Automatic Transfer Switch Diagram

automatic transfer switch diagram

In the automatic transfer switch diagram you can observe the Output relays [1], the serial interface [2], single point connection ground advice [3], the optional 'engine running status' provided by the Auto Start module [4],the inputs for the generator and power utility [5], the current transformers inputs [6], the power circuit breaker contactors [7] and finally, the generator AUTO START module [8]. As described before, you can connect the current transformers to the load side.

How to remotely control an automatic transfer switch

As you see on the automatic transfer switch diagram, you can connect a switch for a remote control of the BE28 ATS controller by connecting a configurable input. You can use the serial interface to remotely control the ATS module as well.  To guarantee long-term reliability, we recommend that you avoid grounding the battery minus supply into the ATS control panel box. As a matter of fact, is case to lighting, having two points connected to ground may cause severe damage to cable and maybe not, fire. The battery minus should be grounded to one pint only closer as much as possible to the power generator.

This is the typical automatic transfer switch diagram. The Be28 ATS controller interfaces with current transformers in a way to monitor the current supplied by the generator or power utility. You can read the current flowing in the Load when connected to generator or the power utility. You can set up current overload alarms for the generator only. It is obvious that you can set limits for separate Over/Under voltage and frequency limit for generator and power utility. Despite the fact that the automatic transfer switch diagram presents a 3-phase connection, by programming the correct option, you can arrange a single phase connection. The Be28 ATS controller easily interfaces with  any generator auto start via an automotive relay (see KFS). When KFS energizes, it connects to battery minus the input start of the engine auto start module (see B). When the KFS contact closes, the AUTO START is required to start the engine. Once the electrical parameters are within the limits, the Be28 will transfer the LOAD.

How the automatic transfer switch connects the load


In the automatic transfer switch diagram you see the normally closed contact of the KMC that holds active the power utility  contactor KM is held active. In this way the load is connected to the power utility. When the Be28 requires the connection of the generator, it energizes in a particular sequence the relays KGC and KMC. In this way the contactor of the power utility KM opens and the contactor of the generator KG closes.