Top-Rated Low RPM BLDC Motor Manufacturer in China

Longbank concentrates on manufacturing all models of low rpm BLDC motors. We are capable to produce over 50 000 sets of motors. Without question, we can satisfy your low rpm BLDC motor requirements!

Here, you can get dependable quality and great performance low rpm BLDC motor!

Low RPM BLDC Motor

As an expert manufacturer since 1972, we have been providing the best quality low rpm BLDC motor. All our products have undertaken various testings through our own product and material testing centers. When you choose Longbank, we ensure that your low rpm BLDC motors are environmentally friendly and safe to use. You can choose from our wide selection of low rpm BLDC motor that fits your application.

About Longbank Motor

Longbank Motor has spent over 20 years in the industry. We are focusing on manufacturing and supplying small motors for various usage such as cars, home appliances, etc. Here in Longbank, we have a powerful R&D team to guarantee high-performance motor solutions.

We have received certifications that prove our reliability and trustworthiness. We have met ISO14001-2004, ISO9001:2008, SGS, CE, and more. Longbank, since started, has kept promoting efficient production, superior services, and quality products.

Brushless DC Motor manufacturer

Low RPM BLDC Motor Manufacturing Expert

electrical motor manufacturing in factory
custom electrical motor factory

Longbank has full dedication to supplying customers with our boundless range of low rpm BLDC motors. Since then, over 20 years ago until today, we have kept on offering efficient, high-performance, and dependable low rpm BLDC motors.

Throughout the years, we have earned credibility and a good image in the international market. Also, we establish strong business relationships with thousands of customers worldwide. Let us handle your next low rpm BLDC motors requirements!

More About Longbank Low RPM BLDC Motor

For more certifcation and patent, you can check here.

Longbank Low RPM BLDC Motor

Longbank is your exceptional source of low rpm BLDC motor in China. We were first founded in 1972, specializing in manufacturing small motors, including low rpm BLDC motors. Being an expert manufacturer, Longbank aims to boost your business through our superior products.

We use our advanced assembly and production lines, our full range of testing equipment, and innovative technology to develop your ideal low rpm BLDC motors.

Longbank Low RPM BLDC Motor Features:

  • Constant rotating speed
  • Power-dense solution
  • Efficient and noiseless
  • Low maintenance
  • High speed & high efficiency

We make sure to develop a low rpm BLDC motor with complete features and expected qualities. We can make it as you require. Longbank will always be at your service whether you require a standard or custom low rpm BLDC motor for any application.

Throughout many years of experience, Longbank specifically designed low rpm BLDC motor to move heavy equipment and parts at a slower rate. By providing a lot of torque or power at a lower speed, moving weighty and large objects will be possible. It can move gates, lifts, and doors in a more controlled manner.

Due to quality, Longbank low rpm BLDC motor serves linear motor transport systems, power tools, garden, and home appliance uses. Home appliance application includes the following:

  • Vending machine
  • Electric fan
  • Fish automatic feeder
  • Card dispenser
  • Electric door-lock
  • Financial apparatus
  • Massager machine
  • Hair rollers
  • Printer

We provide any model of low rpm BLDC motor to suit different applications. All models are guaranteed high-quality for your satisfaction. We deliver your small motor orders on time, especially when it comes to low rpm BLDC motors. Delivery time depends on the quantity you order.

Choose Longbank as your top low rpm BLDC motor supplier. Whether you need a low rpm BLDC motor for your business or your equipment, Longbank highly presents our great selection. All models met the ISO14001-2004 and ISO9001:2008.

Longbank has full capabilities, make us confident to provide your ideal low rpm BLDC motor even in peak season.

Book your next orders of Low RPM BLDC motor today!

Low RPM BLDC Motor: The Ultimate FAQ Guide

A low rpm BLDC motor is essentially a synchronous DC motor that consists of a rotor and stator and is powered by direct current (DC).

It is designed to convert electrical energy into mechanical energy for low-speed applications.

In this guide, you’ll understand numerous aspects surrounding this type of motor to give you a broad idea of its fundamentals.

Eventually, it becomes easier for you to make the right choices, especially when buying and using this type of motor.

How Slow Can Low Rpm BLDC Motor Run Continuously?

Figure 1 Low RPM BLDC Motor

It depends entirely on the controller, which is responsible for adjusting the coil current direction depending on rotor direction.

Ordinarily, you can always operate this motor as a stepper motor to enable it to work as slowly as you wish.

