An item to toss in your DIYer junk pile?
10 amp 120v relay
This week I received 25 relays I had ordered from an Ebay seller, I wanted to assure I could switch a decent resistive load on a 10 amp, 120 volt AC circuit, so I ordered a 10 amp rated relay. When I got the relays, I was a little surprised that they were not much bigger than my thumb nail, and in addition, the solder pins looked tiny, would they really handle the current? Had I bought something mis-labeled?
I thought about this for a couple of days, and a passing thought was leaving some feed back for the eBay seller.. “your relays look wimpy!” 🙂
Hey, this relay looks small compared to those 30 amp 12 volt auto relays, maybe I need take one apart and see how their contacts are made?
Setting to the left of my desk was a stamp processor, and I was thinking of hooking up a decent load, and letting this relay switch it and have the stamp keep track of the number of closures, would I have smoke in a day?
Then I remembered that junk box that I had tossed a Mr. Coffee controller and power relay in. What did Mr. Coffee use to switch that much current at 120 volts? There it was, a relay with an identical form factor, and using the same tiny pins, and mounted to some fair sized traces on the circuit board. I’m familiar with these coffee maker guts, they were working perfectly when I took the coffee pot apart to look at it after four years of flawless performance. We drink coffee every day, this Mr Coffee left the kitchen because someone wanted a newer looking pot, that’s my guess.
It’s a basic rule in DIY, look and see what others are using, the picture you see above is a Mr. Coffee Pot controller and power control section for the heater, and there’s that same small relay with a 12 amp rating that handles it all, same form factor as the ones I ordered. Over 30 years, we normally get rid of one for reasons other than electrical. So this relay design met our expectations and those of Mr. coffee. No information about the rating for # of relay operations under load, but at the few a day I anticipate, it’ll work fine for my needs.
But there’s more here to study. Mr. Coffee no doubt put an enormous effort into designing a power supply for this processor at least cost, they have six momentary switches for input, 5 LEDS for status, and a nice lighted LCD display, plus an audible alarm!
The processor they used is well documented on line, and it’s the same manufacturer as the battery charger I posted about earlier. You can look up the pins to have a better idea what’s going on with Mr. Coffee and their periphery. Another thing I note, at least in this Mr. Coffee design, the LEDs are on tall posts, the LCD display is the same way, and no doubt it will be easy to de-solder the components, or just cut them off and re-use them for your STAMP or ARDUINO hobby projects.
Totally off topic.. but we did try another brand of coffee pot once, and it was the coffee pot from hell…you can read about it here.
All the best,
George