How to Replace a Brushed DC Motor with a Stepper Motor

An emerging trend in the motion control industry

If you want to replace a brushed DC motor with a stepper motor then this is perfectly possible but there are one or two things you will need to be aware of before attempting this.

Many companies are increasingly replacing DC motors with brushless DC motors and brushless motor controllers in a wide range of systems.

You can find out more about this by reading our article on replacing brushed DC motors with brushless motors.

However, swapping DC motors to stepper motors and controllers is less common. That said, as with lots of things in life and in engineering, just because something is not common, does not necessarily make it a bad idea. There are a number of specific applications in which replacing a brushed DC system, (particularly a geared DC system) with a stepper motor and controller can be a very sensible choice.

Why should I replace a brushed DC motor with a stepper motor?

The simple benefits of doing so are that you will improve the lifespan of the system you have (stepper motors only have bearings as parts that can wear out as opposed to brushes).

Stepper motors also improve the range of performance options available (they can turn a fixed number of degrees easily). This will significantly increase the potential of the system you are using and can open a huge number of possibilities. A simple example of this is that you could replace several different motors (and potentially even motor / gearbox combinations) with one programmable stepper motor and controller and get all of the performance options you need from the one package. This enables you to buy the same system in bulk (thereby benefiting from the associated economies of scale) but also enables quick and simple changes to be made to customise the setup for your customers. 

Similarly, if you are using a brushed DC motor in an application such as pumps or process control where the best level of accuracy you may be able to achieve may be related to timings and or additional flow sensing equipment, a stepper motor and controller could help remove all of this additional equipment. How?

Replacing geared DC motors with stepper motors and controllers in dosing applications

 What is more common is to replace geared brushed DC motors with a stepper motor in applications such as pumps, lab equipment and similar applications where positional accuracy can be improved vastly by using a stepper motor and stepper motor controller.

Many applications were addressed in years gone by by using a geared DC motor and timing as a means of dosing and measuring –  however developments in stepper motor controller technology such as on the ZD10 Stepper Motor Controller means that huge advances have been made in the accuracy, flexibility and performance of such systems.

Of equal importance, the cost of such technology has dropped considerably in recent years, making advanced performance options affordable to a broad range of applications.

Whereas 10 or 20 years ago a programmable stepper motor controller such as the ZD10 would have cost £1000+, these days it is much less.

The result of this trend is that many people and companies have started to look at replacing geared brushed DC motors with stepper motor controllers as a means of improving the performance of the system and also as a way of adding more features.

Don't forget to do your homework

The key to being able to replace brushed DC motors with stepper motors successfully is making sure you know the performance characteristics and key specifications of the motor that you are wanting to replace and then being able to make an appropriate match with a stepper motor and controller. If you are not sure how to find out the performance characteristics of the motor (and gearbox) that you have you can start with the part number of the motor and research that. Key characteristics to look for are max and nominal RPM and torque.

Once you have these details you then need to source an appropriate stepper motor with the right performance characteristics. Don’t forget to check the torque speed curve of the motor to make sure it will deliver the torque you need at the speed you want (if you are not sure about this you can find out more about this by reading our guide to understanding torque speed curves). If you have any questions at all about implementing this system then you can always contact us and talk to one of our engineers about your specific project or application.

What next?

If you have an existing project where you are looking to replace a DC motor with a stepper motor and controller you could start by having a look at our online shop where we have a range of stepper motors, stepper motor controllers and recommended motor and controller packages.

If you have any questions about anything that you have read above please feel free to contact us to discuss.

Categories: Brushed DC Motor FAQs, Stepper Motor Controller FAQs
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