6kVA Isolated Online UPS

TX91-6K 6kVA / 6000VA Isolated Online UPS

An Isolated Online UPS, also known as Power Conditioned Online UPS or Laboratory Grade UPS, protect against all common power problems.  This premium technology adds galvanic isolation transformer to the online UPS topology providing protection from common mode noise.  Isolated Online UPS are used to provide the cleanest power in difficult applications such as industrial environments, laboratories, and any installation with grounding or noise issues

  • Unity Power Factor 6kVA / 6kW
  • Optional battery runtimes up to 2.5 hours
  • Maintenance bypass
  • Auto restart
  • Hot swappable internal batteries
  • Galvanic isolation transformer
  • Configurable outputs
  • UL1778, cUL, FCC Class A, RoHS
  • Purchase with confidence!  The TX91 UPS is backed by an industry leading 3-year product warranty and a $50,000 Load Protection Policy.
  • For questions or quotations please contact us via Chat, Phone or email at sales@republicpowersystems.com 

Product description

Features of the TX91 6kVA Isolated Online UPS  include:

The TX91 6kVA Isolated Online UPS provides the cleanest power in the most demanding conditions. The TX91 galvanic isolation transformer prevents common mode noise which is left exposed by typical transformer-less online designs.

Galvanic isolation keeps the electrical output from the UPS physically isolated from input power coming into the UPS.  Power isolation is achieved by using isolation transformer.  No output electrical wiring comes in contact with the input power cabling.

  • CAPACITY: 6 kVA / 6000 VA/ 6000 Watts                                                                                            CLICK HERE TO CALCULATE YOUR POWER REQUIREMENT
  • INPUT VOLTAGE: 208VAC (200VAC, 220VAC, 230VAC, 240VAC optional)
  • RUNTIME: 8 minutes @ 100% and 20 minutes at 50% load draw
  • EXTENDED RUNTIME: Up to 153 minutes @ 100% and 394 minutes @ 50% load draw (with additional external batteries)
  • OUTPUT VOLTAGE: 240/120VAC or 230/115VAC
  • EFFICIENCY: Up to 97% ECO mode, 91% online mode
  • UPS TOPOLOGY : Galvanically Isolated Online
  • MANAGEMENT: Intelligent battery management, remote control and monitoring options that are network manageable
  • WARRANTY: 3 years electronics, 3 year battery warranty (USA and Canada)

Benefits of the TX91-6K UPS include:

UNITY OUTPUT POWER FACTOR: TX91 systems provide more real capacity for high density loads

MAINTENANCE BYPASS: Manually transfer critical loads from UPS power to utility power, enabling TX91 UPS maintenance

GALVANIC ISOLATION TRANSFORMER: Eliminates common mode noise and the need to install expensive dedicated circuits and provides power conditioning during normal and bypass operation

EXTENDED BATTERY RUNTIMES: Optional 580W internal batteries (XR models) and external battery cabinets and chargers can be added for extended runtime

STATIC SWITCH: Automatically transfers output from inverter to the isolated bypass source in the event of an overload or fault

SURGE VOLTAGE LET-THROUGH: < 10V normal mode (L-N), < 0.5V common mode (N-G) when subjected to 6kV ANSI/IEEE C62.41 Cat. A

HOT SWAPPABLE INTERNAL BATTERY TRAYS: Easy to replace without interrupting the load

SURGE VOLTAGE WITHSTAND CAPABILITY: ANSI/IEEE C62.41 Category A & B, 6kV/200 & 500A, 100kHz ringwave

$50,000 LOAD PROTECTION POLICY: Offers protection against damaged connected equipment

Power Protection provided by the TX91 6000VA Isolated Online UPS:

  • Power conditions such as electrical surges and sags
  • Total loss of electrical power or hard power “re-boots”
  • Unstable incoming power caused from outdated or faulty electrical wiring and or power distribution equipment
  • Harmonic interference from neighboring “high power draw” equipment
  • Severe weather events such as lighting storms, ice and snow storms and downed power lines
  • Unstable power generation from local utilities or on-site generation

Click here to learn more about the TOP 10 POWER ISSUES and UPS power protection features

Wide Power Input

The TX91 6kVA Isolated Online UPS supports incoming wide AC power input. The automatic voltage regulator (AVR) protects the UPS and connected equipment from adverse voltage conditions. This wide AC input capability can offer sag and surge protection without engaging the backup batteries of the UPS. This will reduce the stress on connected critical equipment and extends the battery life of the UPS.

Double Conversion Topology

Double Conversion Technology

                              Double Conversion Technology

The TX91 6000VA Isolated Online UPS utilizes the Double Conversion UPS topology.  This along with galvanic isolation provides the ultimate in clean and stable electrical power.

Incoming AC power is fed to the UPS’ rectifier converting it from AC to DC power. The converted DC power routes to a battery charging circuit and to the inverter for conversion back to AC power. The resulting “double converted” electrical power is pure sine waveform output providing near perfect electrical power for connected equipment.

To ensure 7/24 up time the true online double conversion UPS topology utilizes a static “bypass switch” within its circuity design. If the TX91 6kW Isolated Online UPS detects a system failure, audible alarms will sound as the bypass switch is engages. This routes power around the failed UPS and ensures critical load power to target equipment.  This very important feature allows for 100% up time for critical equipment while the UPS can be repaired or replaced.

In the event of total power failure, the UPS will power off the rectifier when the loss of power is detected. The UPS’ internal backup batteries will continue to supply DC power to the inverter. There is no transfer time as the transition to battery power is instantaneous. This feature provides true uninterruptible power to mission critical equipment.


Technical Specifications



Rated Power Capacity (Apparent/Active)

6kVA / 6000VA / 6000W

Voltage/frequency range

208VAC (200VAC, 220VAC, 230VAC, 240VAC optional)


240/120VAC or 230/115VAC

Battery Module

(20) 12V 9AH / (20) 12V 580W

Dimensions & Weight

9.9" x 23.3" x 32.4", 278 lbs

Output Connections

120V: 5-15/20R 240V: L6–30R, L6–20R, 6–15/20R, C19
Terminal blocks or optional PDU


UL1778, cUL, FCC Class A, RoHS


RS-232, EPO, RS485, USB, dry contact, (2) slots for optional cards (Web/SNMP, Relay/dry contact)


3 years battery warranty (USA and Canada)
3 years electronics

Whats in the box

User manual, RS-232 communication cable, shutdown software

Available Options

5 year extended warranty, output PDU, input L6–30P cord

Estimated Run-Time

Battery Run Time Graph