AC vs. DC Motor: What’s the Difference Between Them?

Are you looking for a new motor for an application or piece of construction equipment? Before making any purchases, you must know whether you need to buy an AC motor or a DC motor.

Both types of motors have practical uses in many industries. However, they differ in cost, efficiency, reliability, and performance. By assessing your project requirements, you will know the best motor for you using this guide.

Keep reading to learn about the differences between an AC and a DC motor. 

AC Motor

AC means alternating current. An AC motor uses AC power which reverses the current direction, alternating between positive and negative. 

There are two major types of AC motors — synchronous and induction. 

The synchronous motor rotates at the same rate as the frequency of the supply current. 

The induction motor is the most common type of AC motor. The output rotation is proportional to the applied frequency of the alternate current. Electromagnetic induction creates the electric current that turns the rotor. 

AC motors are robust, durable, and affordable. In addition, they have a longer lifespan and lower repair costs than DC motors.

AC motors are used in large-scale, continuous-speed applications where the motor speed is slow to medium. This is because they are resistant and slow to respond to changes in speed when the load changes. 

AC motors are best for applications that need high speed and variable torque. They tend to lose torque at higher speeds.

DC Motor

On the other hand, a DC motor uses DC power. DC means direct current. The power flows in one direction, like in a battery. As a result, DC motors are usually more efficient than AC motors.

Additionally, they are also more expensive and have high repair costs.

There are also two major types of DC motors — brushed and brushless. 

Brushed motors use a carbon brush to conduct electricity through an internal commutator.

Brushless motors are similar to brushed motors, minus the brushes. Additionally, they have a specialized circuit to control power speed and direction. Furthermore, the motor uses magnets mounted around the rotor to improve efficiency. 

Brushed motors have a shorter life span than brushless motors because of the wear and tear of the brush. But, they have a more straightforward design, so they aren’t as expensive as a brushless motor.

DC motors are quick to respond to a change in the power load. Therefore, they are best for applications that need high torque and variable speed. 

Domestic applications and robotics most often use DC motors because they need fine speed control. 

Get Your Motor Today

With this guide, you can decide if you need an AC motor or a DC motor for your application. If you still aren’t sure, you can also ask a professional for help.

Contact us at KOR-PAK corporation today for more information on the different motors, and receive a free quote! Our experts are here to help you at any time.

Your Ultimate Motor Coupling Purchasing Guide

While there’s no set standard for how long any piece of equipment lasts, one of the best ways to ensure you get the most life out of anything is maintenance.

When you replace broken or worn components of your motor, like your motor coupling, you’ll find that your whole system lasts longer. If you’re willing to put in the work for replacing these components, your whole system will reward you with efficiency.

Here is what you need to know when you’re looking to buy a new coupling for your motor.

Figure Out The Size

When you’re looking to replace a motor coupling, especially one that worked well for some years, you need to make sure you order the right replacement. When looking to get the OEM part or the closest one to it, you need to figure out how to identify it to reorder it. This will help you maintain the life of your motor.

You’ll need to find out the horsepower of the motor and the RPM at the point of the coupling to identify the size. There is a specific shaft, and keyway size you need to make sure matches the old one.

Then check the shaft separation, also known as BSE, which is the distance between your two shaft ends. If you also know the type of driven equipment that you’re using it with, you’re all set.

How Are You Using It

Along with the size, you need to figure out the application factors which help you decide on a coupling. Not all couplings are created equally, even ones that are made to fit a specific type of motor.

You’ll need to know the operating temperature that you’re putting it under and any chemical exposure that you can expect. There are run cycle types, whether continuous or start-stop motors that make a difference. You’ll even need to account for space available for your couplings.

Figure out the misalignment handling requirements, and you’ll know which to get. There are angular, parallel, and axial misalignment possibilities and your coupling will be different depending on which one you have to account for.

Beware of Misalignment

When you’re looking at the rating for the coupling that you’re replacing, there is a number that relates to misalignment. Each coupling type will tell you how much is the maximum allowable misalignment you can have. If your coupling is set to be aligned at the maximum permissible misalignment, you need another coupling.

If you go beyond the allowance, then you’re going to see a severe drop in the life of your coupling. While you can’t precisely calculate the life of a coupling, the factor of misalignment is going to make a massive difference.

A New Motor Coupling Will Get You Back on Track

When your system has been giving you trouble, a motor coupling could be the only thing standing in the way of reaching peak efficiency. So long as you find the component that fits your system, you’ll be able to have a motor that works as if it were brand new.

If you need help in servicing and maintaining all of your equipment, check out our latest guide.

What’s Right for Your Load? AC Motor vs. DC Motor

Given that 70% of the time that we put into work gets wasted, a lot of that time is wasted because of the wrong tools. If you’re deciding on an AC motor vs. a DC motor, then you need to understand their applications better. One is better for one type of project while the other might be what you need for a project you haven’t considered using it for.

