This article covers protecting Thunder Laser Nova series machines with Uninterruptible Power Supplies.


This presents some complexities as the chiller needs to be in play. If it's an active chiller it will have a capacitor-start compressor. This may be a consideration when selecting the UPS.


The power requirements for the laser machine and the chiller must be taken into account as well as anything else you may want to protect. And be sure to add a minimum of 10% headroom (20% is better). 


You can find the power requirements for the Nova series machines here:

Thunder Laser Main Power Requirements


Once you get the total wattage value and calculate the safety factor you can decide which type of UPS is best for you. 


There are three basic types of UPS configurations: Offline UPS, Line-interactive, and Online UPS:


Offline UPS—Entry-level Power Protection

In an off-line ("standby") UPS system, the load is powered directly by the input power and the backup power will only be delivered if the power fails.


Benefits

  • Efficiency (The charger is not constantly on).

  • User-friendly

  • Affordable price.

Limitations

  • Uses battery during brownouts, limited or no protection against power irregularities.

  • The load is continuously exposed to spikes, transients, and any other anomalies coming down the power line.

  • Finite transfer time from mains power to inverter when the mains power supply fails.


Offline UPS Working Principle

Line-interactive UPS—Intermediate Level Power Protection

A line-interactive UPS maintains the inverter in-line and redirects the battery's DC current path from the normal charging mode to supplying current when power is lost.


Benefits

  • High-reliability.

  • High-efficiency.

  • Reasonable voltage conditioning.

  • Lower electricity consumption.

  • Lower component count.

  • Lower operating temperatures.

Limitations

  • Impractical over 5kVA.

  • Not protect against all forms of power irregularities.

  • Do not provide power-factor correction or frequency regulation.

  • Require frequent battery use in areas of extreme voltage distortion.



Line-interactive UPS Working Principle

Online UPS—The Ultimate Power Protection

An online UPS uses a "double conversion" method of accepting AC input, rectifying to DC for passing through the rechargeable battery (or battery strings), then inverting back to 120 V/230 V AC for powering the protected equipment.


Benefits

  • Better voltage regulation.

  • Conversion time from DC to AC is negligible with no gaps in coverage.

  • No fluctuations in the voltage, indicating stable voltage quality.

  • The quality of the load voltage is free from distortion.

  • Near ideal electrical output, highest protection against all power irregularities.

Limitations

  • Complex designs requiring a large heat sink.
  • Higher power dissipation.

  • The overall efficiency of UPS is reduced (The inverter is always on).

  • The wattage of the rectifier is increased (It has to supply power to the inverter as well as charge the battery).

  • Costlier than other UPS systems.


Online UPS Working Principle


Here are some additional considerations: 


Surge/Noise Protection

All the three UPS systems possess surge suppression and line noise filtering functions to shield the equipment from damage caused by lightning, surges, and electromagnetic (EMI/RFI) line noise. Particularly, the online UPS system offers superior protection on account of the double-conversion operation that isolates equipment from problems on the AC line.


Transfer Time to Battery

During an outage, a 2 to 10 milliseconds can be expected in offline/standby UPS systems. Line-interactive UPS systems typically transfer in 2 to 4 milliseconds, faster enough to keep all but a small percentage of the most power-sensitive equipment operating without interruption. 

The online UPS system does not have a transfer time, because the inverter is already supplying the connected equipment load when an outage occurs.


Voltage Regulation

Line-interactive UPS systems use automatic voltage regulation (AVR) to correct abnormal voltages without switching to battery. When voltage crosses a preset low or high threshold value, this type of UPS will detect and use transformers to boost or lower the voltage by a set amount to return it to the acceptable range. 


Online UPS systems adopt a more precise method of voltage regulation: continuous "double-conversion" operation, isolating connected equipment from problems on the AC line, including blackouts, brownouts, over-voltages, harmonic distortion, electrical impulses, and frequency variations. 


When not operating from the battery, line-interactive UPS systems typically regulate output within ±8-15% of the nominal voltage (e.g. 120, 208, 230, or 240 volts), whereas online UPS systems typically regulate voltage within ±2-3%.