During stand by operation the synchronous machine works as a motor. The coupled flywheel stores the kinetic energy.
The electromagnetic clutch is open, the diesel engine is shutted down, but the pre-greasing and the cooling water pre-heating is active.
100kVA to 1.000kVA
Only the two bearings of the synchronous machines are in operation.
When grid fails, the synchronous machine swaps into generator operation mode, the clutch is activated, the diesel is started and the consumer load is taken over, where the kinetic energy of the flywheel bridges the diesel motor without an interruption until the load is fully overtaken.
An external, electric driven radiator-cooler with 2 stages is the standard cooling of the NBDD UPS system for all operating conditions.
The electromagnetic clutch is bushless as it is in all other electrical system components.
The bearings of the system have a contact thermometer for temperature surveillance. A central grease supply system takes over the fully automatic greasing of all bearings of the system.
NBDD – schematic diagram
1 Diesel engine|
3 Electromagnetic clutch
6 Synchronous alternator
8 Grid power switch
9 Consumer power switch
10 Alternator guards
11 By-Pass- Power switch
12 Grid supply
13 User output of UPS
14 Harmonic distortion
15 Voltage peaks
16 Voltage cut-offs