@Draco what solid state relays and high current contactors are you using? I have a pool control project in mind.
looking at using this, I don’t think I need a contactor. https://www.amazon.com/Ogrmar-SSR-25-3-32V-24-380V-Solid/dp/B074FT4VXB/ref=pd_cp_60_1
The problem i have with amazon is the lack of a datasheet. Do you know what the pool component draw in terms of current? I have fluke with a current probe we could plug them in individually and make a reading.
A good bit of education in that article.
For a pool motor, you would want a contactor.
This would be my choice. It would handle up to a 1.5hp motor on 120 or 3 hp on 220.
These are also options.
I believe yashedai is correct. The Contractor is better for your application of pool control than the relay. Silicon fets and transistors have their On Resistance fluctuate with temperature. Plus silicon is susceptible to Corrosion and voltage spikes.(so no lighting strikes). I would guess could get a pool wired up with new solid state relays but it would probably cost you a lot.
Something to keep in mind is SSRs have leakage current -ie they don’t totally isolate like a relay/contactor.
Depending on the app, this could be a serious problem.
I’ll look for a app note on this.
Dr Google says about 20 Amps
You also need Heat Sinks on SSR’s
If your referring to the tool lockouts in the woodshop. I have one SSR
and the rest are using contactors from CBI Electric but I am looking for potential alternatives.
If you going to be switching your pool parts on and off about 5 hz maybe you need a solid state relay but if no ahhhh… In general i use a solid state relay to control a heater bed with a 3d printer i am making because of its high frequency.
The plan is now Contactor for Pool pump and another for pool cleaner accessory pump. ORP sensor for Chlorine level, Ph Sensor, Analog pressure sensor to detect backpressure. Sensors will be connected to ESP8266 running on 5V DC input. Sensor data/Motor control and settings changes will be proxied via wifi to a python controller on a Pi sitting in a DMZ subnet. Readings and settings changes will be accessible from that controller via XMPLRPC to get/set. I’ll write an Android App to control it from my phone - which will interface with controller via authenticated XMLRPC. I’ll NAT that IP/Port to the internet in pfSense and be able to check/change settings for my pool from anywhere. The controller will also have a separate Scheduler thread to turn pumps on/off according to specified settings. The controller will be event driven (inspired by @Draco 's RFID Keymaster) and when settings go out of bounds it will send a text message to me telling me service is needed and/or send a notification to the Android App. I’ll also create a PHP web interface for the controller using the same XMLRPC interface to allow management from a web browser.
Let me know your thoughts.
OK here’s some SSR app notes - probably more than you ever wanted to know
Given that this system is operating around/with water, all circuits, pwr, etc. are downstream of some kind of GFI. There’s probably some kind of electrical code you need to keep in mind.
Yeah it’s all GFI’d
Excellent project… COOOOLLL
FYI the ESP 8266 runs on 3.3 volts so be sure to convert and use logic level converters
I could likely give you some esp8266 if you want them.
I have several but I appreciate the offer
Lots of consumer and industrial controls use 24vac contactors with a 24vac transformer, triac control from 5v or 3.3v, and a 24vac to 5v or 3.3v power supply. This is how every sprinkler and pool controller are constructed. My pool controller uses this $15 contactor:
It was my understanding that the leakage current isn’t between the low voltage side and the high voltage side but that the relay may not turn off completely and have current leaking through.
It is also my understanding that you can fix this issue by putting a correctly sized resistor parallel to the load.
For what it’s worth I’m a big fan of Opto 22. I’ve seen their controllers function perfectly after being beaten to shit from over temperature related stress, vibration, and physical damage.