Accratech » Isolated Medical Grade UPS

 Linear/1 UPS Isolated Medical Grade UPS: (formerly the Best Unity UPS)


Uninterruptible power supply UL-approved for use in hospital, medical, and laboratory power applications requiring low leakage(less than 100 micro amps) UPS power systems for human interfaces.

Linear/1 is an isolated, medical-grade UPS designed for the demands of professional service. The linear/1 features no-break transfers, high surge capability, multiple voltage outputs and ultra-low leakage current to minimize patient risk.

The Linear/1 is designed to be compatible with all modern loads and is especially suited to today's power-factor corrected equipment requiring Unity power factor.

  • UL544 standard for hospital grade, medical grade, and ideal for dental equipment use.
  • Designed for linear and non-linear loads
  • Unity Power Factor
  • Single Phase pure sine wave UPS

Linear/1 UPS

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  • Ordering Information
  • Comparison
  • Features
  • Gallery
  • Plug Types
  • Using a UPS with a Generator
Model Capacity (kVA/kW) Dimensions (H x W x D) Input Connection Output Connection Typical Runtime (minutes)
in mm 100% 80% 50%
U91-1.0k 1kVA/1kW 5.25 (3U) x 17.75 x 24 133 x 451 x 610 5-20P Hospital Grade (3) 5-15R Hospital Grade 8 12 22
U91-1.5k 1.5kVA/1.5kW 5.25 (3U) x 17.75 x 24 133 x 451 x 610 5-20P Hospital Grade (3) 5-20R Hospital Grade 5 6.5 12
U91-3k 3kVA/3kW 29 x 10.5 x 25.75 737 x 267 x 654 Hardwired input is standard (line cord options available - contact factory) Hardwired input is standard (receptacle options available - contact factory) 13 18 35
U91-4k 4kVA/4kW 29 x 10.5 x 25.75 737 x 267 x 654 Hardwired input is standard (line cord options available - contact factory) Hardwired input is standard (receptacle options available - contact factory) 9 12 24
U91-5k 5kVA/5kW 29 x 10.5 x 25.75 737 x 267 x 654 Hardwired input is standard (line cord options available - contact factory) Hardwired input is standard (receptacle options available - contact factory) 6.5 9 18
U91-8k 8kVA/8kW 32 x 13 x 33 813 x 330 x 838 Hardwired input is standard (line cord options available - contact factory) Hardwired input 11 14 25
Model U91-1.0k U91-1.5k U91-3k U91-4k U91-5k U91-8k
Capacity (kVA/kW) 1kVA/1kW 1.5kVA/1.5kW 3kVA/3kW 4kVA/4kW 5kVA/5kW 8kVA/8kW
Dimensions (H x W x D) (inches) 5.25 (3U) x 17.75 x 24 29 x 10.5 x 25.75 29 x 10.5 x 25.75 29 x 10.5 x 25.75 32 x 13 x 33
(mm) 133 x 451 x 610 737 x 267 x 654 737 x 267 x 654 737 x 267 x 654 813 x 330 x 838
"Weight (lb) 80 84 280 280 295 490
(kg) 38 37 127 127 134 222
Input Connection 5-20P Hospital Grade Hardwired input is standard (line cord options available - contact factory) Hardwired input
Output Connection (3) 5-15R Hospital Grade (3) 5-20R Hospital Grade Hardwired input is standard (receptacle options available - contact factory)
Typical Runtime (minutes) (full "100%" load) 8 5 13 9 6.5 11
(80% load) 12 6.5 18 12 9 14
(half load) 22 12 35 24 18 25
AC Input Voltage Range 75-132 147-264 (for nominal 200/208/220/230/240V output)
Input Nominal Current at Full Load 100V=14A 100V=9A 200V=17A 200V=22A 200V=28A 200V=45A
  110V=8A 208V=17A 208V=22A 208V=27A 208V=43A
  120V=7A 220V=16A 220V=20A 220V=25A 220V=41A
    230V=15A 230V=20A 230V=24A 230V=39A
    240V=14A 240V=19A 240V=23A 240V=38A
Operating Frequency   50 or 60 Hz nominal
  On line: output frequency tracks input within adjustable limits (±3Hz default)
  On inverter: ±0.15Hz
Nominal Output 100/120 nominal output voltage 100/110/115/120/200/208/220/230/240 nominal output voltage
Output Voltage Regulation   ±5% of nominal output voltage
Output Voltage Waveform   Sinewave, computer-grade power with 5% THD at rated kW load
Overload Capacity 200% surge 200% Surge for a minimum of 2.5 seconds / 110% Surge for a minimum of 10 minutes
Transfer Time   0 mS
Lightning, Surge and Noise Protection 110 Joule 200 Joule surge suppression rating. 0.7% Let-Through-Voltage (LTV). Tested to ANSI/IEEE
  C62.41 Categories A3 and B3 tests. Common Mode - up to 50dB. Normal Mode - up to 90dB.
  Separately derived power source per NEC Article 250-5d.
Efficiency (on line)   95% 95% 96% 96% 96%
Recharge Time (to 85% charge) 2-3 hours 3-4 hours
Safety Certification UL 544 (UL 2601), UL 1778, cUL UL 2601-1 / UL 60601-1, UL 1778, cUL
EMC Compliance FCC-B, CISPR 11 FCC-A, Vfg 243/1991, Vfg 46/1992, CISPR 22
Testing Standards   ANSI/IEEE C62.41 (1980), C62.45 (1987); IEC 801-2, 801-3, 801-4, 801-5
Communication   RS-232 port (DE9) featuring full-duplex serial communication, alarm contacts, inverter contacts, and remote shutdown
Operating Temperature 0 degrees to +40 degrees C
Storage Temperature -20 degrees to +60 degrees C (-20 degrees to +40 degrees C if battery is not removed)
Relative Humidity 0 to 95% without condensation
Audible Noise at 1 meter <40dBA
Heat (on line) (BTU/hr) 270 539 569 711 1138
(kW/hr) 0.08 0.158 0.167 0.208 0.333
Altitude Maximum ambient operating temperature drops by 1 degree C per 305 meters (1000 feet) above sea level, maximum elevation being 3050 meters (10,000 feet).

