How the Schneider ATV630 Cuts Pump & Fan Energy by 20–50%

How the Schneider ATV630 Cuts Pump & Fan Energy by 20–50%

9 June 2026 · 13 min read · Trans-Digi Global

The short answer: a centrifugal pump or fan’s power draw falls roughly with the cube of its speed, so a drive that runs it 20% slower can cut its input power by close to half. The Schneider Altivar Process ATV630 variable speed drive does this by matching motor speed to the real flow or pressure demand instead of running flat out and throttling. On variable-duty pumps and fans, savings in the 20–50% range are well documented: the UK Carbon Trust puts a 20% speed reduction at up to 50% less energy, and Hydraulic Institute, Europump and US Department of Energy guidance reports 30–50% savings in many pump installations. The exact figure on your site depends on the load profile and how much static head the system has, and this guide shows how to estimate it before you buy.

In this article

• Why slowing a pump or fan saves so much: the affinity laws
• What energy savings can I expect from adding a VFD to a booster pump?
• ATV630 features that matter for pumps and fans
• Sizing and selection checklist
• Installation and commissioning: step by step
• From our projects: what pump and fan drive replacements look like in practice
• Singapore context
• Frequently asked questions
• Get the right ATV630 for your pump or fan
• Sources

Pumps are a large share of motor energy use. Guidance from the Hydraulic Institute, Europump and the US DOE states that pumping systems account for nearly 20% of the world’s energy used by electric motors. In a Singapore building, most of that load sits in chilled-water pumps, condenser-water pumps, cooling-tower fans, air-handling units and carpark ventilation fans. Those are the duties this article covers.

Why slowing a pump or fan saves so much: the affinity laws

Centrifugal pumps and fans are variable-torque loads. Their behaviour with speed is described by the affinity laws:

• Flow is proportional to speed (90% speed ≈ 90% flow).
• Pressure or head is proportional to speed squared (90% speed ≈ 81% head).
• Shaft power is proportional to speed cubed (90% speed ≈ 73% power).

That cube relationship is where the savings come from. A fixed-speed pump controlled by a throttling valve, or a fan controlled by a damper, keeps the motor at full speed and burns off the surplus energy across the valve or damper. A VSD such as the ATV630 removes the surplus at source by lowering the speed. The DOE pumping sourcebook calls pump speed adjustment “the most efficient means of controlling pump flow”, and notes that most of the savings come from cutting friction, throttling and bypass losses.

Worked example: a 15 kW pump at reduced speed

The table below applies the ideal affinity laws to a pump drawing 15 kW at full speed. It is an illustration, not a site measurement: it assumes a friction-dominated system with no static head and ignores the small losses in the drive and motor.

Few plants run at one speed all day, so a duty profile gives a more realistic view. Suppose the same pump spends 30% of its hours at full speed, 40% at 80% speed and 30% at 60% speed. Its average power is (0.3 × 100%) + (0.4 × 51.2%) + (0.3 × 21.6%) ≈ 57% of full-speed power, a saving of about 43% compared with running at full speed all the time. That is why 20–50% is a sensible planning range for variable-duty pumps and fans. A system that seldom slows down will sit at the bottom of the range or below it. A system that spends long hours at low demand can do better.

When the 20–50% range applies, and when it doesn’t

Every reputable source attaches conditions to these numbers, and you should check them before signing off a business case:

• High static head reduces the savings. When a pump has to lift water to a height or overcome a fixed back-pressure before any flow starts (boiler feed and some booster duties are examples), flow no longer falls in proportion to speed. The Hydraulic Institute and Europump guide warns that using the affinity laws to calculate savings in such systems “can also lead to major errors”. The Carbon Trust says the benefits will be reduced on high-static-head systems.
• The biggest savings come from variable demand. The cube law rewards time spent at reduced speed. The Carbon Trust advises reviewing the case for a VSD where the load stays high, for example when a motor’s maximum load is around 90%.
• Constant-torque loads follow a different rule. Conveyors and many compressors draw power in direct proportion to speed, so halving the speed roughly halves the power. That is still useful, but it is not the cube-law saving.
• There is a practical minimum speed. The Carbon Trust notes that a VSD-controlled fan will normally slow to about 20–30% of speed, not to zero. Pumps also need enough speed to keep producing useful head.
• Fix the system first. The Carbon Trust recommends removing waste before sizing a drive: isolate redundant pipework or ducting, repair leaks, remove unused dampers and valves, and check whether the motor itself is oversized.