Here is everything you need to know about how motors impact your load.

Understanding Load Needs

When you’re operating equipment with a motor, it doesn’t always have a load attached. Sometimes the motor itself is doing all the work while the equipment is moved around by an operator.

When a motor is bearing a load or dragging an object around, it’s dealing with external resistance that takes mechanical energy. If you calculate how much real power your equipment has, the raw mechanical energy is going to be dragged down by your load. Some internal factors change how a motor works, but much of the change comes from external factors.

When a shaft rotates freely, then the only resistance you have to worry about is from internal factors.

When To Use AC motors

Alternating current motors don’t have a lot of the control that direct current motors have. However, with a frequency converter, an AC motor and DC motor vary, far less.

If you’re working on a project that doesn’t require a lot of stable motion in your motor, then you should use an AC motor. If fixed speed isn’t an absolute must, then an AC motor is fine. The only thing is that if you need to use your motor at a deficient speed, AC needs a certain frequency just to get started and could fluctuate as well.

For the best deal when it comes to performance and torque output, however, AC motors give you the best of both worlds. You’ll have a powerful and strong performance that doesn’t struggle with the resistance of loads. You could end up remaining at a steady pace in spite of a load.

When To Use DC Motors

Direct current motors are good for a lot of applications that AC motors aren’t prepared for. When you need more torque while starting your motor, you can get that high starting power with DC. They overcome the initial inertia that a load puts on a motor when it’s just getting started.

While you might require some versatility, AC won’t always cut it. You can modify DC motors much easier in both high power and low power applications.

When you need to deal with a project where your load is your priority, not precision, DC motors come in handy.

The AC Motor Vs. DC Motor Debate is Easy

When it comes to deciding between an AC motor vs. a DC motor, it all comes down to your load. Whatever is better for your load, that’s the motor to choose.

To keep your motors in good shape, follow our guide for equipment maintenance.

DC vs. AC Motor: What’s the Difference?

You need an industrial motor, but what kind should you get: AC or DC?

That depends on what you’re trying to accomplish with the motor. There’s no clear winner in the DC vs. AC motor debate, but learning more about how each motor works can help you decide.

First, let’s answer the question, “What is the difference between AC and DC motors?”

How AC Motors are Built

An AC motor uses alternating current. That’s where the “AC” part enters the picture.

There are two types of AC motors. The first is an induction motor, also known as an asynchronous motor. It works like this: A part called the stator winds and produces electromagnetic induction, which is then turned into the electric current that propels the rotor.

Then there’s the synchronous motor. If you’ve noticed that synchronous sounds like “synchronized,” then you’re onto something. The shaft rotates in sync with the supply current’s frequency.

The Edison Tech Center in Schenectady, New York, calls induction motors “the most popular electric motor in the world.” It credits the motor’s longevity to its simplicity of design.

Synchronous motors aren’t as simple, but they’re still popular.

How DC Motors are Built

In DC motors, the “DC” stands for “direct current.” That’s what these motors use for power; it has nothing to do with the District of Columbia.

Their power often comes via batteries. If you took a close look at a DC motor, the parts you’d find would include a rotor and an axle. They come in brushed and brushless models.

Both models also use magnets, but the magnets work in different ways. The brushless models are newer, and they’re generally considered more efficient than the brushed models, due in large part to how the magnets are placed.

Now that we’ve covered the difference between AC and DC motors let’s look at the different applications for them.

DC vs. AC Motors: How We Use Them

Did you have a piece of toast for breakfast this morning? Maybe a bagel instead? In either case, you used an AC motor to warm up the bread before you ate it.

When you take the toaster cord and plug it into an electrical outlet, you probably aren’t thinking, “I’m connecting to the AC power supply,” but that’s what’s happening.

Maybe you prefer to stick with coffee from the drive-thru in the mornings. If so, guess what? The friendly barista brewed your espresso with an AC motor.

If you had an electric car 20 years ago, it would have been powered by a DC brushless drive. In the induction motor vs. DC motor debate, the latter is winning handily. Only a few electric vehicles have used an induction drive, including the Tesla Roadster.

If you’ve gone off-roading in an ATV, though, you can thank a DC motor. They’re also used for things like electric wheelchairs, chemical pumps, and sprayers.

Some types of motors come in both AC and DC versions. For instance, if you wanted to, you could switch between an AC and DC crane motor.

More About Motors

Want to know more? There’s no need to wring your hands as you ponder a DC vs. AC motor.

If you’ve got additional questions, we can answer them. We provide all sorts of motors for all kinds of industrial uses, so contact us today.

Switching From a DC to AC Crane Motor? What You Need to Know

Trying to decide if you should switch from DC to AC?

