Discussion in 'Amateur Radio Amplifiers' started by AA7QQ, Jul 3, 2017.
Others may choose not to.
Wow! I practically said the same thing on another thread and got lambasted for suggesting someone homebrew something. I was basically told that unless it was designed by a phd injuneer, it will self destruct and kill everything in the immediate vicinity.
At the same time, some things are already figured-out by an engineer, and are easy to clone. The overtemp sensor I described is one, and can be used to prevent converting expensive silicon to carbon. FWIW, it doesn't have to be used on only water-cooled equipment. It can be placed in the exhaust airflow or on the heatsink of an air-cooled PA. I use the same inexpensive LM35DT device to keep track of the temperature of my air-cooled 1500W dummy load (link).
I choose to try to determine how hard stuff is being pushed, cuz I'm not rich enough to keep replacing expensive parts.
Trust me, in my decades of experimenting, I have created quite a bit of smoke. I always learn from it.
You should hear all the comments about my home brewed beer... "It will kill you from the bad alcohols" "It can carry deadly bacteria" "It is illegal to make moonshine(umm lady I am making beer not booze...), best was a cop who was called, he came up and told me someone driving by said I was making meth I showed him the setup, the grain, then asked if meth is made from grain... dude was going to arrest me until I asked him to get his supervisor. He came up and said "sweet beer brewing setup". Deputy dumb blushed bright red, apologized a couple times... sheriff came by off duty and told me he homebrews so we traded some beer!
It's good that some stuff has already been proven, so we don't have to let the smoke out. We learn from the mistakes of others.
I am looking at using the DS18B20-PAR. It interfaces well with the arduino or R-Pi. I just found it the other day. I can epoxy one to each LDMOS & to the output pipes for each pallet.
That's fine for determining temperature... as long as coolant is flowing. However, what happens if coolant flow stops? THAT's the function of the resistor. When coolant flow stops, it heats the sensor, which then gives you an over-temperature alarm. You want the sensor and resistor to be coupled to the same point on the output pipe.
I'll be using the $5 1/2" sensors from Ebay to monitor flow out of each pallet.
Again, w/o anything else, they work ONLY when coolant is flowing. The resistor, mounted next to the sensor, heats the sensor when coolant flow ceases. Without that, it will take too long for any sensor to output a high temperature condition.