First Electric Motors
Shortly before the invention of the very first electric motor, there were huge advancements in the production and use of the battery. This helped to lay a solid foundation in which the electric motor could be invented using the research conducted in electromagnetic fields and magnets. So, who invented electric motors?
The first known electric motor was developed by and Andrew Gordon in 1740. By 1820, Andre-Marie Ampere had discovered the Ampere force law. This new force law named by Ampere himself was a new electric motor principle that said a mechanical force was produced by interactions between magnetic fields and electric currents.
British chemist and physicist, Andrew Faraday, then made the biggest breakthrough by discovering how electrical energy converts into mechanical energy.
Faraday is considered to be the true inventor of the motor but his ability to create the first motor was only possible by the hard-working scientists working in electromagnetism before him.
Looking through the history of electric motors, the earliest motor to be used in production was one powerful enough to operate a small printing press created by Thomas Davenport in 1834.
A DC motor is powered from a direct current (DC) typically from a battery, DC power supplies or an AC-DC power converter. The construction of a DC motor includes brushes and a commutator which changes the way in which they are maintained. Speed is limited and the life expectancy is shorter than that of an AC motor. The speed of a DC motor is controlled by varying the armature (rotating part) winding’s current.
DC motors are most commonly used in:
- Cranes and hoists (pre-90s)
- Old traction systems (trams and cable cars)
- Fairground rides
- Car door locks, mirror adjusters, wiper motors, and starters
An AC motor is powered from an alternating current (AC) which periodically reverses direction and is powered by power plants and generators. AC motors are not constructed with brushes, are very rugged in design and have much longer life expectancies than that of a DC motor. An AC motor is controlled by varying the frequency using an adjustable frequency drive control.
AC motors are most commonly used in:
- Modern high power engineering and traction systems (railways)
- Commercial tools (power drill)
- Household appliances (vacuum cleaners, blenders, and washing dryers)
- Electrical power plants
- Shipping industry (cargo pumps)
- Transport (monorails, roller coasters, and ground-based rails)
Ironless or Coreless Rotor Motor
In conventional iron-core, brush-type DC motors you will find iron losses. With an ironless type DC motor there are no iron losses with low friction and a good thermal dissipation. This makes ironless DC motors extremely efficient. The low-inertia rotor allows for quicker speeds and faster reaction time also. The linear torque-speed of an ironless motor fits well with simple drive circuits which is why you may see this simple electric motor used in battery-operated equipment such as hand tools or electric toys.
Pancake or Axial Motor
Cedric Lynch designed an axial motor in 1979. The DC motor was able to hold the magnets in place with a rotating armature which was initiated by moving brushes as the rotor. This created a lightweight and compact axial motor perfect for electric bikes.
This same design is now being discussed for use on our modern-day electrical vehicles (EV). Axial motors are often referred to as ‘pancake motors’ due to their big diameter and small length. They can then be stacked up like pancakes on a regular shaft which can create larger outputs making them perfect for electrical vehicles.
Servo motors are small in size but are highly powerful and extremely energy efficient. This has made them perfect for applications such as robotics in the manufacturing, pharmaceutical, and food industry.
Inside a servo system, you will find a small DC motor, servo drive, and a control circuit. Gears allow the motor to attach to the control wheel. Once the motor begins to rotate, the analog servo drives resistance changes which allow the control circuit to regulate the movement with superior precision and direction.
Stepper motors are a type of DC motor that moves in discrete steps. The multiple coils inside the motor are organized in groups known as ‘“phases”. Each phase is energized in a sequence which makes the motor rotate one step at a time.
Using a stepper motor in conjunction with computer-controlled stepping you can achieve extremely high precision positioning and/or speed control. Therefore, stepper motors are used in:
- 3D printing machines
- Textile machines
- Printing presses
- Small robotics
- Gaming machines
- Medical imaging machines