Of course, this means that attaining smooth operation would be relatively difficult, and you’ll also need to consider the motor cooling.

At low speed, little torque is usually required; thus, maintaining the operation at low speed will require algorithms and feedback hardware.

In some applications, this motor can operate below 1/3 of its rated speed, but it may not be advisable unless for a short duration.

Primarily, thermal limitations often inhibit low-speed operating time in some applications, which affects the torque at rated speed.

However, in different applications, such as electric cars, you can attain slow speeds as long as you use the right controller design.

In such instances, thermal limitations wouldn’t necessarily be as severe as with applications such as fan and propeller.

How Do You Control The Speed Of Low Rpm BLDC Motor?

Ideally, speed control in a low rpm BLDC motor is critical in operating at the desired rate.

You can always control speed of this device by regulating the input DC voltage.

Often, the lower the voltage, the less the speed, and vice versa.

Several control algorithms have been used to provide speed control in these motors.

Such algorithms must provide voltage to control motor speed, system to commutate motor, and technique for estimating rotor position using hall sensors.

Low rpm BLDC motor use control method known as trapezoidal commutation.

Current in, this scheme is controlled through motor terminals, each pair at a time.

While at it, the third motor terminal remains electrically disconnected from the power source.

Can You Use Low Rpm BLDC Motor As A Stepper Motor?

Yes.

Technically, the working principle of stepper motor is more or less similar to that of a low rpm BLDC motor.

The main difference is the former moves in relatively smaller steps.

Hence, you can easily use a low rpm BLDC motor as a stepper motor and still attain the efficiency and desired results.

Does Low Rpm BLDC Motor Have More Torque?

Yes.

Low rpm BLDC motor guarantees a higher torque to weight ratio.

Usually, these motors do not have brushes that get worn out.

As such, they have immense efficiency and performance with lower susceptibility to mechanical tear and wear.

Therefore, they provide increased torque per watt of power input, which translates to enhanced efficiency.

How Do You Commutate Low Rpm BLDC Motor?

Figure 2 BLDC motor commutation

Commutation of this motor is attained by determining the angular position and applying current to the stator.

Subsequently, this creates a magnetic field that attracts rotor to the new position.

For example, when you start at the beginning of the timing diagram, the hall switches would read; 1 and 3 on, and 2 off.

Hence, the motor controller interpreting this easily applies positive current into phase 1 lead.

Consequently, the current returns to controller through phase 2 lead.

This makes the rotor rotate and trigger the hall switches to change to; 1 on, 2 off, and 3 off.

Nevertheless, current would still flow into phase 1 and instead returns through phase 3.

The sequence continues through the following four states and restarts at the first to provide a constant rotation.

Does Low Rpm BLDC Motor Spin Freely?

Ideally, this motor should always spin freely when all wires are separated since there would be an incomplete circuit.

This motor uses electromagnets to spin the motor by pulling and pushing magnets connected to the bell.

However, if you short any of the two wires together, it will create resistance within the motor when you attempt to spin it.

Thus, if the motor resists the rotation irrespective of wire connections, chances are high it has an internal short circuit.

Can You Increase Or Decrease Speed Of Low Rpm BLDC Motor?

Yes.

The general approach of increasing speed of low rpm BLDC motor is by increasing the frequency and vice versa.

For instance, if the motor rating is 460 volts with a base frequency of 60 Hz, you can easily run it at 230 volts and 30 Hz.

Thus, it means the motor will rotate at half speed.

And if the motor base is 60 Hz, raising the frequency to 120 Hz implies motor speed will double.

How Do You Increase Torque Of Low Rpm BLDC Motor?

The most suitable approach to increasing torque in this motor is by using stronger magnets.

Ordinarily, torque constant is dependent on magnetic circuit.

Thus, the primary objective design construction of this motor is to enable the maximum flux generated by a magnet to go through winding.

Therefore, the stronger the magnet used in the motor, the higher the torque.

What Is A Hall Sensor In Low Rpm BLDC Motor And Why Is It Important?

Figure 3 Hall sensor in BLDC Motor

Hall sensor is an electronic device designed to detect magnetic field’s presence and magnitude using Hall Effect.

This sensor converts its findings into electronic data, providing a measurement of a varying magnetic field.

Essentially, the hall sensor indicates the magnitude and presence of a magnetic field close to a conductor.

This sensing switch outputs a logic depending on magnetic field detection.

These sensors are important in low rpm BLDC motors because they detect variables like displacement, proximity, and speed of the motor.

They are non-contact thus can produce either digital or analog signals based on the design and intended function.