 Due to continuing product improvements, specifications are subject to change without notice.
 Receptacle options (other options available on request)

Compliance with universal safety and EMC standards

3K - 8K models:

  • UL544, UL2601-1 / UL60601-1 medical safety certifications, cUL
  • FCC part 15: Class A, Vfg 243/1991, Vfg 46/1992, CISPR 22 EMC compliance, UL 1778, CAN/CSA C22.2 No. 107.1-M91
  • Hospital-grade plugs

1.0K - 1.5K models:

  • UL2601-1 / UL60601-1, cUL, UL 1778
  • CAN/SCA C22.2 No. 107.1-01, CAN/CSA C22.2 No. 601.1-M90; FCC part 15: Class B for home or office use; CISPR 11 EMC compliance

Low current leakage for "near patient or staff" applications

  • Less than 100 microamps typical... industry safety standards require less than 500 microamps


  • 96% efficient, which may in some applications save you thousands of dollars in energy consumption and AC expenditures
  • Line interactive UPS Not Double conversion so you get true isolation from the load
  • 3 year warranty


  • 1.0, 1.5, 3, 4, 5, and 8kVA/kW industry exclusive offering
  • 5 minutes (1.5K) to 13 minutes standard at full load (with extended runtime options) batter run times for power loss situations... be they planned or not
  • 1.0 and 1.5k: 100-120V input, 100/110/115/120V output
  • 3 - 8k: 200-240V input, 100/200/208/240V output
  • 1 to 4 plug and play panels with multiple receptacles in each

18 internal diagnostic routines

  • Comprehensive UPS condition alerts: low runtime, overload, circuit breaker warning / shutdown, high ambient temperature, check battery, check inverter, memory error, high battery, low battery advisory condition, check fan, batteries disconnected, tap regulator alarm, low AC out warning / shutdown, high AC out warning / shutdown, check MOVs, auto bypass, check fuse board, check power supply

