The BE242 AMF controller governs the system and transfer the load to generator or utility power smoothly and with a short downtime.
This AMF panel wiring diagram illustrates the connections of BE242 AMF controller, which monitors the parameters of utility power and detects when there are electrical parameters out of range. The BE242 AMF controller will then automatically start the engine via the BE242RB interface board.
The contacts of the relays will instruct the engine to start. Once the generator provides the correct frequency and voltage, the BE242 controller transfers the load from the utility power to the generator. This happens after a mains failure programmed delay (seconds, minutes or hours).
When the engine is cold, the BE242 AMF controller provides a programmable warm up time to run the engine off load. Once utility power has been restored, the BE242 controller will connect the load to the power utility automatically. After a time delay, the engine is then stopped.



The generator is electrically connected to the LOAD via the KG (contactor of the generator). This is possible only when both contacts, KM-AUX and KG-PILOT are closed.
The KM-AUX are the auxiliary contacts fitted on the body of the Mains contactor (so called KM). When the KM is open, the KM-AUX contacts enable the KG.
Once the AMF controller decides to close the contactor, it will energize the relay KG-PILOT. In this case, the coil of the KG will be supplied by the N and L3 of the generator via a protection fuse.
When switching the Generator to Utility Power the user may observe a short ‘power outage’. Normally it is about 2 seconds. This is the typical behavior of the automatic transfer switch: BREAK-BEFORE-MAKE.


The utility power is connected to the LOAD via the KM contactor. The coil of the KM is energized by the closed contacts KG-AUX and KM-PILOT.
The KG-AUX are the auxiliary contacts mechanically fitted on the body of the KG (contactor of the generator). Being the contactor of the generator open, the auxiliary contacts are closed.
TheKM-PILOT is the UTILITY POWER control relay. This relay is OFF when the utility power (or MAINS if you will) is within the settings. In this case the COIL of the KM is supplied by the N and L3 of the MAINS via a protection fuse.
It is really important to note why we use the normally closed contacts of the KM-PILOT . By using the normally closed contacts, we are sure to provide priority to UTILITY POWER in case the ATS controller is damaged or without supply.
If we use the normally open contacts, all the time we remove the DC supply of we remove the battery of the engine, we disable the contactor of the mains. The user will get an unexpected power failure in the building even if the UTILITY POWER is healthy.
This is why we use the normally closed contacts. In case of real power failure, the AMF controller energizes the KM-PILOT. The KM-PILOT contacts will open and the KM will open as well.
This prevents the AMF panel to supply the LOAD with improper electrical parameters.
Once the KM is open, the auxiliary contacts KM-AUX will close. This is one of the mandatory condition to close the KG (the KM must be open in the first place).





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