I've seen this wired in a couple of panels and though I had access to the wiring diagram it did not show anything other than the DC relay wired to AC lines without showing any rectification. So I took a couple of pictures showing the relays with capacitors connected to their input terminals and concluded that one of the wires must have had a rectifier diode as it looked bulky in one section of it and had heat shrink on it.
So I got to work and wired a couple of them at home and they worked. The reason for the DC relays was to create delay/interlock between the motor starters, ; about 1.5 seconds and .1 seconds. I liked the idea and recently had a need for cheap, small way to modify a control circuit to have a delay between reversing contactors. I wired a small board as shown in the **broken link removed**which was loosely based on what I saw on that old panel and added a resistor the drop the voltage to within relay specs. I hooked it up to a PLC to test it out by energizing on and off continuously for 10 hours. It worked well.
So what I missing? I'm going to wired it up on live panel next week and wanted to make sure I'm not missing something specifically if life cycle is going to be greatly affected.
Cheers
Kal
So I got to work and wired a couple of them at home and they worked. The reason for the DC relays was to create delay/interlock between the motor starters, ; about 1.5 seconds and .1 seconds. I liked the idea and recently had a need for cheap, small way to modify a control circuit to have a delay between reversing contactors. I wired a small board as shown in the **broken link removed**which was loosely based on what I saw on that old panel and added a resistor the drop the voltage to within relay specs. I hooked it up to a PLC to test it out by energizing on and off continuously for 10 hours. It worked well.
So what I missing? I'm going to wired it up on live panel next week and wanted to make sure I'm not missing something specifically if life cycle is going to be greatly affected.
Cheers
Kal