What energy savings can I expect from adding a VFD to a booster pump?

The short answer: usually less than on a circulating pump, but still worthwhile where demand varies through the day. A domestic water booster set has to hold a fixed delivery pressure at the top of its zone, so much of its head is static head that does not fall when the pump slows down. Treat the 20–50% range above as an upper bound for a booster, not a forecast. The Hydraulic Institute and Europump guide Variable Speed Pumping warns that using the affinity laws to calculate savings in systems with static head “can also lead to major errors”, so the figure for your building has to come from the system curve and a measured demand profile.

A booster set (also called a pressure booster set) is a packaged group of pumps, a controller and a pressure vessel that raises mains or tank water to the pressure each floor needs. In high-rise buildings, the CIBSE Journal guide to pumping wholesome water notes that supply is typically zoned, with a separate pump set and riser for each pressure zone. Where a drive does save energy on a booster, the saving comes from these sources:

Variable speed sets also bring benefits beyond the kWh figure. CIBSE notes that soft start and stop reduce hydraulic and electrical stresses, and that expansion vessels fitted to sets with variable speed drives are typically smaller.

How to estimate the saving for your building

1. Find the static share of the head: the lift from the break tank or suction to the highest outlet, plus the minimum pressure needed there, compared with the total design head. The higher the static share, the smaller the saving.
2. Check how the set is controlled today: fixed-speed pumps cycling on pressure switches, throttled valves or a bypass all leave more room for savings than a set that already runs at variable speed.
3. Log the demand profile: flow or pump power over a representative week. The savings come from the hours spent below design demand.
4. Use the system curve, not the cube law: plot the system curve against the pump curves at reduced speed, as the Hydraulic Institute guide recommends for systems with static head.
5. Measure after commissioning: compare the drive’s kWh counters with the baseline over a comparable period.

Booster, transfer and pressurisation pumps are one of the pump and water system applications we support, with closed-loop pressure control, multi-pump cascade and alternation, sleep and wake operation and dry-run protection. Our published case studies do not report a measured booster-pump saving, so we do not quote one here. For pump-specific drives, see the Himel Smart Pump Series.

ATV630 features that matter for pumps and fans

The ATV630 belongs to Schneider Electric’s Altivar Process ATV600 family, which Schneider describes as drives “focused on fluid management and processing and energy saving”. The points below come from Schneider’s ATV600 catalogue and programming manual.

Ratings

• Wall-mounting IP21/UL Type 1 versions from 0.75 kW to 315 kW at 380–480 V three-phase, and 0.75–75 kW at 200–240 V. IP55 versions are available up to 90 kW.
• Normal duty (up to 110% overload) for pumps and fans, and heavy duty (up to 150% overload) for more demanding starts.
• Control of asynchronous (induction) motors as well as permanent-magnet and synchronous reluctance motors.

Energy functions

• Built-in power measurement (Schneider states it is accurate to within 5%) with kWh counters and energy dashboards. Performance can be shown in working units such as kWh/m³.
• An Energy Saving screen that compares cost, energy and CO₂ against a reference power entered for the system without a drive. It is useful for checking savings after commissioning.
• “Stop & go”, which Schneider says can cut the drive’s own consumption by up to 30% during system stop phases by switching off functions such as the power section and fans. The motor restarts in under 2 seconds.
• Sleep/wake-up, so the pump stops when demand drops to nothing instead of idling against a closed system.
• Friction loss compensation, which lowers the pressure setpoint at low flow so the pump does not hold more head than the system needs.

Pump control and protection functions

• Booster and level control with multi-pump staging and duty sharing, plus jockey-pump and priming-pump management.
• Pump curve integration and sensorless flow estimation, which keep the pump near its best operating point without adding a flow meter.
• Pipe fill, which helps prevent water hammer when an empty system is filled.
• Dry-run, low-flow, anti-jam, inlet/outlet pressure and pump-cycle monitoring to protect the pump as well as the motor.
• For fans: a dedicated fan dashboard, PID control, jump frequencies to skip resonant speeds, and catch-on-the-fly restart.

