Brushed DC Motor

Duowei Electric: Your Leading Brushed DC Motor Supplier

Why Choose Us?

Wide Range of Applications

Our products can be used in various industries including automotive, industrial automation, robotics, household equipment, medical equipment, HVAC systems, office equipment, defense and aerospace, electrical equipment, and power tools.

Professional Services

We can provide customers with "customized services" to meet their long-term needs through tailor-made products. At the same time, we have more than 20 years of production experience and can provide large-scale electric motor production services.

Quality Assurance

ZWS series brushless DC motors, HC series motors, and YY series induction motors have passed UL certification. HC series motors, YY series induction motors, and YDK series air-conditioning motors have passed 3C certification and obtained "Export Product Quality License"

Mass Production of Various Motors

We have realized mass production of 57ZWS, 83ZWS, 120ZWS brushless DC motors. Besides, the linear motor was also successfully developed and put into mass production.

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Definition of Brushed DC Motor

A brushed DC electric motor is an internally commutated electric motor designed to be run from a direct current power source and utilizing an electric brush for contact. Brushed DC motors can be varied in speed by changing the operating voltage or the strength of the magnetic field. Depending on the connections of the field to the power supply, the speed and torque characteristics of a brushed motor can be altered to provide steady speed or speed inversely proportional to the mechanical load. Brushed motors continue to be used for electrical propulsion, cranes, paper machines and steel rolling mills.

Working Principle of Brushed DC Motor

Brushed DC motors have wound coils in the rotor, which are surrounded by magnets contained in the stator. The two ends of a coil are connected to the commutator. The commutator in turn connects to electrodes called brushes, resulting in the flow of direct current electric power through the brushes and coil for as long as the brushes and commutator are in contact. As the coil rotates, however, it reaches a position where the brushes and commutator are no longer in contact, halting current flow in the coil. Despite this, the momentum of the coil causes it to continue rotating. This brings the brushes and commutator back into contact, restoring the current that now flows through a different coil. This repeated switching of current flow causes the brushed DC motor to continue rotating. Brushed DC motors operate on direct current, and their speed can be easily controlled by altering the applied voltage.

Features of Brushed DC Motors

Put in simple terms, when a power supply voltage is applied to a motor, a current flows and the motor rotates; but the characteristics of the power supply voltage, the rotation rate, the torque, and other quantities are all interrelated. We explain these relations using an equivalent circuit and equations for a brushed motor.

DC Equation for the Closed Circuit: Ea=R×Ia+Ec
Ea: Power supply voltage, R: Armature resistance,
Ia: Motor current, Ec: Motor induced voltage
The power supply voltage Ea is equal to the induced voltage Ec plus the product of the armature resistance R and the motor current Ia. The armature resistance has resistance components due to the windings and to the core. That the voltage is equal to resistance times current is precisely Ohm's law. The induced voltage is the voltage that occurs due to rotation of the motor (electricity generation), and is an additional voltage.

Motor Induced Voltage: Ec=Ke×N
Ec: Motor induced voltage, Ke: Power generation constant, N: Rotation rate
The motor induced voltage Ec is equal to the power generation constant Ke multiplied by the rotation rate N. Hence the induced voltage of the motor is proportional to the rotation rate.

Motor Torque: T=Kt×Ia
T: Torque, Kt: Torque constant, Ia: Motor current
The motor torque T is the torque constant Kt multiplied by the motor current Ia. Hence the motor torque is proportional to the current.

Relationship between Rotation Rate and Torque: N=Ea/Ke-R/(Ke×Kt)×T
The above-described equations for the induced voltage and torque of a motor are summarized, and the relationship between rotation rate N and torque T is illustrated below. Ke and Kt are constants, and so from the equations we can see that: 1) when a torque T is applied, the rotation rate N drops by a fixed amount; and, 2) when the torque T is a fixed value, the rotation rate N rises in proportion to the power supply voltage Ea.
The torque-rotation rate (T-N) characteristic is such that when a torque is applied, the rotation rate falls by a fixed amount, that is, the relationship is inverse proportionality. And, when the power supply voltage is raised, the voltage applied to the motor rises, so that the rotation rate increases. The maximum torque occurs when the rotation rate is zero.
The torque-current (T-I) characteristic indicates that when a torque is applied, the motor current increases by a constant amount, that is, increases proportionally. At maximum torque, which occurs at zero rotation rate, the motor current is maximum.
When driving a motor, the driving conditions must be considered based on these relationships.

