Two Speed Motors

  Enquiry / contact me

Two speed motors can bring flexibility to many machines. For Exico, one of the few suppliers of this technology in the UK, the greatest advantage of two speed motors is their simplicity and reliability

Motors & Drives

The many advantages of the two speed motors
The many advantages of the two speed motors

Most engineers practising today will have grown up with inverters or electronic variable speed drives, and are specifying them more and more often as a way to meet increasingly stringent energy management requirements. In fact you could say that inverters really are a technology for today's world.

They first emerged in the 1980s, were perfected in the 1990s and really came into their own after the Millennium as a way to reduce energy usage, thus helping manage global warming and climate change. An inverter lets you turn down the speed of a motor and thus reduce its energy consumption, and very significant savings can be made. Given that about half of the world's electricity is used to power motors, the inverter unlocks huge potential energy savings.

It is perhaps not surprising that people took to inverters and, for a while, tended to forget alternative solutions for speed control. However in recent years there has been a renewal of interest in two speed motors, leading to an increase in their sales and installation. For Exico, one of the few suppliers of this technology in the UK, the greatest advantage of two speed motors is their simplicity and reliability.

While they do not provide the infinitely variable speed control of an inverter, they can be ideal in applications that require 'high' and 'low' speed settings rather than total adjustability. They are simple to install, have a long working life, are bombproof in terms of reliability and do not require the extra space of an inverter.

Technical advantages

As well as these technical advantages, two-speed motors can be good for plant and machines that are going to be located in areas where support services are less than ideal, in remote locations and where environmental or operational conditions such as extremes of heat, cold and humidity, vibration, water ingress and impacts could strain electronic circuitry.

Typical applications where a two-speed motor may be preferred over an inverter set-up include the many pump and fan applications that need two set speeds. There are many such applications in the water distribution industry where there is basically a daytime demand level and a lower night time one. Another potential application area is HVAC (heating, ventilation and air conditioning) pumps and fans in office buildings that are occupied 8-10 hours a day for five days and virtually empty the rest of the time.

In the industrial world, some conveyors have predictable light and heavy load requirements so would benefit from twin-speed capability. Cranes and winches often need a fast setting for long lifts and a slow setting for other duties. Of course, many of the pumps and fans in industry may benefit from for a two-speed drive capability.

Operating principles

One of the great practical advantages of two speed motors is that they look very like standard fixed speed motors, at least from the outside. This means maintenance technicians are not usually wary of them, that they generally fit into the same spaces as regular motors and are mounted in the same way.

However, internally they are quite different. In fact there are two principles upon which they can work, dual winding and pole changing. At first glance a dual-wound motor rotor looks remarkably like a conventional one, but closer inspection reveals that there are in fact two windings, each separately connected to the power. Put simply: switch on one rotor and you have the first speed; switch on both rotors and the second speed comes into play. A closer look reveals that the rotors, while in the same lamination pack, are configured to have opposite polarities.

Posted on February 8, 2016 - (596 views)
Exico Ltd
Unit 8 Denington Industrial Estate
NN8 2QF Wellingborough - United Kingdom
View full company profile
Related articles
Guiding Energy and Data at High Speeds
Electronic Drives for Bicycles
Optimized Solution of Constant Force Spring for Carbon Brush
Electric Track Drive
Planetary Gearboxes
Power Density in Robotics
Dimensioned and Efficient Drive Systems
Power Spring for Draw Wire Encoder Application
Polyvalent Compact Machine Controller
Linear Conveyor Solution Book
Top-notch Products
Power in new Dimensions - BXT Motor Family
Sure Signs of Excellence: Top Notch Products Offering Added Value
Every beginning needs drive
Coil Winding Expo Berlin, June 19 to 21 2018
Drives & Controls
BSR Series
Synchronous Reluctance  Motors - Be Fast in an Efficent way
All-in-one Dezentralized Drive System
Miniature- and Micro-Drive Systems
Polyvalent Compact Machine Controller
Shortening Production Life Cycles by 2 Seconds
Driving Amusement Safely: The Thrill is Guaranteed!
Danfoss Drives Presented its Latest Novelties at SPS IPC Drives 2018
Interroll Launches its Versatile Drive Platform at Sauber Motorsport
Brushless Flat DC-Servomotors with more torque
Power in new Dimensions - BXT Motor Family
Integrated Servo Motor
Bonfiglioli BSR Synchronous Reluctance Motors
Motion Controller from FAULHABER with STO shutdown