Besides, they are economical, permanent, and easy to install inside the motor.

What Determines The Rpm Of A Low Rpm BLDC Motor?

Speed in low rpm BLDC motor is directly proportional to the applied voltage.

When the motor is set up for constant power, the speed will be inversely proportional to torque or rotor shaft.

In essence, the current that flows through the windings is directly proportional to torque.

Simply put, speed of this motor increases with any increase in voltage.

What Is The Difference Between Low Rpm BLDC Motor And Brushed Motor?

In the recent past, low rpm BLDC motors have become quite popular in the market for several applications.

Brushed DC motors have also been available for a while.

These two types of motors, however, differ on a wide range of features such as the following;

  • Longevity – Low rpm BLDC motor exhibits a longer service lifespan since it does not have brushes that wear out easily. Brushed motor, on the other hand, tends to have a shorter lifespan since the brushes seemingly wear out faster.

 

  • Rotor inertia – In a low rpm BLDC motor, the rotor inertia is low since it has permanent magnets that enhance dynamic response. Brushed motor has higher rotor inertia that seems to inhibit the dynamic characteristics.

 

  • Speed/torque features – It is flat in low rpm BLDC motor, allowing operation at all speeds with rated load. In a brushed motor, the speed characteristics are moderately flat, reducing torque at higher speeds since brush friction increases.

 

  • Speed range – Low rpm BLDC motor has a higher speed range; thus, no mechanical inhibition is imposed by brushes. On the other hand, speed range in a brushed motor is lower due to mechanical limitations by the brushes.

 

  • Commutation – Low rpm BLDC motor features electronic commutation depending on hall position sensors. Brushed motor, however, features brushed commutation.

 

  • Output power – In a low rpm BLDC motor, the output power is high due to its superior thermal characteristics. On the other hand, brushed motor has moderate output power since the heat produced by armature is dissipated in the air.

 

  • Cost – The cost of building a low rpm BLDC motor is relatively high since the permanent magnets are quite expensive. Building brushed motor, in contrast, is comparatively low.

 

  • Control needs – Low rpm BLDC always requires a controller to keep the motor running and for determining variable speed control. On the other hand, a brushed motor hardly requires a controller unless in instances where variable speed is desired.

How Does Low Rpm BLDC Motor Function?

The working principle of this motor is quite straightforward.

Essentially, every commutation sequence has one of the windings energized to positive power.

The second winding is negative, while the third stays in non-energized conditions.

Torque is produced as a result of interaction between permanent magnets and a magnetic field generated by stator coils.

When these two fields are at 90° to one another and fall off as the fields move together is when peak torque occurs.

To keep the low rpm BLDC motor running, the magnetic field produced by the windings must shift position as rotor moves to draw near with stator field.

What Are The Advantages Of Low Rpm BLDC Motor?

This motor presents several benefits when used in different applications.

Ideally, some of the notable advantages of using this motor include the following;

  • Increases runtime

In modern-day trade, increased runtime is quite important since battery power in most instruments hardly generates wastage energy like friction and heat.

Hence, more power goes to your specific application.

As such, battery will have an extended period and allow you to do the job than it would do with a brushed motor.

  • Low maintenance

Typical low rpm BLDC requires low to no maintenance since it does not have components that require frequent check-ups or replacement.

Of course, this is imperative since it gives you peace of mind knowing performance and efficiency is guaranteed throughout its service lifespan.

  • Guarantees reliability

Since this motor does not have brushes, it means issues related to commutator are avoided.

Besides, absence of brushes in this motor also enables the motor to run efficiently since the speed is not inhibited.

  • Guarantees longevity of your tool life

There is an immense reduction in heat and friction in this motor since it does not have brushes.

Of course, this is fundamental since it prolongs your tool life significantly.

Since there are no brushes in this motor, you will rarely need to purchase another machine, and in the long run, you save money.

  • Quiet

Low rpm BLDC motor is super-quiet since it does not have brushes, which may come in contact with one another when it is running.

Hence, it is a suitable consideration, especially for many applications where silence is crucial such as air conditioners.

  • Smaller and lightweight

This motor is generally smaller and more lightweight compared to brush motor.

Therefore, most equipment manufacturers prefer it for making lightweight models that are portable and easy to handle when working.

  • Easy to control

Low rpm BLDC motor is highly controllable since it uses a feedback mechanism to provide precise torque and speed characteristics.

It is this precision control that allows it to reduce energy consumption and heat generation.

