Tescom CL115D Series, User Manual, Page: 17 / 38

13
III. OPERATION
DESCRIPTION
The purpose of the UPS is to provide constant power which is in predefined limits. While the input voltage is in
acceptable tolerances, UPS converts the AC mains input voltage to DC voltage , then inverter stage will
convert to AC output voltage again. If the mains input voltage is no available or out of tolerated limits, the UPS
uses the DC power from batteries and generates stable AC output voltage.
So the inverter stage always produce stable AC voltage and frequency for supplying critical loads connected to
the UPS output.
On the other hand, a static bypass system keeps an AC supply (bypass supply) ready to apply immediately to
the output in case of overloads or UPS failures.
PROTECTIONS INSIDE THE UPS
OUTPUT SHORT CIRCUIT PROTECTION
In the event of a fault on the load , like short circuit, UPS shuts-down the output voltage and do not transfer the
load to bypass to protect the bypass source. To restart after a short circuit ,find out the short circuit on the load
side and disconnect it from the output of the UPS. Then restart the UPS again.
OVERLOAD PROTECTION
An electronic overload protection system is available in the UPS. This protection system has 3 levels:
100%-125% load UPS operates for 10 minutes then transfers the load to bypass (adjustable time)
126%-150% load UPS operates for 1 minute then transfers the load to bypass (adjustable time)
If the load is greater then 150% UPS immediately transfers the load to bypass
FUSES
There are some fuses on the UPS:
Power supply fuse (on-board glass fuse)
Static bypass fuse (on-board glass fuse)
Mains input fuse (S2-MCB)
Battery fuse (S3-MCB)
Output fuse (S1-MCB)
OPTIONAL bypass input fuse (S4-MCB)
BATTERY PROTECTION
Deep discharge protection.
Battery charge current limit (adjustable)
Average battery high protection system provides early warning in case of battery over-charge.
A three level battery voltage protection is used in the UPS , the levels are as follows:
9.6 volts per battery / battery low shutdown protection (adjustable)
10.8 volts per battery / battery low warning (adjustable)
14.4 volts per battery / battery high protection (adjustable)
INPUT PROTECTIONS
PFC converter input power is limited against overloads
Input AC voltage high protection (adjustable)
Input AC voltage low protection (adjustable)
OUTPUT PROTECTIONS
Output AC voltage high protection (adjustable)
Output AC voltage low protection (adjustable)
Electronic current limiting at the UPS output.
Output frequency bandwidth protection (adjustable)
BYPASS PROTECTIONS
Bypass input AC voltage high protection (adjustable)
Bypass input AC voltage low protection (adjustable)