnt want to open another topic
The contactors are used in the fuse panel and are 220v commanded not 5v right ?
I have to use i for switch about 30 led lamps on /off all at the same time
Contactors typically take 12V DC, 24V DC or 220-250V AC as control signal. You can use your cheapo relay to switch the control signal to the contactor when using a 220V coil; or appropriate DC power supply and switch with a MOSFET (n-channel for low side switch).
That are some serious LED lights, if they take some 200W each. Switching them all at the same instant may cause problems due to the massive inrush current into the capacitors of the LED power supplies. Possibly better to have a number of smaller relays, switching with a second interval. An Arduino could have a role in this: a single switch to the Arduino which then in turn starts switching on the lights group by group.
I thought about using this relay for switching ac power to a contactor, but the contactor doesn t get hot , The ac input side is isolated from the switching side ?
Also i may group those lamps and use multiple relays activated by the same signal from arduino ,Can arduino deliver power to more relays to power them up ?
For this case those 30A relays won t work ?
Topic split
Is not just i didnt want to open another topic
Why not ? This is a different subject on an unrelated topic
Using your logic we would have just one topic with everything in which would be a nightmare to follow. That reminds me of using Discord
Note the distinction; a new thread opened on a different piece of a project extensively described (as of course, it should be) and requiring reference to parts of that previous description, is a "cross posting" and must be merged with the first in order not to waste the time of helpers who need to find out many or all of the details explained in that first posting.
If it really is a different project with few if any details in common, then a separate thread saves reading about completely irrelevant details. 
I just got a cheap ssr60da that says work on 60A..
The name instead of fotek is fqfer, i just opened it and i see quite less amount of resin inside, i have 2 BTA24 1000B TRIACS inside and a moc3061
How much amps would u say this ssr will work ?
I tested the ssr mounted on the heated shrink to disipate the heat, i was able ro weld 4, 5 electrodes of 2.5mm without getting just a little hot
alex0512343:
The name instead of fotek is fqfer, i just opened it and i see quite less amount of resin inside, i have 2 BTA24 1000B TRIACS inside and a moc3061
How much amps would u say this ssr will work ?
That's easy - see datasheet of the TRIACs.
They're rated 25A each, dissipating close to 30W in the process. So that 60A is not for continuous use for starters.
How much current does your welder draw, on average?
I have a mma welder and i tested ssr using it at the max 180A welding 4 electrodes and starting many arcs. I believe it s max amperage is 32A but i ve also seen 17.5 i think for continuos draw
So if one triac is rated at 25A that means in total i can draw 50 ? Or is save to draw 25A continuos from them ?
A welder only draws power when you're striking an arc - and that's usually less than half the time you're welding, and rarely longer than 10, 20 seconds at a time. That 18W peak dissipation will then be more like 5-8W average, which should be no problem for a heat sink that size.
As you can see from the datasheet it's 25A per TRIAC. So two in parallel makes for 50A total.
Don't forget to reapply heat sink compound when reattaching those TRIACs to their heat sink.
Good to see those routed cuts in the board, so an attempt was made at proper isolation, but that wire bridge looks seriously dodgy to me to the extent of being a serious safety hazard, almost shorting out four of the total six terminals of the TRIACs.
So having in mind that i payd about 3.5 € for each relay of this type and it seems to work as it should can i use it for controling the lamps instead of the contactor ?
I will use 2 of those ssr for grouping in 2 pears of 15 lamps
That's really cheap for an SSR, especially with such ratings.
Try it and see what happens!
Ok, also i ca measure 220v betwen the contacts when the relay is off until i plug a consumer, may this do led lamps blink, flash ? If i put an incandescent bulb on the circuit it will stop ?
Depends on your actual LED lights.
What happens when you try it?
I didn t tried yet, i have not mounted the ssr in place
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