Specifications

3.8.1 VRLA Battery System Example (EXAMPLE using 225 kVA UPS)

a. The battery system shall include a DC landing box (Wall or floor

mounted) equipped with a 600A/500Vdc breaker. The landing box shall

interface the UPS’ DC input to battery cabinets.

b. The battery shall be capable of operating in an average ambient

temperature of 25 °C, with excursions of 16 °C to 32 °C and shall be sized

as follows:

1. float voltage: 405 VDC

(2.25 to 2.27 V/cell)

2. final voltage: 300 VDC

(1.67V/cell)

4.0 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 6

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.

c. Input Power: Rated kVA at 1:1 ratio.

d. DSP based control logic.

4.1.2 Input Current Limit

i) The Converter logic shall provide input current limiting by limiting the AC

input current. Two (2) 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).

The Converter shall be capable of supplying 1 line cycle of overload current

equal to 125% of its full load rating. 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: