Decoding Motors: Differences Between Servo and DC Motors 

Servo Motors and DC motors are highly used machinery assets for different applications within the manufacturing industry. The distinctive difference between the two types of motors is control, precision, and application. 

Servo Motors are commonly used in CNC machines, robotics, and industrial automation. Strong precision makes a servo the go to motor for automation. Torque control is a key benefit, providing control at high and low speed, for machining applications cutting through tough materials or applying significant force during the operation. 

DC Motors are commonly used in Electric Vehicles, HVAC systems and Conveyor systems. The build of the motor is simple, which contributes to the reliability of the motor, ease of maintenance and durability. Providing high-efficiency levels, a DC motor converts electrical energy into mechanical energy with minimal loss. This is a benefit for businesses to reduce operating costs, also helping to become sustainable and reducing environmental impact as a business by a reduction in energy usage. This is crucial to maintain ISO 14001 standards, Environmental Management System regulations.   

Key differences between a Servo Motor and a DC Motor 

Servo and DC motors have different characteristics, as they are each suitable for different applications within the industry. The key differences are:   

Control Mechanism:  

Servo motors are designed for precision and positioning when running. Built with a feedback system, such as an encoder, to provide information on speed, direction and position when machining. This type of motor is controlled using a closed-loop control system.  

DC Motors are controlled by a signal that determines speed and direction, but not position, using an open-loop control system. 

Torque Output (Torque is the force within a motor): 

Servo’s higher torque capability allows them to control heavier loads to high precision.  

DC motors have varying torque depending on the specific type of motors, brushed or brushless. This type of motor cannot guarantee the same torque output as a Servo.  

Speed Control:  

Servos have the capability to consistently maintain a set speed as a result of the closed-loop system, and can quickly change their speed to the requirement.  

A DC motor can control the speed, however the accuracy can be affected if changes to the speed are continually altered. A DC motor will run better when set at one speed.  

Choosing your Motor 

It is crucial to investigate the specifications of the application in order to determine the appropriate motor for machining purposes. This will enhance the accuracy and effectiveness of your equipment. Neutronic suggests researching the following before investing in a Servo or DC Motor: 

Precision Requirements – If you require machining at high precision, a servo motor will meet this demand and offer accurate speed and precision when machining. A DC motor is suitable when precision control is not as critical, and simplicity and cost are key focuses.  

Compatibility Requirements Consider the implementation of the equipment into existing systems, such as communication, compatibility with controllers and programming tools.  

Cost Consideration – DC motors are considered to be more cost-effective than Servo’s, due to their build simplicity. However, consider the application requirements to make sure the investment meets the performance requirements to produce a successful ROI on the asset investment.  

Investing in a Motor? 

Our account managers at Neutronic can offer outstanding advice, if you are unsure about which motor is best suited to your manufacturing needs. Neutronic can source motors from a range of major manufacturers such as SEW-Eurodrive, WEG and ABB with reduced lead times and outstanding prices.  

Contact our team on 0845 180 0483 to discuss this further, or take a look at our supply page! 

Industry Application  

As discussed throughout the blog, different industries will require different motors to meet the manufacturing requirements. An example of an industry application is a Servo Motor being used within a CNC machine.  

A CNC machine requires high precision, this is crucial within CNC machining as they machine complex part with a high-quality surface finish. Servos offer control of speed and acceleration making it easy to adjust the speed of machining throughout the programme.  

The closed-loop control used within the Servo is what contributes to the accurate positioning when machining, which is why improved performance is offered, in comparison to a DC motor for this specific industry application.  

Read More

Reasons for Servo Motor Failure

There are numerous reasons why Servo Motor failures happen. It’s crucial to understand the preventative maintenance measures you can implement to minimise the likelihood of unforeseen motor failures. A Servo Motor can be affected by Electrical, Mechanical, or Environmental factors, which can hinder its operation. 

Run Testing a Servo Motor

Most manufacturers estimate a machining lifespan of 20,000 to 30,000 working hours for servo motors, although this can fluctuate based on the application and maintenance performed on the servo. 

This blog will explore 5 potential causes of Servo motor failures and suggest methods to optimize the efficiency of the Servo Motor. 

Continual operation of a servo motor at high temperatures, or without adequate cooling intervals can lead to overheating. Persistent overheating can eventually lead to motor failure, as it damages the internal insulation and diminishes the motor’s efficiency. 

To avoid overheating in the Servo, it is advisable to improve the regulation of heat distribution within the servo. Regular upkeep of the servo can help detect worn-out parts; replacing these parts can minimize the heat generated during rotation. Allowing extended cooling periods will assist the motor in resetting its temperature before it starts operating again. 

Degraded Bearings 

Continuous spinning inside the Servo can degrade specific parts, with bearings being a prime example. When a bearing deteriorates, it can cause the motor to become loud or even stall. Bearings play a crucial role in a servo, as their degradation can affect the accuracy during machining. 

Increased friction is produced when bearings are worn out. This friction can elevate the temperature while the motor is in operation, and potentially lead to the motor overheating, which is an adverse effect. 

Environmental Consequences 

The environment in which the Servo motor operates can influence its effectiveness, especially if it’s not an appropriate setting. Environments that are corrosive, hot, or humid can heighten the risk of motor breakdowns and diminish the dependability of the Servo Motor. This factor should be considered when choosing the motor for a specific task, ensuring it can endure the environmental conditions. 

Intrusion of dust or liquids can negatively affect the motor and its internal parts. Monitoring the dust accumulation within the servo is crucial, as excessive dust can pose a fire hazard within the motor. 

Servo Motor Maintenance Obligations 

Maintaining machinery is crucial for detecting and fixing issues before they inflict internal damage to other parts. Regular inspections of lubrication levels, cleanliness, and motor balance are essential aspects to be examined when the motor is frequently in operation. 

Servo Motor Vibration Issues 

Vibration in the motor can lead to misalignment, as the motor’s movement can displace internal components. If your servo is vibrating, this is an indication that it needs to be inspected and rebalanced to reduce the vibration. At our Neutronic workshop, we utilize our CEMB 2000 or ZB20/TCN/GV balancing machines, essential tools for motor repairs. Every motor that exits our workshop is rebalanced to G1.0, enhancing its efficiency and lifespan. 

Our servo motor specialists at Neutronic possess the skills to detect, correct, and test the servo motor to ensure it operates at OEM specifications. Email Neutronic today to schedule your Servo Motor repair today! 

Read More