What Are The Types Of Low Rpm BLDC Motor Available In The Market?

Ordinarily, low rpm BLDC motor is categorized into different types based on two main elements as follows;

Figure 4 Structure of BLDC Motor

  • Physical design

In this aspect, this motor comes in two types;

  • Inner rotor design-It features a conventional design with the rotor located at the center and stator coil winding through it.

 

  • Outer rotor design– In this configuration, the stator windings are positioned at the center, whereas the rotor with permanent magnets surrounds the stator.

 

  • Sensors

Here are the types of low rpm BLDC motor based on this element;

  • Sensor-based motor– This motor exhibits higher precision and is often used in specific applications. It is also relatively costly.

 

  • Sensorless motor– It is usually available in three variants; single-phase, two-phase, and three-phase. Three-phase is seemingly the popular one.

How Does Low Rpm BLDC Motor Compare With Induction Motor?

These two types of motor compared on the following grounds;

  • Rotor inertia– Low rpm BLDC motor has low rotor inertia hence better dynamic characteristics. Induction motor, on the other hand, has high rotor inertia, thus relatively poor dynamic characteristics.

 

  • Torque characteristics– In low rpm BLDC motor, torque characteristics are flat, allowing operation at all speeds with rated load. Induction motors have nonlinear torque characteristics that lower torque at lower speeds.

 

  • Slip– There is no slip experienced in low rpm BLDC motor between its rotor and stator frequencies. However, in induction motor, rotor runs at a relatively low frequency than stator by slip frequency. Moreover, slip here increases with load on the motor.

 

  • Starting current– In a low rpm BLDC motor, starting current is rated; thus, no special starter circuit is required. In an induction motor, starting current is up to about seven times rated hence the need for selecting circuit rating carefully.

 

  • Controller needs– Controller is required in a low rpm BLDC motor to keep the motor running and determine variable speed control. On the other hand, an induction motor hardly requires a controller for fixed speeds.

What Is Back EMF In Low Rpm BLDC Motor?

It is a voltage generated by each winding when low rpm BLDC motor rotates.

This voltage opposes the main voltage supplied to windings according to Lenz’s law.

Polarity of back EMF is in the opposite direction of energized voltage, and it often depends on the following three factors;

  • Rotor angular velocity
  • Number of rotations in stator windings
  • Magnetic field generated by rotor magnets

How Do You Select Ideal Low Rpm BLDC Motor Rating For Your Application?

Ideally, determining the suitable motor rating for your application is indispensable.

You need to select the motor with a proper rating based on the load characteristics.

The parameters which govern motor selection for a particular application include the following;

  • RMS torque needed

Root mean square (RMS) torque is the average continuous torque needed for the specific application.

It is dependent on many factors such as frictional torque, load torque, peak torque, run times, acceleration, and deceleration among others.

  • Operating speed range

It is the motor speed needed to drive the application and is usually determined by type of application.

Ordinarily, a relatively high operating speed can be accounted for components of trapezoidal speed angle.

It leads to an average speed that is equal to speed movement.

  • Peak torque

You can determine the maximum torque required for the application by getting the sum of load torque, torque due to inertia, and torque needed to overcome friction.

Different factors will contribute to overall peak demands

Is The MOQ When Buying Low Rpm BLDC Motor?

Yes.

But it always depends on the specific company you are purchasing from.

Some manufacturers have a higher MOQ, whereas others have a relatively low MOQ.

Nevertheless, it is imperative always to inquire from your preferred company to determine the specific MOQ they offer for these units.

Even so, most manufacturers often provide a flexible MOQ, which makes it ideal for you to negotiate and arrive at a suitable quantity.

How Long Can Low Rpm BLDC Motor Last?

Ordinarily, it depends on many factors, including the power rating and the specific application of the motor.

Some motors can last for many tens of thousands of hours, especially those used in comparatively moderate applications.

But generally, the design construction of this device makes it possible to last longer than other types of motors.

Which Applications Use Low Rpm BLDC Motor?

You can use this motor in different applications across various sectors.

The common applications include the following;

  • Industrial robots
  • Computer hard drives
  • Simple belt-driven systems
  • Fans
  • Air conditioners
  • Blowers
  • Electric bicycles
  • Feed drives
  • CNC machine tools

What Is The Cost Of Buying Low Rpm BLDC Motor?

The price for purchasing this device usually varies based on several aspects, including the following;

  • Order quantity – Mostly, when you buy this device in bulk, you will likely get higher discounts than when you purchase a few pieces. Hence, bulk purchase makes it possible to attain cost-effective rates than buying a few units.

