Always
O
n UPS Systems
M0301_N_Series_DM_Manual V1.4 2012-06-12
1
1.0
Introduction
Congratulations on your choice of the Always
O
n NDM Series On-Line Uninterruptible Power
System (UPS). The NDM Series Slimline/Doormount features the very latest, top of the line,
microprocessor technology and IGBT transistors for clean, highly regulated, PWM (Pulse
Width Modulated) True Sine Wave power all in a convenient, lightweight package. This
package allows for the easy installation of the UPS into a compact enclosure or cabinet doors
with the batteries located remotely for simple power conditioning and battery backup retrofit.
For ease of use, the NDM Series Slimline/Doormount utilizes an LCD display to indicate load
percentage, battery capacity, input voltage, output voltage, input frequency, output frequency,
internal UPS temperature and the mode of operation. It also provides self-diagnostics, a
combination On/Alarm Silence/Manual Battery Test button, a combination Off/Bypass button,
and two levels of alarms when the unit is operating on battery.
The NDM Series Slimline/Doormount incorporates an interface port for communications
between a status contact module, with dry contacts and programmable timer relay, or a PC and
provisions to connect an external charger and additional monitoring features described later in
the manual.
1.1.
Modes of Operation
The NDM Series Slimline/Doormount UPS is designed to continuously operate on-
line as a dual conversion system in the following modes:
Normal -
The critical AC load is continuously supplied by the UPS Inverter. The
input Rectifier derives power from a utility AC source and supplies power to the
Inverter while simultaneously float-charging the storage batteries.
Back-Up -
Upon failure of utility AC power, the Inverter obtains power from the
batteries without interruption. There are no interruptions in power to the critical load
upon failure or restoration of the utility AC source.
Recharge
- Upon restoration of utility AC power after an outage, the Rectifier will
automatically restart and supply power to the inverter and battery charger. For larger
battery banks, an external boost charger may be necessary to aid in reducing recharge
time.
Automatic Restart
- Upon restoration of utility AC power, after an extended outage
and complete battery discharge, the UPS will automatically restart and resume
supplying power to the critical load. Also the battery charger will automatically
recharge the batteries. This feature is enabled in the factory and is capable of being
disabled (consult factory).
Static Bypass
- The bypass will provide an alternate path for power to the critical
load and is capable of operating in the following manner:
Automatic
- In the event of the inverter overload capacity being exceeded or
should an internal failure occur, the UPS will perform an automatic transfer of
the critical AC load from the inverter to the bypass source.
Manual
- Should the UPS need to be taken out of service for limited
maintenance or repair, manual activation of the bypass will cause an immediate
transfer of the critical AC load from the inverter to the bypass source. The input
rectifier, inverter, and battery charging operations will be inhibited until the user
transfers the UPS back to normal operation.
