Specifications

2033D Specification

The Inverter output shall be capable of providing an overload current while

maintaining rated output voltage to the values stated in section 3.4.10. A message

indicating LED located on the control panel shall illuminate to identify this

condition. If the time limit associated with the overload condition expires or the

overload is in excess of the set current amplitude, the load power shall be

transferred to the bypass source without interruption.

4.2.6 Inverter Current Limit

The Inverter output shall also be limited to 150% of rated load current. The two

sensing locations shall operate separately and independently thus providing

redundancy and, in the event of a failure, prevent unnecessary damage to power

transistor components/fuses. Load current above 150% shall cause an immediate

transfer of the load to the bypass source for fault clearing.

4.2.7 Inverter Overload Protection

The Inverter AC output shall utilize electronic current limiting for overload

conditions. The Inverter shall utilize a contactor to isolate its output from the

critical bus.

a. The Inverter fuses shall be the fast acting semiconductor type to clear

faults on the AC buss.

b. The Inverter output isolation contactor shall be located internal to the UPS

module and shall be controlled by the internal UPS module system logic.

4.2.8 Line Drop Compensation

The inverter shall be provided with circuitry such that its output voltage rises

linearly with output current. The rise shall be required to achieve this function, and

it shall not interfere with other requirements of this specification. The purpose of

this feature is to compensate for varying line drop voltage between the inverter and

the critical load.

4.3 Bypass and Static Switch

4.3.1 General

A bypass circuit shall be provided as an alternate source of power other than the

inverter. A high speed SCR switch shall be used to assume the critical load during

automatic transfers to the bypass circuit. The static switch shall derive power from

an upstream bypass feed contactor internal to the UPS module. The bypass circuit

shall be capable of supplying the UPS rated load current and also provide fault

clearing current. The UPS s ystem logic shall employ sensing which shall cause