Variable Frequency Drives and Soft Starters: Procurement Guide

Define the operating objective

A variable frequency drive (VFD, also called a variable speed drive) is used where motor speed control is required. A soft starter is commonly selected to manage the starting and stopping process. They are not interchangeable simply because both are associated with a motor of the same power.

Use the complete motor and supply data

Provide motor voltage, rated current, power and frequency, along with supply phases and voltage. Describe the driven equipment: a pump, fan and conveyor may have different starting and overload requirements. Record ambient conditions, enclosure needs and any project derating requirements.

List the peripherals

A complete order may include a keypad, communication option, filter, reactor, braking component or bypass arrangement. Identify the exact accessories specified by the designer. Do not assume a photograph of a product family represents the full supply scope of a particular SKU.

Check replacement compatibility

For an installed system, record parameter backups, control interfaces and communication protocols before selecting an alternative. A replacement drive can require changes to commissioning and controls even when the voltage and power match. The machine or process owner should approve the technical change.

RFQ information

Send the existing reference, motor nameplate, application, supply data, accessory list, quantity and destination. Separate a like-for-like spare enquiry from an upgrade request. This lets the quotation address both the hardware and any unresolved compatibility questions.

Explore catalog references

Examples for product research; suitability and availability must be confirmed for your project.

• Schneider Electric ATS480C41Y — Soft starter, Altistart 480, 410A, 208 to 690V AC, control supply 110 to 230V AC
• Schneider Electric ATV310HU22N4E — variable speed drive, Easy Altivar 310, heavy duty, 2.2kW, 3hp, 380 to 460V, without EMC
• Schneider Electric ATV930D90N4 — variable speed drive, Altivar Process ATV900, ATV930, 90kW, 400 to 480V, with braking unit, IP21

Manufacturer references

• Schneider Electric documentation: ATS480C41Y
• Schneider Electric documentation: ATV310HU22N4E
• Schneider Electric documentation: ATV930D90N4

These AI-assisted purchasing guides use manufacturer references and catalog data. They are not installation instructions or a substitute for project-specific engineering approval.