Critical Power Supplies has pleasure in providing you with the following guide for different types of UPS Options.
Typical UPS Options.
Some of the following are built-into specific UPS as standard. Others may be options available on request:
A) GALVANIC ISOLATION
Not all Off-line, Line Interactive and transformerless Online UPS provide Galvanic isolation. This is a separation of the mains and output supply of the system, principally disconnecting the input and output neutral. Without Galvanic isolation on sites with high levels of spikes, transients and electrical noise, the neutral can act as a direct path for the electrical pollution to reach the load(s). Galvanic isolation can be achieved using a transformer (normally housed in a separate cabinet).
Figure 1 : Conneciton of a UPS in Parrallel
B) HARMONIC FILTERS and 12-PULSE RECTIFIERS
Smaller UPS, within the single/single phase category up to 10kVA, typically have a sinusoidal input current waveform and do not generate harmonics into the local mains supply. Harmonics can pollute downstream hardware and prevent synchronisation of the UPS to a generator supply. The problem is typically found with larger single and three phase UPS having a 6-pulse rectifier. The solution is to install a harmonic fi lter in a separate cabinet or change the 6-pulse rectifier for a 12-pulse system.
LOCAL COMMUNICATION Options
FRONT PANEL LEDs
Coloured LEDs provide immediate status indication and are usually sufficient for small single phase UPS
A front panel LCD can provide additional information on UPS, battery and mains operating conditions such as Load %, Battery Charge %, Mains Voltage and Runtime available. Such a facility normally provides access to stored historical logs and operating parameters for on-site customisation.
REMOTE COMMUNICATION USING SIGNAL CONTACTS
If the UPS front panel is not readily accessible, remote signalling may provide operational, historical and diagnostic information, either as simple mains failure and battery low alarms, or as RS232 information to a signal panel, management system or UPS management package.
Using opto-isolators or volt-free contacts, a UPS can be interfaced with the protected voice and data processing system so that system users are notified
of changes in UPS operating status, and to achieve an orderly system shutdown on mains failure.
For more detailed remote information, RS232 transmitted data can be displayed on an alphanumeric panel, terminal or network PC. Communication can be achieved using a standard RS232, RS422 or RS485 serial line (twin pair connection).
For network wide management, a UPS can be managed using the SNMP – Simple Network Management Protocol. SNMP can be achieved using software or hardware solutions.