 

  • Capacity– Low rpm BLDC motors with higher capacities tend to be more expensive than those with lower capacities.

 

  • Brand– The Company you are buying from is also a significant determinant of buying price. Different manufacturers often tag different prices on these items depending on the model and brand popularity.

In essence, there is no definite cost for purchasing a low rpm BLDC motor.

It depends on different factors, including the few ones described herein.

Is Low Rpm BLDC Motor Repairable?

Yes.

However, in many instances, the type of repair is dependent on various factors.

You can replace some worn-out parts or the components on the verge of wearing out.

Majorly, the type of repair on this device usually depends on the specific fault it experiences.

Some faults are not necessarily repairable of they could be costlier than buying a new unit.

Hence, you need to inquire from a skilled professional to determine whether the particular fault is worth repairing.

What Are The Shortcomings Of Low Rpm BLDC Motor?

Some notable disadvantages of low rpm BLDC motor include the following;

  • Usually costlier than other types of motors
  • It has an electronic controller, which is always pricier
  • It requires a relatively complicated drive circuitry
  • Building this device is also expensive

Generally, the main disadvantages of this motor revolve around high cost in many aspects.

What Can Make Low Rpm BLDC Motor Fail?

This motor can fail due to many reasons, and the notable ones include the following;

  • Overheating– Excessive heat in the motor will destroy the windings and make it fail.

 

  • Poor handling– If you handle the motor aggressively and fail to take care of it accordingly, it will fail.

 

  • Exceeding operating range– Operating the motor beyond its limits is likely to make it fail. Thus, you need to note the thermal time constant of the winding when using this device to prevent you from operating it beyond its range.

 

Contact us for any inquiries of questions on low RPM BLDC motors.

The Ultimate FAQ Guide

If you have any questions about low-speed high torque BLDC motors, you will find the answer right here.

Whether you want to learn about the components, working principles, features, or specifications, this guide has all information you need.

Take a look.

What Is Low Speed High Torque BLDC Motors?

These are special synchronous motors that can operate at low speeds but still deliver high torque.

Remember, in motors, we refer to speed as rpm.

While torque is the rotational force the motor produces. The motor can do work.

Therefore, higher torque implies motor can do more work.

Figure 1 Low speed high torque motors

Where Can You Use Low Speed High Torque BLDC Motors?

Under normal circumstances, these motors’ design is such that they can handle heavy loads at a slow rate.

This way, these motors can move heavy objects.

The low-speed high torque BLDC motors do not require gearboxes to reduce the operating speed.

Therefore, you will bypass the gearbox in the entire design process.

In short, you can use these motors for automated systems or electrically controlled applications.

These may include cargo lifts, garage doors, emergency barriers, elevators, etc.

Should You Use Star Or Delta Winding For Low Speed High Torque BLDC Motors?

When designing stator winding of brushless DC motor high torque low rpm, you can consider either star or delta pattern.

If you wish to achieve high torque at a relatively low speed, you should go for stators wound in a star pattern.

Is Information About Poles Important When Choosing Low Speed High Torque BLDC Motors?

Yes, it is.

The BLDC motor rotor is a permanent magnet with North Pole and South Pole arranged alternating designs.

In most cases, the number of poles will determine where you will use the motor.

More poles in the BLDC motor will imply better torque. Remember, the torque of these motors depend on magnetic flux density.

Higher density implies the motor will have higher torque.

On the other hand, more poles will reduce the maximum speed of the BLDC motor.

It is also important to note that:

  • Iron losses will increase with an increase in poles
  • As poles increase in the BLDC motor, the transistor losses will also increase

In short, the number of poles also plays an integral role in low-speed high torque BLDC motors.

Again, since these motors do not have brushes, no power will be lost. Consequently, brushless motor high torque increases.

How Does Inner Rotor Design Compare To Outer Rotor Design In Brushless DC Motor High Torque Low RPM?

Inner rotor design and outer rotor designs are some of the most common options available in the market.

Here are some of the critical aspects you should know about this design:

Figure 2 Rotor design for BLDC

 

Outer Rotor Designs Of Brushless DC Motor

In this design, all the windings are in the core of the BLDC motor.

Here, the rotor’s magnets will act as an insulator, thus reducing the heat dissipation rate from the BLDC motor.

This design is known for lower rated current or low duty cycle in most cases. Of course, this is due to the location of stator windings.

The good thing about the outer rotor design of the brushless DC motor is the low clogging torque.

