Puls UC10.242 DIN-Rail UPS Guia De Especificação

 

 

UC10.241, UC10.242

 

 

UC-Series 

24V,

 

15A,

 

C

APACITOR

-

BASED 

B

UFFER 

M

ODULES

 

 

 

22.9.  W

HAT DO 

KJ

 AND 

KWS

 MEAN

? 

The units kJ (kilo Joule) or kWs (kilo Watt seconds) is used for specifying the installed storage capacitor size. 

1 kJ = 1 kWs = 1000Ws 

The stored energy of a capacitor can be calculated with the following formula: 

 

Energy ( Ws ) = 

C *U 

2

2 

 

For example: A 350F (Farad) capacitor which is charged to 2.5V has the following energy 

26/27

 

 

*

 

2

 

.

 

5

 

 

= 350F

 

2

 

2

 

=1093

 

Ws = 1

 

.

 

09

 

E =

C * (U1

2

−U2

2

)

 

During discharging of the capacitor, the voltage decreases with the amount of discharge. A boost converter is needed 
to generate a stable output voltage. The boost converter needs a minimum input voltage (cut-off voltage), which 
reduces the amount of energy. The cut-off voltage usually depends on the load current, the lower the load current, 
the lower the cut-off voltage. 
Considering this voltage range, the energy can be calculated with the following formula (full charge voltage= U1= 
2.5V, cut-off voltage= U2= 1V): 

=

350* (2.5

2

−1

2

)

= 919Ws = 0.92kWs

 

2

2

The energy which can be used for the 24V loads is further reduced by the efficiency of the boost converter.  

The UC10.241 has a rated capacitor size of 6kWs and the UC10.242 12kWs. This is the energy which can be used for 
24V load at low load currents.  

Calculation of the needed energy: 

Example: A power of 45W is needed for 2 minutes: 

= 45

  = P * 

W * 120 s = 5400Ws = 5 .4 kWs

 Always check with the buffer time curve (see Fig. 6-1) if the load 

can be powered for the required period of time! 

Apr. 2014 / Rev. 2.0 DS-UC10.241-EN (REVC) 
All parameters are specified at 24V, 10A output current, 25°C ambient and after a 5 minutes run-in time unless otherwise noted. 

www.pulspower.com   Phone +49 89 9278 0    Germany