Transfer switch for a battery backup

[CMA.Alex]

I’m in need of some help. I have installed a battery back-up system. Instead of pulling specific circuits to the critical load panel I installed an automatic transfer switch so that when utility power goes out it would transfer the load to the critical load panel. When I went to test the system by turning off the main breaker the ATS never transferred from utility to the critical load (or the terminals where the generator wires would normally land). There was voltage on the critical load side of the switch where normally the generator wires hook up. I am using a Siemens 100 amp transfer switch (basically identical to a Generac). Read online that Siemens ATS will iniatiate from the gen via signal wire on the N1 and N2 (utility sensing) terminals. Since I don’t have a gen what can I do? Is there a way around it? I’m thinking a contactor or relay of some sort? The ATS will operate manually once I turn off main breaker and automatically transfer back when utility is restored.

Thanks for your help!

 

[LarryFine]

It may not switch to the alternate source unless it senses the correct power characteristics.

 

[ATSman]

An ATS will only transfer from the preferred source to the alternate source (or back) if the bus voltage and frequency is within the specified limits of the voltage sensing circuit of the ATS.
You stated that you are using battery backup as the alternate (E) source. If so then you will need an inverter to convert the battery VDC to VAC to feed the alternate side of the ATS. Either the inverter can be energized all the time or it can be switched on using the engine start contacts of the ATS (you will probable have to design a simple contactor circuit to achieve this.)
You also stated that you manually transferred the ATS to E and when you closed the main breaker it transferred back to utility (N.) This indicates that proper V & F is at the N side but not at the E side when you open the main.