Electric Motors & Engines

Explained Electric Motors & Engines
 

Simply put, an electric motor is a mechanism that uses electricity to generate mechanical motion. Most electric motors function as a result of the interaction between the magnetic field of the motor and the electric current in the wire winding. According to Faraday's Law, this interaction exerts a force on the motor's shaft in the form of torque.

Direct current (DC) sources, like batteries or rectifiers, can be used to power electric motors. Alternating current (AC) sources include things like power grids, electric generators, and inverters.

If it weren't for the invention of the motor, we'd still be using electricity for nothing more than powering light bulbs in the style of Sir Thomas Edison.

Vehicles, railroads, power tools, fans, air conditioning, home appliances, computer disk drives, and many more things all require electric motors. Even tiny motors can be found in some battery-operated wristwatches.

The History
 

In 1821, British scientist Michael Faraday described how a conductor carrying an electric current might be turned into a mechanical energy source by placing the wire in a magnetic field and using the torque created by the electrical current and field to cause the conductor to rotate.

One more British scientist, William Sturgeon, used his idea to create the first machine in 1832—a DC (Direct Current) machine, the most basic type of electric motor. However, his prototype was too costly for its limited utility.

The first electrical motor was created by physicist Frank Julian Sprague later in 1886. That could maintain a fixed rotational speed over a wide variety of loads, producing a driving force.

Types of Electric Motors and Engines
 

1. Stepper Motors

In stepper Electric Motors & Engines, the rotor is located on the inside and is controlled electronically by magnets on the outside. Permanent magnets or a flexible metal can be used to construct the rotor. When the windings are turned on, the teeth on the rotor line up with the magnetic field. Because of this, they can go from one location to another at a consistent rate. It's important to weigh the pros and cons of the various motors before beginning development on a new system. Picking the proper motor is a great first step in completing any task.

2. Servo motors

Servo motors are the workhorses of robotics, since they consist of any motor combined with a feedback sensor to aid in positioning. Actuators, both rotary and linear, are implemented. Although inexpensive brushed DC motors have been widely used up until recently, high-performance brushless AC motors are now the norm.

3. Liner Motors

These electric motors have a stator and a motor that have been unrolled, allowing them to generate linear force along the device's length. They differ from cylindrical designs in that their "active" section is flat and has two ends. In comparison to rotatory motors, they tend to be quicker and more precise.

4. Direct Drive

When traditional servo motors and transmissions are replaced with direct drive, the result is increased efficiency and decreased wear. These motors accelerate quicker and are much simpler to maintain over time.

5. DC Brushless Motor

DC brushless motors were originally designed to outperform DC brushed motors while taking up less room. They are also more compact than equivalent AC motors. When a slip ring or commutator is not present, an integrated controller is used to allow for operation.

6. DC Brushed Motors

Brush orientation on the stator of a DC brushed motor is what controls the direction of current flow. Instead, the orientation of the brush with respect to the individual segments of the rotor bar is critical in some types. Every DC brushed motor layout relies heavily on the commutated.

7. AC Brushless Motors

Popular in the field of motion control are AC brushless motors. The stator generates a spinning magnetic field, and the rotor is inducted into that field to cause simultaneous rotation. To function, they need constant access to electromagnets.

How To Choose The Best Electric Motors & Engines
 

1. Current

Since current provides the energy for the motor's operation, excessive amounts of it might cause malfunction. Operating and stall current are crucial for DC motors. The operating current of a motor is the average amount of power it is designed to use at a certain torque setting. As the name implies, stall current provides enough torque to keep the motor spinning at zero revolutions per minute (RPM). When multiplied by the rated voltage, this is the maximum power that the motor should be able to produce by drawing from the electrical supply. To prevent the coils from melting, a heat sink must be used when operating the motor continuously or at a voltage higher than the rated value.

2. Voltage

Its purpose is to prevent the flow of current from reversing and to overcome any existing back current. When the voltage is increased, the torque is also increased. The maximum recommended operating voltage for a DC motor is indicated by the motor's voltage rating. Always use the specified voltage. 

