Grundfos Variable Frequency Drives (VFD)

Q: How do I choose the right VFD?

Size it on the motor, not the pump — give us the motor’s rated kW and full-load current from its nameplate, plus your supply voltage and phase and where the drive will be mounted so we can set the IP rating.

Q: Will it fit my existing pump?

In most cases yes — the CUE is an external drive, so it is matched to your existing motor’s kW and full-load current rather than to the pump itself, and it can be retrofitted to a pump already installed. Send us the motor nameplate details and we will confirm.

Q: What is the difference between CUE and MGE?

CUE is a separate drive mounted alongside the pump and suits retrofits, while MGE is a variable-speed motor built into a Grundfos E-pump from the factory.

Q: How much will it actually save?

The saving comes from matching speed to demand rather than throttling a valve. Because pump power falls roughly with the cube of speed, a modest reduction in flow cuts running cost substantially — the exact figure depends on your duty profile and operating hours, so we work it out from those.

Q: Does it give soft start?

Yes — ramping the motor up removes the mechanical shock on the pump, coupling and pipework and takes the start-current spike off your switchboard.

Q: Can it be mounted outside a switchboard?

Yes, if you specify an IP55 enclosure. IP20 and IP21 units are intended for mounting inside a cabinet.

Q: How do I get a price?

Send us the motor nameplate, your supply details and the mounting location, and we will quote the right CUE frame size and confirm lead time.

Variable frequency drives and variable speed motors for running pumps at the speed a system needs.

Categories: Centrifugal Pumps, Water Pumps

Applications: LSS, RAS, Water & Wastewater Treatment

Brand: Grundfos

Grundfos Variable Frequency Drives (VFD)

Product Information

Key Features

Grundfos CUE is an external frequency converter that works with a broad range of Grundfos pumps; the Grundfos MGE is the variable-speed motor built into Grundfos E-pumps
Covers motors from 0.55 to 250 kW (0.75 to 350 hp)
Single-phase 1 x 200–240 V and three-phase 3 x 200–240 V, 3 x 380–500 V, 3 x 525–600 V and 3 x 525–690 V supplies
IP20, IP21 or IP55 enclosures depending on size, so the drive can sit in a switchboard or out on the wall of a wet plant room
Matching pump speed to actual demand instead of throttling a valve delivers a large cut in running cost — pump power falls roughly with the cube of speed, so even a modest reduction in flow saves a disproportionate amount of energy
Gives you flow turndown across the whole operating range rather than one fixed duty, plus soft start, which takes the mechanical shock off the pump, coupling and pipework and removes the start-current spike from your switchboard
Drives asynchronous, permanent-magnet and synchronous reluctance motors, with Safe Torque Off available and sensor inputs for closed-loop control
Sizing: a VFD is selected on the motor it has to drive, not on the pump’s flow. Give us the motor’s rated kW and its full-load current from the nameplate, your supply voltage and phase, and where the drive will be mounted so we can set the IP rating. The datasheet we hold does not publish rated output current per model, so we confirm that against current Grundfos selection data before quoting.

Specifications

Specification	Detail
Product	Grundfos CUE external frequency converter. The Grundfos MGE is the variable-speed motor built into Grundfos E-pumps
Motor power range	0.55 to 250 kW (0.75 to 350 hp)
Supply — single-phase	1 x 200–240 V
Supply — three-phase	3 x 200–240 V, 3 x 380–500 V, 3 x 525–600 V, 3 x 525–690 V
Enclosure rating	IP20, IP21 or IP55 depending on enclosure size (NEMA Type 1 and Type 12 equivalents)
Motor types driven	Asynchronous, permanent-magnet and synchronous reluctance motors
Safety	Safe Torque Off (STO) available
Control	Sensor inputs and external control signals for quick adaptation of pump speed to actual demand; optional energy optimisation
Rated output current per model	Not published in the supplier datasheet held by Fresh By Design — we match the drive to your motor's full-load current from its nameplate

Downloads

Grundfos CUE Variable Frequency Drive Spec Sheet

Frequently Asked Questions

How do I choose the right VFD?

Will it fit my existing pump?

What is the difference between CUE and MGE?

How much will it actually save?

Does it give soft start?

Can it be mounted outside a switchboard?

How do I get a price?

Spare Parts & Consumables

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Grundfos Variable Frequency Drives (VFD)

Product Information

Key Features

Specifications

Downloads

Frequently Asked Questions

Spare Parts & Consumables

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