Unity power factor

  • No oversizing of UPS is required for power factor corrected loads

System superiority

  • Realtime multi-tasking microprocessor control
  • Worldwide voltage and frequency compatibility
  • Lowest operating cost in its power range
  • 40 decibel at one meter audible noise (5 times softer than other offerings)
  • Easy installation

Software suite included with 3K - 8K models

  • The LinCS Software Suite is a comprehensive collection of power management shutdown software for use with linear/1 uninterruptible power systems. The software provides enhanced UPS monitoring and unattended system shutdown features for Windows 9x and Windows NT/2000. The software furnishes a complete record of critical power events and UPS activity on an event log, helping you spot, diagnose, and react more effectively to problems. On-line manuals include easy-to-follow installation and operating instructions in either Adobe Acrobat or ASCII formats.
1.5K unit Linear/1 UPS
1.5K unit
front view
1. 5K unit Linear/1 UPS
1. 5K unit
rear view
3, 4, 5K unit Linear/1 UPS
3, 4, 5K unit
face plate/controls
3, 4, 5K unit Linear/1 UPS
3, 4, 5K unit
front angle view
3, 4, 5K unit Linear/1 UPS
3, 4, 5K unit
angle view, with battery cabinet
8K unit Linear/1 UPS
8K unit
front angle view
8K unit Linear/1 UPS
8K unit
open case
Linear/1 family Linear/1 UPS
Linear/1 family
front/top angle view

Plug Types

Many people in the medical arena feel that with a generator in the line as an emergency backup for when the electric power grid goes down that there is no need for UPS back up power or line conditioning. This is not true. What most people forget or just simply do not know are issues that should be of concern which I have listed herein below.

  • A generator will kick in providing power only when the power grid goes down and stops providing electrical power.
    • The generator will take 10 to 20 seconds to start in which time the critical medical equipment will in fact stop operating unless it has an internal backup power supply which is usually a small supply meant to keep the medical equipment in question going during this short 10 to 20 seconds or in the case that the generator for some reason does not start will help provide an orderly shutdown of the critical equipment. This small internal backup is also very dependent on the need for good fresh batteries. One more thing that one needs to keep in mind is that after the generator starts there is a transfer switch which transfers your facility from the power grid to your generator. This transfer switch will always create a spike and like a lightning strike no one can predict where it will strike and many times will strike the critical medical equipment causing extensive damage at the most inopportune time. An additional item to consider with a generator is the “line noise” created by the armature/commutator when generating electricity. This noise can be very detrimental to sensitive critical medical equipment internal components such as circuit boards.
      • With the Linear/1 UPS in the system the backup time is increased to 10 minutes or more depending on the load and the size of the UPS. The Linear/1 UPS is also a power conditioner that will filter out the spike created by the transfer switch, and the noise created by the generating of the electric power.
    • One major element to keep in mind with an emergency generator in the line is that the generator will start up providing electric power only after power is lost from the power grid which is the only single purpose a generator serves.
      • With the Linear/1 UPS in the line monitoring the generator and the power grid continuously correcting power infractions as needed. One infraction is “sagging power” more commonly known to the general public as a “brown out”. During these times of sagging power which a generator does not address, your critical medical equipment is struggling to operate on minimal input power which is creating stress on circuit boards eventually causing circuit board components to blow destroying the circuit board shutting down your equipment which could happen at a critical moment of operation.

Everyone that works in the medical arena on patients with sensitive critical equipment should note the justification for placing the Linear/1 UPS in the line with a generator. If you do not have a generator Accratech has battery cabinets available that when connected to the UPS will provide additional run time fulfilling your backup time requirements.

The Linear/1 UPS certified UL 60601-1, 3rd Edition, the Last word in perfect power providing safe conditioned, continuous electrical power for your professional medical team using sensitive critical medical equipment on patients that are counting on a perfect procedural outcome manufactured by Accratech, Inc.

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