Benefits of Brushed DC Motor

Simplicity

Brushed DC Motors have simple and effective speed and torque control. Simply controlling the voltage and current gives you control over the speed and torque, respectively. They are relatively simple in construction, comprising fewer parts compared to other motor types, making them easier to understand and maintain.

Cost-Effective

Because of their simplicity in design and control, Brushed DC Motors are generally more cost-effective, especially for low-volume or single-unit applications. Brushed DC motors are often less expensive to manufacture and repair, making them cost-effective for various applications.

High Starting Torque

These motors provide a high starting torque, which is a crucial feature for applications that require a significant amount of force to start. These motors offer straightforward speed and torque control through adjustments in voltage or current, making them suitable for many basic applications.

Compatibility with Battery Power

They can efficiently operate on battery power sources, making them ideal for portable devices and applications requiring mobility. Brushed DC motors are widely available in various sizes and configurations, making them accessible for a range of applications from small devices to larger machinery.

Types of Brushed DC Motor

Permanent Magnet Types

Permanent magnet brush DC motor is the most favorite among all brushed DC motors. This applies stable magnet to generate the magnetic field in the stator. This magnetic field is needed to operate the motor. The response to the change of input voltage of this motor is quite good. The speed of motor is easily controllable.

Shunt-Wound Types

The shunt-wound brushed DC motor is made with the parallel connection between field coil and the rotor. Thus, stable torque at less speed can be easily generated by using this motor. This kind of motor is perfect in industrial and automotive uses with rigid speed control conditions.

Series-Wound Types

The shunt-wound brush DC motor is made with the series connection between field coil and the rotor. The electric current in the stator and rotor is gained under load condition which makes them perfect for high-torque uses such as cranes and winches.

Applications of Brushed DC Motor

Industrial Automation

Brushed DC motor power conveyor systems, robotic arms, and CNC machines offer precise control and reliability crucial for automation.

Transportation

Electric vehicles (EVs) rely on a brushed DC motor for propulsion. The simplicity and efficiency of these motors contribute to the success of EVs.

Consumer Electronics

Household appliances like fans, blenders, and hard disk drives incorporate the brushed DC motor for their compact size and efficient performance.

Renewable Energy

The brushed DC motor drives renewable energy systems such as wind turbines and solar tracking mechanisms, harnessing clean energy sources.

Medical Devices

The brushed DC motor plays a pivotal role in medical equipment like MRI machines, where precision and control are paramount.

Components of Brushed DC Motor

Stator

The stator as you may know is the stationary part of the engine and generates a stationary magnetic field around the rotor. This magnetic field is generated by either permanent magnets or electromagnetic windings. The construction of the stator or the way the electromagnetic windings are connected to the power source defines the different types of this motor.

Rotor

The rotor, aka “armature,” is constructed of one or more windings. When these windings are turning they produce a magnetic field. The poles of this magnetic field will face to the opposite poles generated by the stator and make the rotor to turn. The windings are constantly being energized in various sequences when the motor turns so that the magnetic poles generated by the rotor do not interrupt the poles generated in the stator. We call this switching between the field in the rotor windings commutation.

Brushes and Commutator

Unlike other electric motor types such as brushless DC and AC induction motors, BDC motors do not need a controller to alternate current in the motor windings. Instead, the change of the windings of a BDC motor is accomplished entirely mechanically. The commutator, a segmented copper sleeve, is set on the axle of a BDC motor.As the motor rotates, carbon brushes slide over the commutator and make contact with different segments of the commutator. These segments are connected to different rotor windings, thus, a dynamic magnetic field is generated inside the motor when a voltage is applied across the brushes.

