3 Phase Power

2012 After having problems with UPS & Gen set failure due to Neutral failure, did some investigation.
- Failure of Switch-over box.
Features
- double conversion technology - separates the input ac power from the output power
  - Less desirable design is off-line, line-interactive or delta
Important factor
- input power factor of the UPS
- Efficiency at <50% especially important if dual UPS used in data-center.
Installation factors to consider.
- UPS installation design - space cabling etc.
- Redundant configuration n+1
- Downstream earthing system: TN-S if transformer is in ownership and TT if it is not
- Neutral section equal or double to phases
- Different protection to UPS grid connection and by-pass connection
- Over voltage protections downstream and upstream UPS
- Disconnecting switch at UPS output to easy replacement
- Air conditioning system

Switch box's / commutation

Switch from mains power to generator in case of failure or testing.
commutation between the grid connection and the generator
Important neutral schemes
four-pole breaker and therefore, the neutral wire is also sectioned.
- During neutral switching spikes can be experienced, as neutral floats until connected to generator.
- Sollution is to use transformer isolation downstream of UPS, generating new independent neutral.
  - adding a transformer in the by pass (static and dynamic)
Makes
- TELYS
- NEXYS

BACS - Battery Analyze & Care System
- Some can retrofit on current system, add unit to each battery.
Alternate
- Flywheel DC storage system.
  - Riello Fly Wheel 215KW - spinning at 36,000 RPM

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