Inner Rotor Design Of Brushless DC Motor

Here, the stator winding surrounds the brushless Dc motor rotor.

They are basically on the BLDC motor casing.

The good thing about this design is its ability to dissipate heat effectively. Consequently, it improves its ability to produce high torque.

Additionally, these brushless motor designs have lower rotor inertia.

Which Are There The Parts Of Low Speed High Torque BLDC Motor?

Design and mode of operation play an integral role in the ability of the brushless DC motor to produce high torque at a lower speed.

Therefore, it is important to understand the general construction of the motor.

Some of the main components of these motors include:

Stator Of Low Speed High Torque BLDC Motor

Figure 3 Stator design for BLDC motor

The motor stator has laminated steel. They are stacked up to carry the windings.

Depending on the stator design, you can have a delta or star connection.

Normally, the star connection will give high torque at relatively low rpm.

This makes the star connection an important design parameter for the low speed high torque BLDC motors.

Of course, there are brushless motors with the stator in the delta connection. Delta connection is suitable for low-speed and low torque BLDC motors.

This is so because nearly 50% of the voltage is applied to a winding that is not driven. Thus, increasing the losses.

Another critical design parameter with the brushless DC motors is the slot.

You can have the steel laminations in the BLDC with or without slots.

Remember, even with the low speed high torque BLDC motors, the nature of the torque is very important.

Let’s look at the two designs.

Figure 4 Slotted vs slotless BLDC

Slotted Brushless DC Motor

Here, the stator has slotted steel laminations. Usually, they are stacked together alongside copper windings.

Normally, the copper windings are in the slots, called “teeth.”

Generally, these BLDC motors are inexpensive and simple to manufacture.

However, slotted BLDC motors have a clogging toque. This is common when the motor operates at low rpm.

Therefore, it implies that your low speed high torque BLDC motor will produce a jerky rotation or detent torque.

Slotless Brushless DC Motor

Here, we don’t have iron teeth.

These motors have steel rings in the stator lamination. The windings have resin encapsulating the windings.

This produces a rigid and better shape.

Of course, you will need a self-supporting winding between rotor and stator (air gap exists between the two).

As a result, this design produces better torque characteristics.

The torque is generally smooth, and you can easily control it.

However, slotless BLDC motors are more expensive.

Therefore, this is also an important design characteristic you should consider in the low speed brushless Dc motor.

Rotor Of Low Speed High Torque BLDC Motor

Figure 5 Parts of BLDC

The rotor is a permanent magnet.

The choice of material depends on the magnetic file density you need.

In these rotors, the number of rotors normally varies from 2 to 8.

Today’s rotors are made from rare earth alloys. They have so far replaced the ferrite magnets.

Although rotors made from ferrite materials are inexpensive, they have low magnetic flux density.

Therefore, for high torque, this material may not be appropriate.

On the other hand, rare earth alloys guarantee high magnetic density, hence high torque.

Additionally, you can also compress the rotor. Implying you can have a small rotor but still achieve high torque.

Hall Sensors In Low Speed High Torque BLDC Motors

Since the commutation of these motors is controlled electronically, you need hall sensors.

For sequential energizing of motor winding, you should know the position of the rotor.

The hall sensor on the stationary part of the motor will help determine the position of the rotor.

Figure 6 Hall sensors in BLDC

How Does Low Speed High Torque BLDC Motors Work?

It will be unfair to talk about the speed and torque of the BLDC motor without explaining how we generate these two parameters.

Of course, this is due to the interaction between a magnetic file of stator and rotor.

The maximum torque occurs when the two magnetic fields are at 90 degrees.

At any given instance, one winding energized to:

  1. Positive power
  2. Negative
  • Non energized condition

Implying once you power the wingding, it will get energized.

Once the hall sensors detect the position of the rotor, and the circuit energized, the interaction will cause the rotor to rotate.

Of course, this will produce both torque and speed.

But for the low speed high torque motors, you must keep the rpm low and torque high.

What Determines Brushless Motor High Torque?

Many factors affect the magnitude and nature of torque, and they include;

  • Number of poles
  • Design of the stator – slotted or slotless stator
  • The magnitude of the magnetic field/magnet strength
  • Nature of the rotor – type of material you use to make the permanent magnet
  • Distance between two opposing field
  • Supply power

Of course, other design factors determine the magnitude of the torque and speed.

What Is The Speed Torque Characteristic Of Low Speed High Torque BLDC Motor?