Difference between Brushed and Brushless DC Motors

Brushed DC Motors
A brushed DC motor has permanent magnets inside its outer body with a rotating armature inside. The permanent magnets are stationary and are called the 'stator'. The rotating armature contains an electromagnet and is called the 'rotor'. In a brushed DC motor, the rotor spins 180-degrees when an electric current is applied to the armature. In order to travel beyond the initial 180 degrees, the poles of the electromagnet must flip. Carbon brushes contact the stator as the rotor spins, flipping the magnetic field and enabling the rotor to spin 360-degrees.

Advantages
1.High Starting Torque: For applications that need to get up to speed really quickly, a high-torque brushed electric motor is the choice for you. For example, in applications such as caravan movers, a high starting torque is essential.
2.Low Cost: Brushed DC motors are relatively inexpensive to produce and purchase compared to brushless DC motors.
3.Suited to Industrial Environments: Due to their high starting torque, brushed motors are also a popular choice in industrial environments.

Disadvantages
1.Risk of Increased Maintenance: Due to the effects of friction on a motor's carbon brushes, they will naturally wear over time. As a result, brushed electric motors are more likely to require some sort of maintenance in the form of brush cleaning or replacement.
2.Lower Speed: Despite a high starting torque, brushed motors are not as capable of maintaining high-level speeds. This is because running a brushed motor at a consistent high speed can cause it to get warm.

Brushless DC Motors
Like a brushed motor, a brushless motor works by alternating the polarity of windings inside the motor. It is essentially an inside out brushed motor, which eliminates the need for brushes. In a brushless DC motor, the permanent magnets are fitted to the rotor, with the electromagnets on the stator. An electronic speed controller (ESC) regulates or 'commutates' the charge to the electromagnets in the stator, to enable the rotor to travel through 360-degrees.

Advantages
1.Long Lifespan: Brushless DC motors don't have brushes, which means they require less maintenance than their brushed counterparts.
2.Efficiency: The lack of brushes means that no speed is lost, making brushless DC motors a little more efficient, typically 85-90% compared with their brushed counterparts at a typical 75-80% efficiency.
3.Quiet Operation: Due to the lack of brushes, brushless motors run extremely quietly and have particularly smooth operation. This is especially useful for applications that require such properties, such as patient hoists.

Disadvantages
1.Requires a Controller: Brushless DC motors need to be wired to an electronic speed control (ESC), to enable current to flow to the electromagnets.
2.Cost: Due to the requirement for a controller, brushless DC motors can be more expensive.

Maintenance Tips for Brushed DC Motor

Because DC motors rely on brushes and many problems can arise from the brushes, maintenance should be conducted on a regular basis to check on the condition of your motors. By regularly examining your commutators, you can prolong the life of your DC motors by preventing any long term damaging problems or catastrophic failures. It is always smart to have spare brushes for your motors in case you need to replace your brushes due to wear and tear or contamination.

DC Motor Brush Problem: Threading

Threading results in fine lines on the surface of your commutator. The fine lines occur when copper is transferred from the commutator to the brushes. The copper becomes embedded in the surface of the brush and scratches the surface of the commutator. Threading can be caused by low brush pressure, contamination, or using the wrong type of brush. If there is evidence of threading, you must clean the commutator, clean or replace the brushes, and install the brushes with the proper tension.

DC Motor Brush Problem: Grooving

Grooving leaves a smooth, slotted area on your commutators. Common causes of grooving include using the wrong brush grade, a brush with impurities, or contamination. When grooving is present, examine the type of brush used for grade and contamination. Replace or clean the brushes as necessary.

DC Motor Brush Problem: Copper Drag

Copper Drag is when copper particles are dragged to the segment edges of a commutator and is typically caused by brushes with too little tension, excessive vibration, or by an abrasive brush. It’s important to address copper drag immediately because the buildup of copper in the commutator segments can lead to a short circuit of the armature windings. The commutator should be cleaned of the copper flakes and the brushes should be examined for proper grade.

DC Motor Brush Problem: Flashover

Flashover is a short circuit between the brushes of a motor. The short circuit is caused by a buildup of dirt, copper particles, and debris between commutator segments. The segments are then shorted together resulting in arcing between the brushes. A flashover can be catastrophic to the motor and motor brushes. If a flashover occurs, the motor must be cleaned of all contaminates, the surface of the commutator cleaned or repaired, and the brushes will need to be inspected.

