What costs are associated with different motor technologies and systems?

Rob Keating

October 14, 2021

What costs are associated with different motor technologies and systems?

No matter the technology application or solution, there is a motor for it. But with so many motor technologies to choose from, coupled with upcoming innovations changing the motor application game, it can be difficult to know which motor is best for you and your company’s needs.

Efficiency is one of the underlying motives and key benefits in motor selections today. What motor or drive system will be the most efficient, quiet or reliable, while allowing you to have the required speed and torque control your application needs, and, most importantly, the most cost effective for your application? Cost is clearly a major factor when looking into your options for motor technologies for your next project.  

Using our extensive knowledge and experience, we have collated a list of the most popular drive systems and motor technologies to provide you with insights into what costs and trade-offs you’ll need to consider, before making the best-informed decisions.

Motor Technologies

Induction Motor

The induction motor is one of the oldest and most widely used types of technology available. It is effectively a ‘set and forget’ solution, suitable for many different applications. Ideal for those that require a single speed or direction output, they will run to the precise specifications needed.  

This motor typically requires minimal maintenance to run and is extremely reliable given the absence of components such as magnets, commutators or slip rings. Furthermore, with no need for electronic componentry, the induction motor is easier to implement, making it a popular choice for many applications. It is extremely robust, reliable and without permanent magnets, great for applications that use higher temperatures.  

If you are looking for a more cost-effective choice, this may suit your needs perfectly. There is a plethora of options available, and many companies produce them, making it easy to source the ideal motor.  

Induction motors do have some limitations; Without a full range of speed and low starting torque, they won’t be suitable for all applications. They will be physically heavier with lower levels of efficiency and are best suited to applications that are stationary and non-mobility based.  

For many applications, an induction motor will be a more cost-effective choice, however because of its limitations, the overall system may cost more to compensate for this. As one of the first types of motor invented and a cheaper alternative to a PMSM, there is always a place in the market for these great motors.  

 

Permanent Magnet Synchronous Motor (PMSM)

We are seeing more PMSM motors being applied in applications today. They are typically seen as the better alternative to the AC induction motors that previously swamped the market, due to their lower complexity and much more precise speed and torque control (particularly starting torque from zero speed).  

PMSM motors tend to have better efficiency overall due to their ability for wide ranges of performance and speed. They also deliver more opportunities in terms of user experience, as you can cater the motor’s performance to the diversity and value of the application’s needs.  

The overall cost of this motor may be slightly higher than the induction motor, due to the need for a controller and the added cost of the required electronic components and magnets. However, with the cost of electronics continually decreasing, it can become more cost-effective to invest in a more complex motor. This means you get a more intelligent motor, a more efficient system overall, and increased value for the end user.  

 

PMSM: Brushless PMSM Motor

Brushless motors are an extremely popular choice and are becoming dominant in the world of cordless power tools. Although they have been around for some time, they have gained traction in recent years, with new releases by companies such as Makita and DeWalt. There are several key advantages of brushless motors, mostly around the absence of brushes and a commutator. They also tend to run cooler, supplying increased efficiency and they can convert more electricity into power.

Brushless motors tend to be more expensive due to the added cost of the use of permanent magnets, the communicator and electronics required to manage the system properly. Including these components is effectively the beginning of building a computer inside the device and therefore drives costs up. This often makes them better suited to companies with a wide range of applications and those who can invest fully in these motors. As the cost of controllers and electronics continues to decline, it brings the brushless motor within reach of more applications.

PMSM: Brushed DC Motor

Brushed motors are proven to be effective and have been used for many years. They can be applied to many applications, depending on the functionality and specifications required. The brushed motor functionality works on the same principles as brushless e.g., attraction/repulsion between coils and permanent magnets, making them ideal for applications where only one direction of rotation is needed, and the speed or torque doesn’t need to be controlled. A brushed DC motor is not recommended for applications where reduced noise is needed, or those that carry a higher risk of ignition.  

The overall cost of a brushed motor will come in lower than a brushless motor as it lacks the sophisticated electronics of a brushless, however brushed motor technology has a long history and manufacturing costs are typically lower.  

SRM: Synchronous Reluctant Motor

The SRM motor is not a new player in the market having existed for some time, however it is not widely used. This cost-effective option carries an improvement in efficiency compared to an induction motor and is most suited to stationary or non-mobility applications such as HVAC. It is a reliable choice and does not contain magnets.  

The main drawbacks of this motor are increased noise and vibration, which can be problematic for many applications. There are also drawbacks around controllability and power density is not comparable to a PMSM.  

Drive Systems

Engineers have historically looked at innovative ways to change the drive system game, by looking at how to reduce costs, make a more efficient and reliable system, and fine tuning them by adding or removing componentry.

Direct Drive

An efficient system overall, the Direct Drive can be ideal for many applications. It maximises speed and efficiency, is quiet, and it proves to be a reliable system which has paved the way for the innovative drive systems used today.

Direct drives offer a host of benefits. Due to the lack of parts and components, simplicity is a key advantage, along with reduced risk of parts failure. Compact, frameless designs coupled with dynamic acceleration and exceptional power density, mean the motors can be applied to many different applications.  

Read more about Direct Drive motors here>>

Transmission Drive

What is the purpose of a drive-shaft? - Motor Vehicle Maintenance & Repair  Stack Exchange

The transmission drive system consists of a driving machine (the motor) and a driven machine (machine system). The motor itself can be constant or variable RPM, with the machine system requirements differing depending on the application.  

Transmission drive systems are effective when there are multiple different speeds of rotation in a machine an application needs to focus on to achieve its desired goal. Transmissions can be mechanical, electric, hydraulic, or pneumatic, meaning they can be used in multiple types of applications. Some sort of clutch is needed for functional or safety reasons.  

Transmission drives are ideal when needing different speeds of rotation of the machine in your applications. Constant transmission drive systems may include gearboxes, chains and/or belts, which can be more costly, but may be needed to achieve the required performance of your application and to add value to your end user. Space constraints in an application might require a space-saving transmission drive – which can also incur higher costs.

Conclusion

In this brief overview we have covered how costs can vary depending on the type of technology in question, along with the choice of drive system. Choosing the right motor for your application is the first step, working within your budget, deciding how many drive systems you require, along with your application’s specific requirements, will help to determine which option is best suited to your needs.

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