Of course, we know that brushless Dc motor high torque low rpm should operate at:

  • Low speed
  • High torque

So, here are some of the fundamental aspects of speed and torque of these brushless DC motors:

When analyzing the torque of BLDC motors, you should consider:

  • Peak torque
  • Rated torque

Within the rated speed, the torque of the BLDC motor will always remain constant.

However, you should note that you can operate the BLDC motor up to 150% of the maximum speed. But, even as you achieve this, the high torque will begin to drop.

Also, it is important to acknowledge that certain applications that require start and stop require low speed high torque BLDC motor.

Remember, with the load, the motor will require more torque. Of course, it may exceed the rated torque because the motor must overcome the inertial force.

In short, the motor will have peak torque at zero rpm, after which it will reduce as the rpm increase.

Therefore, in the low speed high torque BLDC motor torque analysis, you should consider intermittent and continuous torque zones.

Why Use Low Speed High Torque BLDC Motor?

There are many reasons why you should consider these motors for your applications. They include:

  • They have a better dynamic response – this is due to its small size, high flux density, and weight of the BLDC motor
  • These motors are highly efficient – the BLDC mots have low losses within the rotor. It is because it doesn’t have current carry conductors.

The efficiency varies from 85% to 90%

Also, it has virtually no friction losses, and there are no losses within the rotor windings

  • Guarantee quiet operation due to lack of brushes that can cause sparks and friction
  • You can achieve higher torque depending on the design of the motor
  • It has better speed and torque characteristics
  • Higher torque to weight ratio
  • Guarantees long service lifespan – the absence of brushes reduces unnecessary wear and breakdown
  • Electrical commutations allow for a wide range of speed control
  • It significantly reduced electromagnetic interference

Do Low Speed High Torque Brushless DC Motors Have Limitations?

Yes.

Although these BLDC motors are popular in many applications, they have limitations.

They include:

  • Higher initial cost – Generally, these BLDC motors are expensive. Of course, this is due to the design and use of rare-earth metals in the rotor
  • Complex control systems – controlling these motors requires relatively complex systems. However, the modern semi-conductor systems significantly reduce these control systems’ complexity.

Which Types Of Phases Of BLDC Motor?

Generally, when it comes to choosing BLDC motors, you can choose:

  • One phase brushless DC motor- they are common for torque and low inertia
  • Two-phase brushless DC motors – these motors are not popular
  • Three-phase brushless DC motors –are the most common options. The most low speed high torque BLDC motors are three-phase

How Do You Control Low Speed High Torque BLDC Motor?

Adopting a proper control mechanism will guarantee optimal performance of low sped high torque BLDC motors.

That is, turning stator coils ON/OFF requires electronic components.

There are many variables you can use to control motors speed and torque. They include:

  • Timing
  • Duration
  • Sequencing
  • Amplitude
  • Polarity of pulses

You can use a motor control device or microcontroller unit (MCU) to control the motors effectively.

When it comes to knowing the exact position of the rotor, you can adopt a sensor or sensorless technique.

You will use hall sensors for sensors that you will embed on the stator. They send logic signals which you can use to determine the position of the rotor.

When you opt for the sensor-less technique, you will depend on the back electromotive force.

You can use the voltage to time pulses from the stator.

So, the MCU will generate a drive signal due to the back electromotive force.

Other control options include open-loop control and closed-loop control.

With the open loop, the controller will set a constant speed.

However, if the speed varies with load, you will have to adjust it manually.

Also, there is the closed-loop control mechanism.

Here the controller automatically adjusts, depending on the prevailing conditions.

It uses the error signal to adjust the input signal

Are Low Speed High Torque Brushless DC Motors Bidirectional?

Figure 7 Low speed high torque motor

Yes, you can operate these motors in a clockwise and anticlockwise direction.

You will only reverse the BLDC motor drive pulses.

The best part, you can do this within the BLDC motor controller.

Which Factors Should You Consider When Selecting Low Speed High Torque BLDC Motors?

Before buying low speed high, torque BLDC motors, there are several aspects you should consider. These include:

Peak Torque Of BLDC Motor

Whenever you are calculating torque you need to your low speed high torque BLDC motor, it is important to consider:

  • Load torque
  • The torque due to inertia
  • Torque the motor needs to overcome friction

In addition to all these types of torque, you should consider other factors, such as motor windage loss. Other losses may be due to friction.

As a result, you should include a factor of about 20% to cater to these losses.

Therefore, it implies that the peak torque will be the sum of load torque, the torque you need to overcome friction due to inertia and torque.