Factors to Consider When Selecting Brushed DC Motor

Input Power

Take a note of the available input voltage at the terminal of the motor, current limits, and what controls will be required to manage the motor within the application. Pay close attention to the maximum allowable current early in your selection process. This is often overlooked until the testing phase when failures can occur.n The current and efficiency of the motor can be changed by the style of the gearbox, input power, or other factors. Using a more efficient gearbox means you draw less current to run the motor. The measure of available voltage is a key criterion in the selection of brushed DC motors. Most devices today are portable and battery-operated. DC motors of various sizes and capacities can operate in the range of 6V to 220V. Hence, the amount of available as well as required power must be considered when selecting a DC motor.

Motor Size

Technological development in the modern world is focused on reducing the footprint of machines. Most of the devices around us are rapidly shrinking in size. It is vital that the motor fits the available size within the device. Even as the size is being reduced, motors must deliver the best possible efficiency. Here, the power consumption of the motor also comes into the picture. Diameter of the motor is in square proportion to the torque and length of the motor is in linear proportion to the torque.

Torque and Speed

The torque and speed of the motor have a bearing on the motor frame size. If the size of the motor is small, it will deliver lower torque. If higher torque is required, larger housing for the motor is an important requirement. For instance, rolling an automobile window will require a smaller motor whereas rotating the magnets of MRI scan will need a far bigger one. Assuming that the voltage stays the same, the torque of the DC motor is inversely proportional to the speed. This connection is based on the slope of the speed/torque curve.

Duty Cycle

The motor duty cycle is critical to determining the motor type as well as the service life of the motor in use. Operating time, dwell time, and rotational direction are key aspects of the brushed DC motor duty cycle. In the case of most industrial applications, motors are operated intermittently as it helps extend the service life of the motors. The duty cycle is also influenced by the motor size. If the motor needs to run periodically, a shorter motor would be able to introduce as much power as a larger motor running continuously. This is because the off-time for the intermittent duty motor allows for the release of excess heat. If used in this manner, smaller motors can be used for a long duration without depleting the positive characteristics of the machine itself.

Working Conditions

Particle ingress and temperature are two major environmental constraints impacting motor performance. Most standard motors are built to operate in a clean, dry room temperature environment. However, in areas such as solar energy or defense, motors must operate amidst temperature extremes, dust, or corrosive environments. In such cases, a specially constructed motor should be considered. IP ratings provide an industry-wide understanding of a motor’s protection against dust and water. The same is the case with temperature class ratings. For every 10 degrees of temperature your application exceeds the maximum temperature rating, the motor life is reduced by 50%.

Certifications

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Our Factory

Changzhou Duowei Electric Co.,Ltd. was founded in 1997 and has more than 200 employees. It has developed hundreds of different product applications and established extensive strategic partnerships around the world with these products. Duowei Electric, the manufacturer of Wit Motors, our company does not use "conflict minerals", and the broad service industries include: automotive, industrial automation, robotics, household equipment, medical equipment, HVAC systems, office equipment, defense and aerospace, Electrical equipment and power tools.

Ultimate FAQ Guide to Brushed DC Motor

Q: Do Brush Motors Have More Torque?

A: Brush motors can perform well when providing an initial torque, but they usually fall short when great torque is required, because their commutation system is so simple. Hence, brush friction increases as speed increases and viable torque decreases. In this case, they are less efficient in comparison with brushless DC motors.

Q: How to Make A Brushed Motor Faster?

A: By adjusting the operating voltage or the intensity of the magnetic field in the Brushed DC Electric Motor, using brushed motor driver, the speed and torque may be adjusted to give a constant speed or a speed that is inversely proportional to the mechanical load. (The controller sends current pulses to the motor windings, which govern the motor’s speed and torque.)

Q: Where do brush dc motors are used?

A: Brush dc motors, on the other hand, provide high peak torques and may be driven by simple speed controllers to move a wide range of applications. They are frequently less expensive than alternative options, especially in big quantities. They can also have a linear torque-speed connection, which simplifies control.

Q: When to use a brushed motor?

