The Dse500 is an automatic transfer switch control module, designed to monitor the incoming AC mains
supply (3 phases) for under voltage. Should the voltage fall out of limits, the module will issue a start
command to the generating set controller. Once the set is available, the ATS module will control the
transfer devices and switch the load from the mains to the generating set.

Should the mains supply return to within limits the module will command a return to the mains
supply and stop requesting the generator. A clear mimic diagram with ‘International’ symbols and LED
indications provide ‘at a glance’ information as to supply availability and load switching status.

In the event of a mains failure the module operation would normally be as follows:
‘Mains available’ LED extinguishes and the module de-energises the ‘Run Generator’ Relay, causing the ‘Run’ contacts to close. A generator start module receives this signal and initiates the engine start.
Once the generator is running and the ‘Engine Running’ signal is present, the ‘Generator available’
LED will illuminate. The module will then await the ‘Load transfer’ signal from the generator controller, once this is present the Module will then energise the ‘Close mains’ relay which causes the ‘Close mains’ contacts to open, thus opening the mains contactor. The ‘Mains on load’ LED will extinguish. After a short time delay, (Transfer Delay 0.7) allowing the mains contactor to open, the ‘Close generator’ relay is energised causing the ‘Close generator’ contacts to close, thus causing the generator contactor to close. The ‘Generator on load’ LED will illuminate.