You will then multiply the sum of torque by a factor of 1.2.

Root Mean Square Torque

Generally, this is the continuous, low-speed high torque required for the normal operation.

Normally, the root means square torque will depend on the following key aspects:

  • Peak torque
  • Load torque
  • The torque due to force of inertia
  • The torque due to friction
  • Acceleration, deceleration, and runtimes

You can use this equation to calculate the root mean square torque:

 

Figure 8 Torque equation

BLDC Motor Speed

This is the speed your low speed high torque motor will require for normal operation.

It is one aspect that determines the nature of the application. For example, the speed you will use in the conveyor belt is different from that you will use in blowers.

How Does Closed Loop And Open Loop Low Speed High Torque BLDC Motor Compare?

Open look control systems are straightforward.

It controls the voltage you will supply to the low-speed high, torque BLDC motor.

It simply chops the DC voltage. However, the current limiting feature is a popular drawback.

On the other hand, a closed-loop motor control system offers an effective and reliable control mechanism.

This system controls the supply voltage to the motor based on the speed feedback it gets from the motor.

It has a sensor that detects the speed of the motor.

A timer IC or microcontroller uses an error signal to control the motor speed.

Why Is Sinusoidal Commutation Better Than Trapezoidal Commutation In BLDC Motors?

A trapezoidal commutation does not guarantee an accurate and smooth electric motor control mechanism.

This is even critical for motors operating at low rpm, such as low-speed, high-tor BLDC motors.

For this reason, you should use sinusoidal commutation for low speed, high torque brushless DC motors.

Sinusoidal commutation produces smooth motor control.

However, you should note that sinusoidal commutation may result in negative torque at higher speeds.

What Is Back EMF In Low Speed High Torque BLDC Motor?

The winding in the brushless DC motor act as a generator.

That is, they will generate an electromotive force.

According to Lenz’s law, this back electromotive force will oppose the flow of the main voltage.

The magnitude of the back electromotive force depends on a magnetic field, rotor angular velocity, and stator windings number of rotations.

Using back electromotive force has recently played an integral role in controlling sensorless BLDC motors.

At Longbank Motors, we offer a range of electric motors depending on your unique requirements and specifications.

Our motors include a brushed motor, DC electric motor, AC Asynchronous motor, and induction motor.

Contact us today for all your low speed, high torque motors.

Longbank Brushless Motor

Are you seeking the most reliable Brushless Motor producer and distributor? Longbank is an excellent place for you. We are delighted to provide various Brushless Motor models to different nations around the world. Longbank is capable of meeting all of your Brushless Motor needs at a reasonable price.

It is a direct current (DC) electric motor that does not use mechanical brushes or a commutator like a typical brush motor. It offers great features over a brush motor and is more cost-effective in the long term, despite more significant starting expenses. No brushes are rubbing against; therefore, there is no energy loss from friction. Therefore much more energy-efficient than brushed motors and may last up to 50% longer on batteries.

Please tell us about your idea so we can discover the Brushless Motors that are appropriate for you! Longbank provides unique solutions as a prominent Brushless Motor provider. Please email us your product specifications so that we can get started.

Brushless Motor Advantages

  • It doesn’t have any carbon brushes, which means fewer brush replacements and lower maintenance expenses.
  • It offers more outstanding quality and reliability than brushed motors due to electronic control, which allows for finer control of the motor’s speed and position. 
  • It has a lifetime of roughly 6 times that of brushed motors.
  • It has a lower risk of burnout due to sparking difficulties because there is no spark.
  • Because it has a low no-load current, You can use it at low or no load.
  • It is capable of constantly providing maximum torque throughout the rotation.
  • It may include a feedback control system for monitoring and controlling the speed and torque.

You may rely on Longbank as a skilled Brushless Motor manufacturer. BL4835, BL6324, BL7125, BL10045(Low Voltage, OBL5020, OBL6425, and OBL7527 are some of the Brushless Motor models we may supply based on your requirement.

Our firm employs a competent and skilled workforce. We oversee every step of the procedure, from a selection of materials to manufacturing to shipping. Longbank also uses automated manufacturing lines, testing equipment, and cutting-edge technologies to ensure high-quality and consistent Brushless Motor performance.

Our primary goal is to provide you with high-quality Brushless Motors. As a well-certified manufacturer, we will assist you in finding the perfect motors for your business. Whether you have a small or large purchase, we will do our best to meet your needs.

For additional information, don’t hesitate to get in touch with us!

 

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