Apologies if this is not the best place to post this, but there is this China based company "Songle" that is marketing these relays, and several vendors on ebay, ali-express and others are selling them on convenient PC boards, often touting the usual "for use with arduino, Raspberri PI", etc. Here's a photo of one I've bought a few of to test...
So like a "good little designer", I like to pick components that well exceed my requirements, and these relays say they are good for 30 amps at up to 250VAC (or 240 depending on what nameplate data you read. The relays also have some rather conflicting specs printed righ on them...
30A 250VAC/32VDC
But they are also marked...
1HP 120VAC
1/2HP 240V
30A 240V
Well I need to control a 1HP pool pump motor that draws about 15 amps peak at startup, settling to about 12. But that's a lot of conflicting information on the label! I have downloaded the English data sheet but I am still confused as to how much AC current this relay can REALLY switch. The company has a product link here, where you can also download an English version of its data sheet (PDF). It doesn't offer much help.
But my REAL concern comes not from looking at the numerical specs, but life experience with relays. Looking at physical relay contacts rated for different AC loads, the single contact in the SONGLE simply does not "LOOK" up to the task. The photo of the internal contact made me skeptical,so I finally cut one open to really look at the actual contact. I'm still uneasy.
I realize there have been advances in everything, and I guess if the relay contact is made of some amazingly conductive and electrically durable substance I'm not aware of, maybe it can do the job. I've seen some other industrial load control relays/contractors that also had what I'd consider "amazingly small" contacts, so I don't want to write it off immediately. But currently, I've been using an OMRON (LY4-12VDC) 4 position (10 amp per contact) relay, with all contacts ganged together, and even one of the OMRON 10A contacts looks bigger than the single so called "30 Amp" contact in the Songle!
So I'm writing to ask how I can test the relay to see whether they are vastly exaggerating the specs, without having to field test it for years. It is sealed, so cutting one open surely makes it less likely to live up to its spec. But is there a temperature I should look for (with a sensor) mounted at the contact to determine the likelihood of longevity? The company claims its good for 100,000 operations. With that little contact, and at 30A AC, I'm VERY skeptical!!! It would be MUCH more convenient to use that what I'm doing now. But convenience is not as important as making a reliable product!
Of course if any of you have actual experience (positive or negative) with this relay, I'd liike to hear that too!