Specifications

2033D Specification
7
The system battery shall be sized to provide the specified back-up time to the inverter
when the UPS is supplying 100% rated load. The battery shall be of the VRLA, Flooded
Lead Acid or Nickel Cadmium types.
3.8.1 VRLA Battery System Example (EXAMPLE using 50 kVA UPS)
a. The battery system shall include a DC cable landing box equipped with
sufficient landing provisions to interface the UPS’ DC input to battery cabinets.
b. The battery shall be capable of operating in an average ambient temperature of
25 qC, with excursions of 16 qCto32qC and shall be sized as follows:
1. Float voltage: 540 VDC
(2.25 to 2.27 V/cell)
2. Final voltage: 400 VDC
(1.67V/cell)
4. FUNCTIONAL DESCRIPTION
4.1 Converter
4.1.1 General
The Converter shall convert the incoming AC power into regulated DC power to
supply the inverter input and system battery. The Converter shall utilize the
following technologies:
a. Solid state PWM controlled IGBT power transistors switching at 8
kHz. Switching shall be defined as IGBT turn on and turn off rate.
Doubling of frequency at inverter output shall not be considered as the true
switching frequency.
b. Input Power: Rated kVA at 1:1 ratio.
c. DSP based control logic.
4.1.2 Input Current Limit
The Converter logic shall provide input current limiting by limiting the AC input
current. The line-side current transformers shall be employed as a means of
sensing the current amplitude. The Converter logic shall also be capable of
providing auxiliary current limiting when the logic is signaled to do so via an
external dry contact closure (e.g.; UPS fed from motor generator). It shall also
provide sufficient capacity to provide power to a fully loaded inverter while
simultaneously recharging the system battery to 90% of full capacity within 10
times the discharge time. The DC output current limit values are as follows: