Home › Electric Motors › Three Phase To Single Phase Motor Conversions

Three Phase to Single Phase Motor Conversions

An in-depth guide to three phase motors for industry. How they work, types, applications & how to choose – plus our stocked ranges and IE3 & IE4 options.

Car Lift Conversions

Car Lift Conversions

High starting torque for demanding applications. Ideal for car lifts, compressors, conveyors, woodworking machinery, and gearboxes. 0.18kW (0.25hp) to 3.7kW (5hp).

Lathe Motor Conversions

Lathe Motor Conversions

Low starting torque for applications such as pumps, fans, blowers, and ventilation. 0.09kW (0.12hp) to 3.0kW (4hp).

Compressor Conversions

Compressor Conversions

Safe for construction sites and portable equipment where a 110V is mandatory. Ideal for workshops, site tools, and temporary installations.

NEED HELP CHOOSING A SINGLE PHASE MOTOR TO REPLACE YOUR THREE PHASE MOTOR?

Use our quick Motor Selection Wizard to get the right motor first time

Find My Motor

Three Phase to Single Phase Motor Conversions

Converting equipment from 3-phase to single-phase power? You're in the right place.

MM Engineering Services specializes in converting three-phase motors to single-phase replacements—and we've successfully done this for thousands of industrial machines, car lifts, lathes, pillar drills, table saws, and workshop equipment.

Unlike generic online forums or mass-market retailers, we understand the specific requirements of each machine type. A conversion solution for a car lift is completely different from a lathe—and we solve both correctly the first time.

When Conversion Makes Sense:

✅You have single-phase power only (230V) at your premises
✅Your equipment is three-phase (400V)
✅You want to avoid the cost of three-phase installation (£2,000-5,000 from your energy supplier)
✅The equipment is worth keeping (car lifts, high-quality lathes, industrial drills)

When Conversion Doesn't Make Sense

❌If equipment is already single-phase – no conversion needed
❌If you're discarding the equipment – not worth the investment
❌If you have three-phase power available – use it as-is (more efficient)
❌If multiple three-phase motors need converting – consider three-phase installation instead

Three Conversion Methods Compared

Choosing the right type of single phase motor depends on your starting torque requirements and application.

Single Phase Motor Replacement **Most Common**

What it is: Replace the three-phase motor with a direct equivalent single-phase motor.

  • ✅ Most cost-effective
  • ✅ Simplest installation
  • ✅ Best long-term reliability (no external converters needed)
  • ✅ No ongoing maintenance (motor is all you need)
  • ✅ Faster speed availability (most sizes in stock, same-day delivery available)
  • ✅ Excellent support (we've installed thousands of these)
  • ❌ Limited power range (single-phase motors max out at ~3.7kW / 5HP in UK)
  • ❌ Higher starting current (domestic circuit breaker needs replacing to Type C)
  • ❌ No speed control

Phase Converter ** Best for Speed Control

What it is: An electronic device that converts single-phase 230V power into three-phase 400V power electronically.

  • ✅ No motor replacement needed (keep original equipment - must be 230/400V)
  • ✅ Variable speed control (run motor at any speed from 0-100%)
  • ✅ Soft starting (gradual acceleration reduces shock)
  • ✅ Protection features (thermal overload, phase failure protection)
  • ✅ Compact
  • ❌ ALOT Higher cost than single phase motor replacement
  • ❌ More complex installation
  • ❌ Loss of torque and power
  • ❌ Not ideal for all equipment (some equipment designed for fixed speed)

Car Lift Conversion - A Complete Guide

Capacitor start/capacitor run motors (also called CSCR or two-value capacitor motors) are designed with two capacitors, which allow them to deliver the highest starting torque of any single phase motor type – typically 1.8-2.5 times the rated torque. This makes them essential for applications with high inertia loads or where the motor must start under load e.g. Car Lift, Compressors or Conveyor.

How They Work These motors use two capacitors: a large start capacitor and a smaller run capacitor. At startup, both capacitors are in circuit to create a strong phase shift that produces high starting torque. Once the motor reaches approximately 75% of full speed, a centrifugal switch disconnects the start capacitor, leaving only the run capacitor in circuit for efficient continuous operation.

Ideal Applications

  • Car lifts and vehicle hoists
  • Air compressors and refrigeration compressors
  • Conveyors and material handling
  • Woodworking machinery (saws, planers, thicknessers)
  • Gearbox-driven equipment
  • Crushers and grinders
  • Any application with high starting loads

Our Range We stock capacitor start/capacitor run motors from 0.18kW (0.25hp) to 3.7kW (5hp) in 2-pole (3000rpm) and 4-pole (1500rpm) configurations. All motors feature high-quality aluminium construction, NSK bearings, IE2 design, complete with Thermal reset switches for added protection and multi-mount design.

Our most popular Car Lift Motors - 2.2kW (3hp) - Hydraulic Driven Car Lifts & 3.7kW (5hp) - Screw/Pulley-Belt Driven Car Lifts
IE2 Efficiency
Amtecs 2.2kW (3HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame
View Details

Amtecs 2.2kW (3HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame

amtecs
IN STOCK

Amtecs 2.2kW (3HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame
£237.72Inc VAT £198.10 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
IE2 Efficiency
Amtecs 3.7kW (5HP) Single Phase Motor 4-Pole (1500 rpm) 112 Frame
View Details

Amtecs 3.7kW (5HP) Single Phase Motor 4-Pole (1500 rpm) 112 Frame

amtecs
IN STOCK

Amtecs 3.7kW (5HP) Single Phase Motor 4-Pole (1500 rpm) 112 Frame
£398.44Inc VAT £332.04 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

Permanent Capacitor Single Phase Motors

Permanent capacitor motors (also called capacitor run or PSC motors) offer reliable, maintenance-free operation for applications requiring low starting torque. With no centrifugal switch to wear out and only one single capacitor, these motors are simpler, quieter, and longer-lasting than capacitor start/run types allowing you to switch them more on/off frequently.

How They Work A single capacitor remains permanently connected in the motor start winding, providing continuous phase shift. This eliminates the mechanical complexity of a centrifugal switch but limits starting torque to approximately 0.3- 0.7 times the rated torque. Once running, permanent capacitor motors are reliable but less efficient than other AC Electric motors.

Ideal Applications

  • Pumps (water, heating, circulation)
  • Fans and blowers
  • Ventilation systems
  • HVAC equipment
  • Agricultural fans
  • Low-inertia loads
  • Equipment with no starting load

Our Range: We stock permanent capacitor motors from 0.09kW (0.12hp) to 3.0kW (4hp). These motors are perfect for applications where the load starts unloaded (like pumps and fans) and smooth, quiet operation is important.

Our most popular Permanent Capacitor Single Phase Motors
IE2 Efficiency
Amtecs 0.75kW (1HP) Single Phase Motor 4-Pole (1500 rpm) 80 Frame
View Details

Amtecs 0.75kW (1HP) Single Phase Motor 4-Pole (1500 rpm) 80 Frame

amtecs
IN STOCK

Amtecs 0.75kW (1HP) Single Phase Motor 4-Pole (1500 rpm) 80 Frame
£157.40Inc VAT £131.17 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

IE2 Efficiency
Amtecs 1.1kW (1.5HP) Single Phase Motor 4-Pole (1500 rpm) 90 Frame
View Details

Amtecs 1.1kW (1.5HP) Single Phase Motor 4-Pole (1500 rpm) 90 Frame

amtecs
IN STOCK

Amtecs 1.1kW (1.5HP) Single Phase Motor 4-Pole (1500 rpm) 90 Frame
£194.91Inc VAT £162.43 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
IE2 Efficiency
Amtecs 0.37kW (0.5HP) Single Phase Motor 4-Pole (1500 rpm) 71 Frame
View Details

Amtecs 0.37kW (0.5HP) Single Phase Motor 4-Pole (1500 rpm) 71 Frame

amtecs
IN STOCK

Amtecs 0.37kW (0.5HP) Single Phase Motor 4-Pole (1500 rpm) 71 Frame
£122.17Inc VAT £101.81 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
IE2 Efficiency
Amtecs 1.5kW (2HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame
View Details

Amtecs 1.5kW (2HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame

amtecs
IN STOCK

Amtecs 1.5kW (2HP) Single Phase Motor 2-Pole (3000 rpm) 90 Frame
£190.83Inc VAT £159.03 Ex VAT
View Details
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock
In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Delivery:

In Stock
Out Of Stock

Single Phase Motor Speed (RPM) Ratings

Our single phase motors are available in various speeds, ranging from 1000RPM to 3000RPM, covering virtually all domestic, commercial and light industrial applications.

Speed Options

Single phase motors are available in three standard speeds:

  • 2-Pole (3000 RPM) – Higher speed, suitable for direct-drive applications like circular saws, pumps, and machinery requiring high rotational speed but have lower torque than a 1500rpm.
  • 4-Pole (1500 RPM) – Lower speed with higher torque, ideal for car lifts, gearbox-driven equipment, conveyors, and applications requiring more turning force.
  • 6-Pole (1000RPM) – Some applications also use 6-pole (1000 RPM) motors for very high torque requirements.
Our 2 Pole (3000RPM) Motors Our 4 Pole (1500RPM) Motors

Single Phase Motor Power Ratings (kW)

Our single phase motors are available in various powers, ranging from 0.09kW (0.12hp) to 3.7kW (5hp), covering virtually all domestic, commercial and light industrial applications.

  • Power (kW) Power (HP) Typical Applications
  • 0.09 - 0.18 0.12 - 0.25 Small fans, pumps, polishing machine.
  • 0.25 - 0.55 0.33 - 0.75 Ventilation fans/blowers, pillar drills, lathes with clutch systems.
  • 0.75 - 1.5 1.0 - 2.0 Pumps, circular saws, small machinery.
  • 2.2 - 3.7 3.0 - 5.0 150ltr+ Air compressors, car lifts, log splitters, heavy machinery, industrial equipment.

Single Phase Motor Frame Sizes Explained

Electric motors come in various frame sizes which determines the physical dimensions of the motor, including the mounting hole positions, shaft height, shaft diameter, length and keyway details. It is essential to match the frame size when replacing an existing motor.

Common Frame Sizes

  • Frame Shaft Height Typical kW Range
  • 56 56 mm 0.09kW (0.12hp) - 0.12kW (0.16hp)
  • 63 63 mm 0.12kW (0.16hp) - 0.18kW (0.25hp)
  • 71 71 mm 0.25kW (0.33hp) - 0.55kW (0.75hp)
  • 80 80 mm 0.55kW (0.75hp) - 1.1kW (1.5hp)
  • 90 90 mm 1.1kW (1.5hp) - 2.2kW (3hp)
  • 100 100 mm 2.2kW (3hp) - 3.0kW (4.0hp)
  • 112 112 mm 3.7kW (5hp) - 4.0kW (5hp)

Single Phase Motor Mounting Options

All our single phase motors feature multi-mount design with removable feet, allowing flexible installation. Standard mounting options include:

B3 (Foot mounted)

The most common configuration, where the feet are bolted to a base/mounting plate.

B5 (D Flange mounted)

Large flange for mounting direct to equipment. No feet required.

B14 or B14S (Small C Face mounted)

Smaller face flange for compact installation with drilled and tapped holes.

B14L (Large C Face mounted)

Larger face flange for compact installation with drilled and tapped holes.

B34S (Foot & Small C Face mounted)

A combination of a foot mount and a small face mount for a secure fit with maximum flexibility.

B34L (Foot & Large C Face mounted)

A combination of a foot mount and a large face mount for a secure fit with maximum flexibility.

B35 (Foot & D Flange mounted)

Combination mounting with large flange providing both stability on the ground and a direct flange coupling to the driven equipment.

V1 (Vertical Flange mounted with Rain canopy)

Large flange for direct mounting in a vertical position to equipment. No feet required with added protective rain canopy that shields the top of the motor from water ingress, dirt, and debris.

How to wire a Single Phase Motor

Single phase motors have a terminal box with clearly marked connections. Typically: L (Live), N (Neutral), and E (Earth). The capacitor(s) are usually internally wired. Below is our typical wiring diagrams for a Capacitor Start/Capacitor Run and Permanent Capacitor motor and shows the how to wire the motor for clockwise and anti-clockwise rotation.

Single Phase Motor Applications

Single phase motors power equipment across numerous industries and applications:

Agriculture & Farming

  • Grain augers and conveyors • Feed mixers • Barn ventilation fans
  • Water pumps • Milking pumps

Woodworking & Workshops

• Table saws and band saws • Planers and thicknessers

• Dust extraction • Pillar drills • Lathes

HVAC & Ventilation

HVAC & Ventilation • Extractor fans • Air handling units

Pumps & Water Systems

• Borehole pumps • Pressure boosters • Swimming pool pumps

• Pond pumps • Heating circulation pumps

How to Select the Right Three Phase Motor

Selecting the right three phase motor for your application requires matching several key specifications:

  • Specification Description
  • Power Rating Match or slightly exceed the power (W/kW/hp) requirement of your application. Check the existing motor nameplate or equipment manual.
  • Speed (Poles) 2-pole (3000 RPM) for high-speed applications. 4-pole (1500 RPM) for higher torque applications, 6-pole (1000 RPM) for slow and high torque or 8-pole (750 RPM) for maximum torque.
  • Frame Size Measure the existing motor frame size to ensure correct mounting dimensions and shaft height.
  • Motor Type Aluminium, Cast Iron, Brake Motor, Hazardous Area
  • Voltage 230/400V or 400/690V
  • Mounting Type B3 foot, B5 flange, B14 face, or combination mounting (B34 foot & face or B35 foot & flange)

Single Phase vs. Three Phase Electric Motors: Quick Comparison

Electric motors come in various frame sizes which determines the physical dimensions of the motor, including the mounting hole positions, shaft height, shaft diameter, length and keyway details. It is essential to match the frame size when replacing an existing motor.

  • Feature Single Phase Motor 230V Three Phase Motor 400V
  • Voltage (UK) 230V/240V 400V
  • Wiring Connections Live + Neutral (+ Earth) L1 + L2 + L3 (+ Earth)
  • Starting Method Capacitors + Centrifugal Switch Self-starting
  • Max Power Limit 3.7KW (5HP) Almost Unlimited (up to High Voltage)
  • Efficiency Standard - IE1 & IE2 High Efficiency (IE3/IE4/IE5)
  • Starting Torque Medium High
  • Full Load Torque Medium High
  • Variable Speed Control Not suitable for speed control Suitable for Speed control
  • Cost Higher Lower
  • Typical Use Home, Domestic, Small workshops Factories, Large Industrial/Manufacturing sites

Single Phase vs. Three Phase Electric Motors: Real World Example (2.2kW)

See below the actual difference between a 2.2kW single phase motor vs a 2.2kW three phase motor

  • Frame Shaft Height Typical kW Range
  • Voltage (UK) 230V/240V 400V
  • Power 2.2kW (3hp) 2.2kW (3hp)
  • Speed (RPM) Approx. 2800rpm Approx. 2800rpm
  • Frame Size 90L (90mm shaft height) 90L (90mm shaft height)
  • Wiring Connections Live + Neutral (+ Earth) L1 + L2 + L3 (+ Earth)
  • Efficiency IE2 – 83.2% IE3 – 85.9%
  • Starting Method 2 x Capacitors + Centrifugal Switch DOL Starting
  • Max number of start/stops 4-6 per hour 10 per hour
  • Efficiency IE2 – 83.2% IE3 – 85.9%
  • Starting Torque 16.79Nm 18.74Nm
  • Full Load Torque 7.3Nm 7.21Nm
  • Full Load Current 11.7A 4.35A
  • Cost £198.10 + VAT £160.56 + VAT
  • Availability In stock - FREE delivery to UK In stock - FREE delivery to UK

Frequently asked questions
What is a three phase to single phase motor conversion?

It’s adapting equipment designed for three phase supply (400V) so it runs safely and efficiently from a single phase power source (230V).
Can I run a three phase motor on single phase power?

Yes, using a correctly specified converter, VFD, or motor replacement designed for single phase input.
What’s the best way to convert three phase to single phase?

We usually recommend replacing the motor with an equivalent single phase motor matched to load/torque and duty.
Will I lose power when converting three phase to single phase?

Choosing the right kW rating minimises torque and efficiency losses.
Is a new single phase motor better than using a phase converter?

For smaller loads (under 3kW) and long‑term reliability, a purpose‑built single phase motor is often the cleaner, lower‑maintenance option.
What information do you need to specify a conversion?

Motor kW or hp, voltage, speed (rpm/poles), frame size, application, and duty cycle are usually enough.
Can you convert industrial three phase machinery for use in a workshop?

Yes, many pumps, fans, compressors, car lifts and machine tools can be converted with suitable motors and control gear.
Is a VFD (inverter) better than a static phase converter?

VFDs give smoother starting, speed control, and better motor protection, so they’re preferred for most modern conversions.
How long does a three phase to single phase conversion take?

Simple motor swaps can be done in hours; full system upgrades with controls typically take a day or two.
Do you offer advice and supply for three phase to single phase conversions?

Yes, we specify, supply and support motors and drives for three phase to single phase conversions across many industries.