How to realize interlock between two intermediate relays

How to realize interlock between two intermediate relays

                       
Update:2021-06-11
Summary: 1. The method of interlocking two intermediate relays If it is assumed that the relay power supply...

1. The method of interlocking two intermediate relays
If it is assumed that the relay power supply is a power supply that will not lose power for a long time:
The power of the attraction loop of the intermediate relay A must pass through the normally closed contact of the intermediate relay B.
The power of the attracting ring of the intermediate relay B must pass through the normally closed contact of the intermediate relay A.
If the power supply of the two relays is likely to be out of power, magnetic latching relay you need to install a latch on the relay. Otherwise, after the two relays are powered off and powered on at the same time, there will be a problem of grabbing, and I don't know which one is locked. That is, the normally closed contacts of the two relays are connected in series with each other's coil circuit to ensure that only one relay can work at the same time.
2. How to complete the self-locking interlock circuit formed by the relay control relay? At least two relays are required.
Self-locking: the normally open electric shock of the relay itself is connected in parallel with the switch that controls the relay coil; interlocking: the respective normally closed contacts of two relays are connected in series with the coil of the other relay.
Self-locking is to connect the normally open contact of the relay to the start button in parallel, press the start button contactor to pull in, and the normally open contact is turned on. When the button is released, the current is conducted from the contact, which can realize self-locking.
The interlock is to connect the coil A to the normally closed contact of B in series. When B pulls in, the normally closed contact is disconnected, and it is impossible for the A coil to pull in again. Only when B is disconnected, the A coil can be turned on after its normally closed contact is reset and turned on.