Integration and power quality

• Embedded Modbus TCP and Modbus serial link with a built-in web server. Option modules cover EtherNet/IP, PROFINET, CANopen, PROFIBUS DP V1, DeviceNet and BACnet MS/TP, which suits building-management systems.
• Harmonics: the standard drive is specified at THDi ≤ 48% at 80–100% load, using an embedded DC choke. Passive filter options are listed for THDi below 10% or below 5% where a project sets a tighter limit.

For the connectivity and protection side of the drive, see our companion article on ATV630 smart motor control. For lighter HVAC duties, read about energy optimisation with the ATV212 HVAC drive.

Sizing and selection checklist

Before requesting an ATV630 quotation, have these points ready. They decide whether the energy case holds and which reference to order:

• Motor nameplate: rated kW, voltage, full-load current, speed and motor type (induction, permanent magnet or synchronous reluctance).
• Duty rating: normal duty (110% overload) is typical for centrifugal pumps and fans. Choose heavy duty (150%) if the load is hard to start.
• Load profile: hours per year at each flow or speed band. Without it, any savings figure is a guess.
• Static head: how much of the total head is fixed lift or back-pressure. A high share means smaller savings.
• Control signal: pressure, flow, level or temperature sensor, BMS speed reference, or fieldbus. Confirm which protocol the BMS or PLC uses.
• Harmonic limit: check the project specification for a THDi or IEEE 519 requirement and allow for filters if needed.
• Enclosure and environment: IP21 inside a panel or IP55 wall-mounted, ambient temperature, and space for ventilation.
• Existing equipment: motor age and insulation condition, cable length and size, and whether bypass or fire-mode operation is required.

Installation and commissioning: step by step

1. Survey the system and remove obvious waste first: open throttled valves, remove redundant dampers and repair leaks.
2. Record a baseline. Log the existing motor’s kW or current and running hours for a representative period so savings can be measured later.
3. Confirm the drive reference, duty rating, enclosure, filters and communication option against the checklist above.
4. Install to the manufacturer’s instructions, with correct cable sizing, earthing and EMC practice and enough clearance for cooling.
5. Enter the motor data and run auto-tuning, then set acceleration and deceleration ramps and low and high speed limits.
6. Configure the application: PID setpoint, sleep/wake-up, multi-pump staging, pump curve and protection functions such as dry-run and low-flow monitoring, or fan jump frequencies.
7. Test the control interface with the BMS or PLC: start/stop, speed reference, feedback and alarms.
8. Verify the harmonic level where the specification requires it, and confirm fire-mode or bypass behaviour where it applies.
9. Measure kWh after commissioning over a comparable period and compare it with the baseline. The drive’s own energy counters make this straightforward.
10. Hand over with as-built parameter records so the settings can be restored after maintenance.

From our projects: what pump and fan drive replacements look like in practice

Our published project references cover the same duties the ATV630 is built for. Most of them use Himel HAVSP Smart Pump Series drives rather than the ATV630, but they show what decides a successful pump or fan VSD project in Singapore buildings:

• Multiple duties on one site. At Seletar Mall, we supplied 33 VSDs from 0.75 kW to 15 kW to replace the existing drives on cooling towers, chilled-water pumps, condenser-water pumps and basement carpark fans, then tested and commissioned them.
• Older motors stay in service. At Singapore EXPO, the new 7.5 kW and 37 kW drives for cooling towers, chilled-water and condenser-water pumps had to run motors that had been in service for more than ten years. Compatibility with existing motors is often the main technical issue in a retrofit.
• Footprint and cabling. At Tanah Merah Ferry Terminal, a compact drive footprint simplified replacing the existing chilled-water and condenser-water pump drives, and the new layout helped the project team reduce cabling costs.
• Harmonic limits are checked drive by drive. At the ST Aerospace Aviation Centre, the specification required less than 35% THDi, and we measured the harmonic level of every installed drive before handover. For projects with a harmonic specification, the ATV630 offers passive filter options rated for THDi below 10% or below 5%, so the right option can be chosen at the selection stage.
• Energy consultants set the performance requirements. At Silicon Box, the drives for carpark exhaust, chilled-water, condenser-water and cooling-tower systems had to meet requirements set by the project’s energy consultants.