A: Brushed motors do not need additional electronics to run. Hence, they offer a plug-and-play option. The lack of electronics saves considerable costs. Brushed motors can work with gearheads, and their lifespan is not affected by the same. Both the motor and the gearhead are mechanical components that witness a high degree of wear and tear. They offer high starting torque.

Q: What is the use of brush in DC motor?

A: A carbon brush is a critical part of a dc motor, which relies on the brush for the transmission of electrical current coming from the machine's rotating part. The brush is also responsible for changing the course of current in the conductors during the rotation process.

Q: How do I know if my DC motor is brushed?

A: If there's two heavy wires, with or without light ones, it's a brushed DC motor. If there's light wires, too, then chances are the motor has some feedback built in; either a tacho-generator (gives a voltage proportional to motor speed) or a shaft encoder of some sort.

Q: How long do brushed DC motors last?

A: Brushed motor life is limited by the brush type and can attain 1,000 to 3,000 hours on average, while brushless motors can attain tens of thousands of hours on average, as there are no brushes to wear.

Q: What happens when DC motor brushes wear out?

A: Once the carbon brushes are completely worn the motor will begin to underperform before failing – running a motor with worn carbon brushes can result in extensive damage to the motor.

Q: How long should motor brushes last?

A: Carbon brushes will on average last between 1 and 5 years in most power tools but this is all dependant on how much they are used in number of hours, the more daily use the power tool has the quicker it will wear over a certain period of time.

Q: How do you control a brushed DC motor?

A: Brushed motors generally operate at low speed and can be driven by a simple pulse width modulation (PWM) controller to vary the voltage supplied to the motor to control the speed in one direction and provide the torque for the motor drive.

Q: How can I make my brushed motor quieter?

A: Capacitors are usually the most effective way to suppress motor noise, and as such we recommend you always solder at least one capacitor across your motor terminals. Typically you will want to use anywhere from one to three 0.1 µF ceramic capacitors, soldered as close to the motor casing as possible.

Q: How can I slow down a DC motor?

A: If you want to go really slow, the resistor method will probably cause the motor to stall way before you reach your desired RPM. Using PWM ensures you get pulses of full torque, which allows you to drive the motor to really slow speeds. Yes, using resistors were the first method of controlling motor speed.

Q: What causes a DC motor to run too fast?

A: For a dc motor, speed is proportional to back emf / field flux. If you reduce the field-flux of an already running motor, its speed increases. If you reduce it to a very low value, the speed becomes dangerously high.

Q: Are brushed DC motors efficient?

A: Yes, although not as efficient as brushless motors. Brushless motors are typically 85-90% efficient whereas brushed DC motors are around 75-80% efficient.

Q: Do brushed DC motors require regular maintenance?

A: Yes, they require periodic maintenance due to brush wear, but maintenance is generally simpler compared to other motor types. Many brushed motors – especially large ones – have replaceable brushes, typically made of carbon, which are designed to maintain good contact as the wear. These motors require periodic maintenance. Even with replaceable brushes, eventually the commutator also wears to the point that the motor must be replaced.

Q: Do brushed DC motors generate heat?

A: In a DC motor with a mechanical commutator and brushes, the copper windings are wound in slots around the “rotating” part of the motor (called the armature). The heat generated by the copper windings on the armature will conduct through the armature laminations and to the motor shaft and bearing system.

Q: Can brushed DC motors be used with variable power sources like batteries?

A: Yes, they are compatible with variable power sources, making them suitable for battery-operated devices. In case of brushed DC motor, however, operation directly from a voltage source or battery is possible too. If the voltage is adjustable, the speed can also be varied.

Q: How does the efficiency of brushed DC motors change with load?

A: Trivially, at zero load, the efficiency is zero. At very high load, we also know that the losses increase as current squared, while the torque varies as the current, and as the speed drops at high loads, the power output increases less than linearly with current, so the efficiency also drops.

Q: How to drive brushed DC motors?

A: To drive a brushed motor, DC voltage is applied across the brushes, which passes current through the rotor windings to make the motor spin. In cases where rotation is only needed in one direction, and speed or torque doesn't need to be controlled, no drive electronics at all are required for a brushed motor.

