How Do I Select the Correct Line or Load Reactor for a PowerFlex 750 Drive?

Overview

When configuring a PowerFlex 750-Series drive with a line or load reactor, it is important to verify that the reactor is properly sized for the application.

This is especially important when configuring Heavy Duty PowerFlex 750 applications, because the appropriate output reactor may be different from the reactor normally associated with the drive horsepower.

The LVMCC configurator also does not perform all application checks associated with custom modifications. The person configuring the unit is responsible for verifying the application, component selection, quantities, and requirements associated with the modification. Reactor Selection LVMCC units 2…

How Should a Reactor Be Sized?

When manually selecting a line or load reactor, use the motor full-load amps (FLA) as the basis for selection.

The reactor's fundamental amp rating should be equal to or slightly greater than the total motor FLA.

Selection Rule

Reactor Fundamental Amp Rating ≥ Motor FLA

Do not select the reactor based solely on the drive's amp rating or horsepower.

Sizing the reactor to the drive ampere rating alone can result in an incorrectly sized reactor. Reactor Selection LVMCC units 2…

What Is Different About Heavy Duty Applications?

PowerFlex 750 drives can have different Normal Duty and Heavy Duty ratings.

When a drive is applied at its Heavy Duty rating, the appropriate output reactor may be different from the reactor normally associated with that horsepower.

The PowerFlex 750 Technical Data should be used to verify the appropriate reactor selection for the specific application. The presentation specifically identifies instances where a different reactor should be selected for a Heavy Duty PowerFlex 750 application. Reactor Selection LVMCC units 2…

For example, the presentation shows 480V applications where the recommended output reactor changes between Normal Duty and Heavy Duty operation.

The important point is:

Do not assume that the reactor associated with the drive horsepower is automatically correct for a Heavy Duty application.

Verify the motor FLA and the reactor's fundamental amp rating.

Selecting Reactors in PowerControl Builder

When configuring a PowerFlex 750 VFD unit as Configured-to-Order (CTO), PowerControl Builder determines the reactor based on horsepower and how the reactor will be used.

PowerControl Builder allows one reactor to be selected through CTO:

14RLX – Line (Input) Reactor

14RXL – Load (Output) Reactor

If only one reactor is required, select the appropriate input or output reactor through the normal CTO configuration. Reactor Selection LVMCC units 2…

What If Both a Line and Load Reactor Are Required?

PowerControl Builder only allows one reactor to be selected through the CTO configuration.

If the application requires both a line reactor and a load reactor, the recommendation provided in the presentation is to select the output reactor through CTO.

The additional reactor can then be handled through the appropriate engineered/custom modification process. Reactor Selection LVMCC units 2…

Engineered-to-Order (ETO) Reactor Selection

When configuring a reactor through Engineered-to-Order (ETO), the reactor must be manually selected for the application.

Verify:

Motor FLA
Reactor fundamental amp rating
Line/input versus load/output application
Normal Duty versus Heavy Duty operation
Required quantity of reactors
Available MCC space
Wiring and accessibility requirements
Heat contribution

The configurator should not be relied upon to perform all of these checks for custom modifications. Additional assistance may be required from the appropriate Rockwell Automation or distributor resource depending on the application. Reactor Selection LVMCC units 2…

Reactor Selection Process

Use the following process when selecting a reactor for a PowerFlex 750-Series drive:

Determine the motor FLA.
Determine whether a line/input reactor or load/output reactor is required.
Determine whether the drive is being applied at its Normal Duty or Heavy Duty rating.
Use the PowerFlex 750-Series Technical Data to verify the applicable reactor information.
Select a reactor with a fundamental amp rating equal to or slightly greater than the motor FLA.
If one reactor is required, select the appropriate reactor through CTO when available.
If both input and output reactors are required, select the output reactor through CTO and handle the additional reactor through the appropriate engineered/custom modification process.
Verify space, wiring, accessibility, and heat requirements when adding custom components.

Important

Do not select a reactor based solely on drive horsepower.

This is particularly important for PowerFlex 750 Heavy Duty applications.

The motor's actual FLA and the reactor's fundamental amp rating should be used when manually selecting the reactor. The presentation warns that sizing reactors to drive ampere ratings alone may result in an incorrectly sized reactor. Reactor Selection LVMCC units 2…

Also remember that custom modifications require additional application review because the configurator does not perform most of these checks automatically. Reactor Selection LVMCC units 2…

Supporting Documentation

VFD Units with Line and Load Reactors

[LINK: VFD Units with Line and Load Reactors PowerPoint Presentation]

Use this presentation for examples of Heavy Duty PowerFlex 750 output reactor selection, available LVMCC CMOD selections, and CTO/ETO configuration guidance. The original presentation is a September 2019 SEMCC Cadence Call covering VFD units with line and load reactors. Reactor Selection LVMCC units 2…

PowerFlex 750-Series AC Drives Technical Data – 750-TD001

[LINK: PowerFlex 750-Series Technical Data – 750-TD001]

Use the Technical Data publication to verify the applicable PowerFlex 750 drive and reactor selection information.