None of these published case studies reports a measured kWh saving, so we do not quote one here. Savings depend on the site, which is why the baseline and post-commissioning measurement steps above matter. See all our project success stories.

Singapore context

In Singapore, manufacturing companies may also be able to get co-funding through NEA’s Energy Efficiency Fund (E2F). In 2023, NEA raised support for pre-approved energy-efficient technologies to 70%. Check current eligibility and the list of supported technologies directly with NEA before planning a project around a grant.

Related reading: VFD sizing for pumps: a step-by-step guide.

Frequently asked questions

How much energy can the ATV630 save on a pump or fan?

On variable-duty centrifugal pumps and fans, 20–50% is a realistic planning range. A 20% speed reduction can cut input power by close to half, according to the affinity laws and Carbon Trust guidance. The actual saving depends on the load profile and how much static head the system has.

Where does a VSD save the most energy?

On pumps and fans whose demand varies, especially where flow is currently controlled by throttling valves, bypass lines or dampers. Slowing the motor removes that wasted energy at source.

Why are savings lower on systems with high static head?

Static head is fixed pressure the pump must overcome before any flow starts. In those systems, flow does not fall in proportion to speed, so the ideal cube-law saving is not reached. Industry guidance warns that applying the affinity laws directly to such systems can lead to major errors.

Can I use a VSD on a water booster set?

Yes. The drive holds a constant delivery pressure by PID control from a pressure transmitter, stages the duty and assist pumps as demand changes, and stops the pumps when there is no demand. The ATV630 includes booster control with multi-pump staging and sleep/wake-up. Because a booster works against a large static head, expect smaller savings than on a circulating pump, and estimate them from the system curve.

How does a VSD reduce pump energy costs?

By slowing the pump to the flow or pressure actually needed, instead of throttling, bypassing or cycling it. A centrifugal pump’s power falls roughly with the cube of its speed, so a 20% speed reduction can nearly halve its input power, and the Hydraulic Institute and Europump guide reports savings of 30–50% in many rotodynamic pump installations. A drive also corrects oversizing, which the same guide estimates affects 75% of pump systems, and slower running reduces bearing and seal wear.

Can the ATV630 connect to a building management system?

Yes. It has embedded Modbus TCP and Modbus serial communication, and option modules add BACnet MS/TP, EtherNet/IP, PROFINET, CANopen, PROFIBUS DP V1 and DeviceNet.

How do I check the savings after installation?

Record the motor’s energy use before the change, then use the ATV630’s built-in power measurement and kWh counters, which Schneider states are accurate to within 5%, to compare a similar period afterwards. Its Energy Saving screen can also compare consumption with the original system.

Get the right ATV630 for your pump or fan

Trans-Digi Global supplies the Schneider Altivar Process ATV630 and the wider Schneider Electric range in Singapore, alongside our other variable speed drives. We also provide testing, commissioning and replacement services for pump and HVAC applications. Send us the motor rating, voltage, phase, quantity and application through our contact page. We will confirm the exact model, check stock and send a quotation the same business day.

Sources

• Schneider Electric, Altivar Process ATV600 Variable Speed Drives catalogue (DIA2ED2140502EN, August 2021)
• Schneider Electric, Altivar Process ATV600 Programming Manual (EAV64318)
• Hydraulic Institute, Europump & US DOE, Variable Speed Pumping: A Guide to Successful Applications, Executive Summary
• US DOE & Hydraulic Institute, Improving Pumping System Performance: A Sourcebook for Industry, 2nd ed. (2006)
• Carbon Trust, Variable speed drives technology guide (CTG006, 2007)
• CIBSE Journal, CPD Module 153: Pumping wholesome water in buildings (October 2019)
• NEA, Enhancements to the Energy Efficiency Fund (E2F), March 2023
• Trans-Digi Global project case studies: Seletar Mall, Singapore EXPO, Tanah Merah Ferry Terminal, ST Aerospace Aviation Centre, Silicon Box

Figures are taken from the publications listed. Drive ratings and functions vary by reference and firmware, so confirm them against the current Schneider Electric documentation for your exact part number.