Choosing a VFD for a water pump is not only about matching motor power. The inverter becomes part of the water system, so selection should also consider voltage, motor type, pressure control, sensor compatibility, communication, protection, installation and pump quantity.

AUSENIST develops pump-specific inverter solutions for different pump brands and types, including cabinet-mounted and pump-mounted configurations, PMSM and induction motors, constant-pressure systems and multi-pump applications.

1. Start with the Pump Application

First define what the pump is doing.

A VFD for a domestic booster system may need different functions from one used in irrigation, industrial boosting, sewage treatment or a multi-pump building water system.

AUSENIST pump inverters are designed for broad pump compatibility, helping distributors and OEM manufacturers use one control platform across different pump products.

2. Confirm Voltage Before Selecting the VFD

Voltage is one of the first parameters to confirm.

AUSENIST pump inverter solutions support common 220V and 380V requirements, while 440V and 460V versions can also be customized for suitable projects.

Do not choose an inverter by motor power alone. Confirm input voltage, motor rated voltage, motor power, supply phase and destination market before ordering. If the voltage is unusual, confirm customization before the pump design is finalized.

3. Match the Inverter to Motor Power

The correct model also depends on the inverter series.

The AUSENIST 620 series covers 0.75kW to 7.5kW, while the 820 series covers 0.75kW to 22kW.

The 620 series is suitable for lower-power intelligent pump systems where communication and multi-pump control are important. The 820 series provides a wider range for pump lineups extending above 7.5kW.

4. Identify PMSM or Induction Motor

Traditional pumps commonly use asynchronous induction motors, while many newer high-efficiency pumps use permanent magnet synchronous motors, or PMSM.

AUSENIST 620 and 820 pump inverter platforms support both PMSM and induction motors.

This two-in-one compatibility can simplify product planning because one inverter platform can serve different motor technologies.

Before ordering, confirm motor type, rated voltage, power, current and speed. Correct parameters should be configured rather than assuming one setup fits every motor.

5. Decide Whether Constant-Pressure Control Is Required

Many pump applications need stable water pressure while demand changes.

The AUSENIST 620 platform is designed for constant-pressure water supply and uses PID control to adjust pump speed according to water demand.

Higher demand can increase pump speed. Lower demand can reduce speed. When there is little or no demand, intelligent sleep can stop unnecessary running, and the system can resume when pressure demand returns.

6. Check Sensor Compatibility

The pressure sensor is critical because the inverter needs reliable feedback to regulate pump speed.

AUSENIST pump inverter solutions are compatible with different sensor types, allowing the controller to be adapted to different pump-system designs.

Before production or installation, confirm sensor type, signal, pressure range, supply requirement and wiring method.

7. Determine Whether One Pump or Multiple Pumps Are Needed

A multi-pump system may require communication, pump sequencing, pressure coordination, standby logic and fault handling.

AUSENIST pump inverter solutions can support up to six pumps. The 620 platform uses a dual-master architecture with up to four auxiliary pumps.

Dual-Master Backup

If the active master has a communication fault, sensor problem or hardware failure, the standby master can automatically take over system control.

Automatic Failed-Pump Bypass

If an auxiliary pump fails, the system can skip the faulty pump and start the next available unit.

Timed Pump Rotation

If the same pump always starts first, its operating hours increase faster than the others. The 620 system supports automatic rotation, with an 8-hour default setting in the documented configuration, helping distribute operating time more evenly.

8. Check Communication Requirements

Communication should be considered before the model is finalized.

The AUSENIST 620 series uses dual RS485 interfaces across its full power range.

The 820 series uses a different configuration on some lower-power 220V models, while its 380V range uses dual RS485.

The best series therefore depends on both power and communication requirements. If several drives must communicate or future expansion is expected, communication should be part of the original selection criteria.

9. Choose Cabinet or Pump-Mounted Installation

AUSENIST pump inverter solutions can be installed in a cabinet, while compatible models can also use a backpack-style design mounted directly on the motor junction box.

The 620 platform uses an IP54 protected design and supports direct installation on compatible pump motors.

Consider available space, pump orientation, motor junction-box structure, environmental exposure and maintenance access before choosing the mounting method.

10. Check Pump-Specific Protection

A pump system needs protection against more than electrical faults.

AUSENIST pump inverter functions include water-shortage protection, pipe-burst shutdown, high and low water-pressure alarms, phase-loss protection, anti-freeze protection and anti-rust operation.

These functions matter because many pump problems come from hydraulic or environmental conditions. Water shortage may cause dry running. Abnormal pressure can indicate a pipe problem. Long idle periods can increase the risk of a pump becoming stuck.

11. Consider Soft Start and Water Hammer

Starting a pump directly can create high starting current and sudden pressure changes.

The AUSENIST 620 platform uses smooth starting to reduce motor starting impact and help reduce water-hammer effects in the pipe network.

12. Ask Whether Customization Is Needed

Standard models fit many projects, but OEM pump manufacturers often need a controller that matches their motor, pump design, brand and target market.

AUSENIST supports broad customization for pump inverter projects.

Customization can be discussed for voltage, product configuration, communication, control behavior and OEM integration. Current product materials also confirm that 440V and 460V versions can be customized and that customized solutions are available when a standard series does not fit.

A useful OEM request should include pump type, motor type and power, voltage, target market, sensor requirement, pump quantity, pressure-control requirement, communication requirement, installation method, protection functions, branding or private-label requirement and expected quantity.

13. 620 or 820: Simple Selection Logic

For many AUSENIST pump projects, start with two questions: required power and required communication.

Choose the 620 series when the motor is within 0.75kW to 7.5kW and strong multi-pump communication is important. Dual RS485 is provided across the series, and the platform supports dual-master multi-pump control.

Consider the 820 series when required power extends above 7.5kW and up to 22kW, or when its communication configuration fits the application.

Both platforms share important pump-oriented functions including IP54 protection, pump-mounted installation, PMSM and induction motor compatibility, multi-pump control, automatic restart, water-shortage protection, pipe-burst shutdown, anti-freeze protection and anti-rust functions.

Frequently Asked Questions

What information is needed to select a pump VFD?

Provide the application, motor power, voltage, motor type, pump quantity, pressure requirement, sensor information, communication requirement and installation method.

Can one inverter work with PMSM and induction motors?

Compatible AUSENIST 620 and 820 platforms support both motor types.

How many pumps can the system control?

Compatible AUSENIST systems can support up to six pumps.

Are 440V and 460V versions available?

Yes. AUSENIST can customize 440V and 460V configurations for suitable projects.

Can the inverter be customized for an OEM pump brand?

Yes. AUSENIST supports customized pump inverter solutions for OEM and project requirements.

Conclusion

The correct water pump VFD should be selected as part of the complete pumping system.

Voltage and power are only the beginning. Motor type, pressure control, sensor compatibility, pump quantity, communication, installation and protection functions can all change the correct choice.

AUSENIST supports standard and customized pump inverter solutions for different pump brands, PMSM and induction motors, constant-pressure systems, pump-mounted products and multi-pump applications.

Send the pump specification, motor data and application requirements to AUSENIST for a suitable inverter recommendation.

Website: www.ausenist.com