An interesting failure mode of the (motor of the) compressor(s), if automatically started with the usual pressure-circuit:
- if there is a short (eg. 1..3 seconds) power outage somewhat before the compressor would auto-OFF (pressure switch is still ON)
- the electric motor can (actually likely) burn. Very annoying, especially if multiple compressors are started from same pressure switch (which is not uncommon)
This is not a problem if the power outage is longer (say, 10 sec, enough time for relief from the small tube)
- or if power outage is short, but pressure switch is OFF (obviously)
Solutions:
- delayed startup
- either manual start, with simple self-holding relay circuit (so it's OFF right after power outage)
- or some electronic or processor delay (like arduino). With RTC (or better: network connection via NRF24L01 radio or serial link - possibly via BT or wifi adapter) can be programmed so it's off at night, or weekends
- maybe an USB-serial adapter in a TP-Link (openwrt) router (also useful as fileserver and printerserver) would be suitable to control the relay (TX, or the RTS signal can be switched from software); Requires some software (perhaps as in OverTCPWireless
5V relay (eg. 230V, 10A) might be useful (usually a small PNP inside, activated by pulling input to GND)