hello
i am not a designer but i have my experiance in repairing stuff and hobbying
i design this to swich 2 transfer pumps that work on fixed time alternating
design criterias are keep it simple cheap and foolproof
an other problem i have here in cambodia is that components are very hard to get by
as you can see in the shematic i made an analoge AND port with 4 inputs
normaly i would use the 4082 but is not availible here
i prefer to use triacs because 220V contactor blocks are the only one that are on the shelf here otherwise 24V i have to order them and wait 4 weeks to get them, not good if one break down and you have to replace them right away
thanks in advance
Robert-Jan