GlobalSpec has asked its users about the latest design trends and features related to Three Phase Uninterruptible Power Supplies (UPS). They have also shared their product applications and tips on how to buy and use these products.
See the entire survey


Q:
Do you have any advice for people relative to buying or using three phase uninterruptible power supplies?
14 answers
Answers:
When you buy the three phase UPS, check the UPS specification and whether your load is considered inductive, capacitive or resistive. Efficiency of 50% Load and 100% load of UPS Protection features inbuilt in system. Appropriate rating gives system to calculate load and finalize.
~SURESH GHOBLE, EMI/EMC Design Engineer, PUNE, INDIA
Look for the highest possible reliability. Everything else is secondary. Although more expensive and less efficient, soma applications deserve a UPS with an output isolation transformer.
~Selim A, Engineering Consultant, Istanbul, Türkiye
Full commissioning effort with power quality measurement is a must when starting a UPS. Manufacturer's claimed performance standards should always be validated, especially for batteries.
~Facilities Manager, Las Vegas, NV
Load study is very important 1. Harmonic details 2. K factor 3. Type of load like heater, compressive, inductive, compressive 4. Peak current 5. Rated load 6.Initial torque load
~VIBHAKAR L PATEL P, Soltion provider cum marketing, RAJKOT, India
Advise them to measure the load and see which type of load there is before they do any buying. Ex: How big is the capacitive or inductive load and the total load in kw.
~Gunnar H, Technical Support, Oslo, Norway
Look to long term usage, high ambient temperature loading factors & over-specify KVA to allow for missing loads (there are always missed circuits).
~Roger W, Estimating Procurement Manager, Overland Park, KS
Make sure you have a good support contract and make sure the UPS is sized correctly for the load, not too big or too small.
~Engineer, Sault Ste. Marie, Canada
Understand redundancy features and implications research batteries - life versus cost, operating temp, recharge time.
~Bruce T, Engineering Consultant, Perth, Australia
Manage power distribution so phase loads don't shift when restarting multiple power supply computer systems.
~Jere R, Network Manager, Jeffersonville, KY
They should thoroughly check specifications of UPS system with the battery offered.
~Sudhir KULKARNI, Area Manger Marketing/Business development, Mumbai, India
Yes , make sure when upscaling a server park, to upscale your UPS as well!
~Didier S, Design Engineer, Veldhoven, The Netherlands
Check & review after sales support & maintenance contract
~Lazaro G, Technical Staff, Manila, Philippines
Buy high frequency design only.
~S DATTA, Marketing/Sales, New Delhi, India
May soon test as a solution.
~Tomasz K, General Management, Cracow, Poland

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Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of three phase uninterruptible power supplies?
13 answers
Answers:
COMPRESSOR has very high initial torque almost 10 times than rated & hence during battery operation, UPS will get tripped. So capacity of UPS will require very high capacity. Heater load will be beneficial, as it will improve your power factor. UPS should at least give you 150% load capacity for 10 seconds, so that for any initial torque it does not get tripped . It must have an isolation transformer at output side else IGBT will be blown off frequently. For industrial usage, SCR based rectifier will be highly reliable compared to IGBT based rectifier. As IGBT is a highly switchable & sensitive device & hence tends to fail frequently.
~VIBHAKAR L PATEL P, Soltion provider cum marketing, RAJKOT, India
While selecting the UPS they must be aware about type of load they are going to put on prospective UPS, whether it is inductive load or low inrush current load. If they are buying for inductive load they should prefer isolation transformer technology, or for it load they can opt high frequency technology.
~RAKESH B, Marketing/Sales, DELHI, INDIA
When supplying motor loads make sure your UPS is able to handle back feed from load. Make sure you have a solid neutral, both at by pass as well as normal operation.
~Selim A, Engineering Consultant, Istanbul, Türkiye
Following: 1) Check KVA/KW capacity at Ambient Temperature .i.e 40 Deg C. 2) Check Battery sizing calculation. This is a must to get proper backup and check economics.
~Sudhir KULKARNI, Area Manger Marketing/Business development, Mumbai, India
UPS must be an On-line (Double-Conversion) type. Protection as follows: Lightning, Over Voltage, Power Failure, Short Circuit, Surge
~Gunnar H, Technical Support, Oslo, Norway
For example if you calculate that you need a 37.5 KVA UPS, consider purchasing a 50 KVA, the cost is neg. & ROI is more palatable.
~Roger W, Estimating Procurement Manager, Overland Park, KS
Ensure that a UPS (10-yrs. min.) experienced, licensed professional engineer are part of the user's team.
~Ralph J, P.E., Chief, Senior Electrical Power Engineer, Sterling, VA
Ensure it meets all regulatory requirements (back feed protection, warning labels etc).
~Bruce T, Engineering Consultant, Perth, Australia
Check UPS loading relative to battery size, request for battery sizing detail
~Lazaro G, Technical Staff, Manila, Philippines
Online UPS is a must when choosing a solution for critical applications.
~Facilities Manager, Las Vegas, NV
The three phase inverters should be able convert back to single phase.
~Jerry G Sales and installation, Marketing/Sales, Muskogee, Muskogee
Actual load calculate on 1 to 0.7PF.
~SURESH GHOBLE, EMI/EMC Design Engineer, PUNE, INDIA
Buy a UPS which gives input pf 099.
~S DATTA, Marketing/Sales, New Delhi, India

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