Hi guys,

i m new to this field & hope this community will help me. i have to use some small hardwired control system to operate two air cooling units. first one should be on for 12 hours and second one should be off during this period and vice-versa for next 12 hours. should i use hardware timer because using PLC will be too costly for such a small control? can i use relays with timer or it should be contactor as voltage is as high as 220-415? can anyone help me with diagram?

 

Unless there is more to your control algorithm than you state, a simple timer and a form "C" relay should do it for you. Set the timer to switch the relay on and off on a 12 hour cycle.

Wire air cooling unit number 1 to the "A" side contact; Wire cooling unit number 2 to the "B" side contact and connect power to the "C" circuit. When "A" is on, "B" will be off and when "B" is on, "A" will be off.

Just set your timer to turn ON and OFF 12 hours apart.

Jerry Miille