Consider both the operating and stall numbers beside the torque. Stall torque is the amount of torque produced when power is provided at the stall speed, and operating torque is the amount of torque the motor is able to provide in normal operation. 

3. Velocity

Calculating motor speed (in revolutions per minute) can be a challenge. Even while higher speeds are ideal for motor efficiency, they aren't always achievable due to the need for gearing. The motor's efficiency will go down if you add gears, so you'll need to think about slowing down and losing some torque.

4. Motor Function

Prioritizing motor performance took a back seat to understanding the factors of an application that could limit the motor type selection. Can you describe the function(s) of the motor in this context? The functionality of a motor can be evaluated in terms of its speed and torque, its starting/stalling torque, and its duty cycle or load profile. Motor size is determined in part by the speed and torque output needed to run the application. 

5. Specifications of The Motor

When evaluating potential new projects, motor housing design is often one of the first factors to be thought about. As the designer, you need to know how much weight and space the product can take up in order to do its job. 

A long, thin motor may be needed for one task, whereas a shorter, fatter motor may be more suited to another. The choice of motor might be impacted by whether or not the application requires a lightweight product.

Do you require a motor that runs for 10,000 hours without any maintenance, or will you only be using it for 200 hours over the next 20 hours? The brushes, the commutator, and the bearings are the primary potential failure points of a motor. 

Environment

The vast majority of motors on store shelves are designed to operate in standard conditions. If the motor will be exposed to dust or water as a result of the project's specifications, the designer should think about using a motor designed for environmentally sensitive applications. An additional thing to think about while making your motor selection is the typical outside temperature.

How Electric Motors & Engines work
 

There are two approaches of working electric motors and engines. The first is to employ alternating current, a type of electric current in which the direction of flow alternates at regular intervals (AC). One better method is to attach a commutator to either end of the coil, as is done in battery-operated motors like the ones we use around the house. (Don't be put off by the useless technical name; this slightly dated word "commutation" is similar to the word "commute"). 

Much like how "commute" can indicate "to travel back and forth," "switch" simply implies "to alter." The commutator's primary function is to flip the direction of the electric current in the coil at regular intervals, typically every half turn of the coil's rotation. 

Half of the commutator is connected to one end of the coil. The terminals on the motor are wired to receive power from the battery. Brushes, which can be formed from bits of graphite (soft carbon like pencil "lead") or thin lengths of springy metal, "brush" against the commutator to transfer electrical current. The commutator ensures that the coil always spins in the same direction when current is passed through the circuit.

Conclusion

As the name implies, electric motors use electricity to create motion. Most of them generate torque on the motor shaft by the interplay of the motor magnetosphere and electrical current in a coiled wire. The rotor and the stator are the heart and soul of any motor. They can be powered by either direct or alternating current. Induction motors, servo motors, three-phase motors, and industrial motors are just a few of the various varieties of electric motors available. They find application in a wide variety of vehicles, including electric ones, air conditioners, ships, and hydraulic machinery.

FAQs: Electric Motors & Engines
 

Q. What is the difference between engine and electric motor?

Ans. While a motor can only convert electrical energy into mechanical form, an engine can convert it along with multiple others.

Q. Why are electric motors better than engines?

Ans. Vehicles powered by electric motors are far more fuel efficient than those powered by conventional internal combustion engines (ICEs). When compared to a gas combustion engine, which converts less than 40% of its fuel into mechanical energy (in the form of motion), electric motors are more efficient.

Q. What are the pros and cons of electric motors?

Pros:

• Since they have more moving parts, electric motors last longer.
• Electric motors can operate for up to 30,000 hours with regular servicing.

Cons:

• Large electric motors are cumbersome to relocate and demand careful attention to the supply voltage and current.
• In other circumstances, remote areas without access to electricity require expensive line additions.
   

Q. Are electric engines better?

Ans. Yes, In addition to being more environmentally friendly, electric motors are also more productive.