Critical Power Supplies - Facebook-double Critical Power Supplies - Twitter-double Critical Power Supplies - Linkedin-double Critical Power Supplies - Google-plus-double Freephone 24 Hour: 0800 978 8988 Int: +44 (0)1844 340122

How Water Pumps Affect UPS Selection

Published by Lee Kelly on 04 March 2020

Water pumps can be a hard product to find a suitable UPS due to a couple of different reasons. Choosing the correct system is critical so that you don’t experience any downtime or even a UPS that won’t detect your load.Critical Power Supplies - Industrial water pumping solutions

High Inrush Current

One of the main issues with selecting the right UPS is a high inrush current or also known as a high startup current or full lock current. This is due to when a water pump is starting up it usually has a load of usually 6 - 10 times its nominal current (this can vary system to system), which could easily overwhelm your UPS system if you didn’t take this into consideration. These sorts of the motor are either on or off and are not like variable speed drives. Variable speed drives allow UPS Solutions to be sized closer to the nominal rating as the maximum power draw is significantly reduced.

Low Nominal Load and Periods of No Activity

UPS systems have a feature called deep discharge protection. This prevents any damage on the battery under no or very little load. This is important as UPS Solutions during start-up check the battery is healthy and a deep discharge causing the battery to be below the minimum voltage will cause the UPS to reject the switch on request.  Therefore, the load from your water pump could potentially be too low for your system which means when the pump isn’t running or is on the very low load ( below 10% of the UPS Rating ) your UPS will switch off at a set design programmed into the UPS to protect the batteries from deep discharge risk rather than providing battery backup until the batteries reach the low battery threshold.

Variable Speed Driver

Water pumps based on variable speed drives that can be programmed to have a soft start this means the load is switched on with a soft start. By programming the VSD Drive to start this way your pump can be supported on a UPS system that is smaller than a DOL would be as this is because a UPS system has a 3:1 crest factor this means you can size a slightly smaller UPS due to the programmability of the speed driver.

What Do I Need to Calculate a UPS runtimes With a Water Pump?

When you need to calculate a UPS runtime for your water pump you need the following;

  • Number of minutes at full load
  • Number of mins with little load
  • Number of minutes with no load
  • UPS inefficiencies
  • DC to AC losses in the electrical circuit

This information will you the total Amperage of Battery you need for the duration you are looking to cover. At this stage, it would also be good to understand if you are looking for a 5-year or 10-year design life battery.

Critical Power Supplies - NXE from Riello UPS

How can I make my UPS easy?

The following list is considered the best practice questions to consider when reviewing your UPS installation checklist.

  • Can I safely deliver the UPS to the point of installation on-site? What is the access route like, door width and any or number of steps etc? Can I safely deliver the UPS?
  • Voltage input and output
  • Frequency input and output.
  • Number of outgoing circuits
  • Type of input and output required sockets or hardwired?
  • Bypass installation
  • Remote monitoring via SNMP or BMS interface?
  • Frequency of input and output.
  • Will the load change in the future?
  • Do you need an IP20 rated UPS or would a higher rating be better?
  • Do you need a special finish or even a stainless steel finish?
  • What in-life management will you need? Annual maintenance checks.

These questions will help any power partner discuss, quote and install a solution that makes you happy on the first day of handover and 5-years in the future.

Make Sure You Get it Right First Time

Being able to spec your UPS for your water pump will mean that you aren’t left disappointed if your power goes out and your pump doesn’t stay online. Making sure that your system is fit for purpose and letting you relax is our job.

If you would like to learn more about water pumps and their effects on what UPS system you should use contact our team of experts on 0800 978 8988 or drop them an email here.