Slide 23 of 28
   Notes:  
 
EXTERNAL SUPPORT APPARATUS
The C/S will normally be powered from commercial power.  However, control loss at a critical phase could be disastrous at worst, and annoying and expensive at best.  Therefore, an uninterruptable power supply is required.  The time of operation of the C/S and what critical functions must be maintained need to be evaluated to determine if batter power alone or a backup generator is needed.  In either case, a sensing system to detect power loss will switch over to a battery powered inverter.  In the event a backup generator is used, the generator will automatically start, and when ready,  will pick up the load.  The commercial power must be monitored. When is returns,  after a delay to allow transients to settle, the UPS will switch back to commercial power, shut down the generator, and recharge the batteries.