Q: When should I replace my DC motor brushes?

A: Generally, if the brush is worn down to 1/4th of its original length, it is time for replacement. If you need to replace your brushes make sure that the brush is the correct dimensions, type and grade for the motor. Typically you can find this information in your motor's manual.

Q: What is a brush DC motor?

A: A Brush DC Motor provides precision control of speed, driven by a direct current. Noted for a particularly high ratio of torque to inertia, the Brush DC Motor has the potential to supply three to four times more torque than its rated torque. If needed, it can even provide up to five times more, without stalling. The Brush DC Motor consists of six different components: the axle, armature/rotor, commutator, stator, magnets, and brushes. The Brush DC Motor offers stable and continuous current, using rings to power a magnetic drive that operates the motor's armature. Perhaps one of the earliest used motors, the Brush DC Motor is commonly used because of the ability to vary the speed-torque ratio in almost any way.

Q: What are carbon brushes in brush DC motor?

A: A key component of the Brush DC Motor is a device known as a carbon brush, which conducts current between stationary wires and moving parts. For a Brush DC Motor to work, the coils of the Brush DC Motor rotor must be connected to complete an actual circuit. To do this, slip rings are affixed to the shaft of the Brush DC Motor, and brushes are attached to the rings, which will be used to conduct the current. Carbon brushes are considered to be both the most critical, yet weakest point of the Brush DC Motor. This is because they are highly susceptible to wear, especially when running the Brush DC Motor outside of its parameters. The wearing of carbon brushes acts as a disadvantage to the Brush DC Motor, however they can be easily replaced. Although many people consider carbon brushes in a Brush DC Motor to be a "Black Art," they still serve a great purpose when operated in the proper conditions. They tend to yield an excellent life, and perform an amazing function for your Brush DC Motor.

Q: What are physical properties of a brush DC motor?

A: A typical Brush DC Motor contains six components: Stator, Rotor/Armature, Commutator, and Brushes, an axle, and magnets. The stator surrounds the rotor, and generates a magnetic field by means of electromagnetic windings or permanent magnets. The rotor can also be called the armature. It consists of one or more windings that produce a magnetic field when energized, causing the motor to turn. The commutator is a copper sleeve that is located on the rotor's axis. This performs mechanical commutation of the windings, eliminating the need for a controller to switch the current. The brushes located inside the Brush DC Motor generate a charge by rubbing the different parts of the commutator. It is because of this rubbing, that the brushes and commutator are prone to wear.

Q: What are the components of brushed DC motors?

A: Stator

The stator consists of the central and cylindrical two-pole permanent magnet, the core that supports the bearings, and the steel tube that closes the magnetic circuit. High-quality rare earth magnets ensure outstanding performance in a small envelope. Sintered bearings and ball bearings are available depending on your application loads and requirements.

Brush holder endcap

The brush holder endcap is made of a plastic material. Depending on the intended use of the motor, the brush could be of two different types; carbon or multi-wire. Carbon types use copper graphite or silver graphite and perfectly suit incremental motion applications where high continuous and peak torque are required. Multi-wire type uses precious metal and will guarantee low starting voltage and improved efficiency, a perfect match for portable battery-powered applications. Portescap's engineer can design endcaps that reduce electromagnetic noise to meet EMC requirements.

Rotor

The rotor is the heart of DC motor. The coil is directly and continuously wound onto a cylindrical support that is later removed, eliminating excessive air gaps and inactive coil heads that bring no contribution to the torque creation. The self-supporting coil does not require an iron structure and therefore offers low moment of inertia and no cogging (the rotor will stop in any position). Unlike other conventional DC coil technologies, due to the absence of iron there are no hysteresis, eddy current losses or magnetic saturation. The motor has a perfectly linear speed-torque behavior and the running speed depends only on supply voltage and load torque. The brushes/collectors combination is optimized to withstand a long operational lifetime at up to 12,000 rpm and provide high reliability.

As one of the leading brushed dc motor manufacturers and suppliers in China, we warmly welcome you to wholesale high-grade brushed dc motor for sale here from our factory. All custom products made in China are with high quality and competitive price. Contact us for OEM service.

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