Before you make the decision, you have to know the difference between DC and AC motors and what kind of benefits they give you.

Take a look at this guide to find out if you should make the switch.

DC vs. AC Motors: What’s the Difference?

The main difference between these motors is the current they use.

For example, DC motors are power because they take direct current electrical energy and change it into mechanical energy. AC motors do the same thing; only they use an alternating current to draw their energy.

But what does this mean?

Well, let’s break it down.

DC Motors: These motors change the current’s direction by using a commutation ring, a system of carbon brushes, and a rotating armature. The motor has several magnets inside of it that make the motor turn by interacting with a rotor.

AC Motors: There are two different types of AC motors; one is an induction motor, and the other is a synchronous motor.

The induction motor gets power from the input voltage by using a serious of coils. This makes a stator field, and that powers the rotor field.

The synchronous motor creates a magnetic field by using either slip rings or magnets, which is called a precision supply frequency.

From DC to AC: Is the Switch Worth It?

Some benefits come with making the switch from DC motors to AC motors. So, in short, getting AC upgrades is worth it.

We’ll take a look at some of those benefits and find out how they can save you a lot of money and hassle in the future.

But first, let’s look at some of the downsides that come with DC motors.

The Downsides of Using a DC Motor

DC motors may be effective, but they are also older than AC motors. With age comes complications.

As more and more people switch from DC to AC, DC technology is getting harder to come by. Some types of DC technology aren’t available anymore at all, so making repairs to your DC motor can be time-consuming and difficult.

Even if you find a place that can make the DC technology you need, it can take several months to build. In the worst cases, you can wait for nearly half a year for the right parts.

If your company depends on a DC motor, a seemingly simple repair can stop your progress for a long time.

The Benefits of Using AC Motors

AC motors are newer, have lower HP, and use significantly less amperage than DC motors. This means they use a fraction of the power DC motors use. In most cases, making AC upgrades will cut your energy consumption and attendant costs nearly in half.

AC motors have more available technology at much lower prices, and they can include new safety features.

Because of this, you’ll probably find AC motors last longer than DC motors as well.

What to Know When You’re Making the Switch

The biggest drawback of switching to AC motors is a lack of AC power supply. But if your facility is to run on AC power it will save you money in the long run.

Ready to upgrade your cranes? Take a look at some of our services.

Top 5 Advantages Of Our Servo Motors And Drives

People realize that the common hydraulic motors today aren’t cutting it anymore. They can be expensive, cause oil problems, and occasionally leak.

But luckily there’s a better option out there.

Electric servo motors and drives have been evolving for some time now. And they seem to be great for all different industries. That’s why we’ve gathered the top 5 advantages of servo systems to show you exactly how great they really are.

Speed of Servo Motors and Drives

Many people debate the speed and acceleration of servo motors and drives compared to those of hydraulics. The truth of the matter is that hydraulics aren’t the fastest because of its compressions of oil and flexibility of its hoses and lines that expand.

If hydraulic systems were designed better, then the speed may be better and closer to that of a servo system. But for the time being servo motors and drives are more impressive in the category.


The next advantage of these systems is the versatility servo technology. They can be used for so much, and there are different kinds as well.


Servo motors are in a wide range of machines.

Inside of a servo system is a motor that toys also often come with. This motor is called a small direct current motor, and it runs on electricity from a battery.

They are also in cameras. Specifically, in it’s Auto Focus to help the camera’s lens sharpen images. Automatic door openers also use the motor to help signal it to open.

Another use of this system is the robotic arm that helps move along assembly lines. The servo motor helps make the joints of the robotic arms move.


The servo motors in the servo system come in many different forms.

  • Positional- this is the most common and can rotate in certain directions.
  • Continuous- this one is similar to positional but can rotate in all directions.
  • Linear- this one has the features of the previous ones but has additional gears.

Something that varies in the different types is how they are used as well and their availability. The positional servo motor can be found in smaller applications, while the continuous and linear motors are geared towards larger projects.

Exerts Less Heat

Hydraulic machines let out a large amount of heat. This is mainly through its work with oil and overall design of the machine.

Servo motors and drives release such a small amount of heat. So small in fact, that operators usually need to employ another system that keeps the oil at temperature.

Service of Pumps

Another large difference between hydraulic machines and servo motors and drives is maintenance.

While hydraulic machines are generally cheaper to buy the servo systems will give you your money’s worth in how much it saves, as well as cut down costs on maintenance.

Hydraulic machines will need to be serviced often as their pumps will need to be changed. And their pumps are also more expensive than those of a servo system.


Servo motors and drives are also extremely simple machines. This makes work and maintenance a lot easier to carry out.

An all-electric motor will have fewer parts than those that are hydraulic-based. As a result, an electrician will be able to work on it without needing hydraulic knowledge.

These servo systems also use technology that will make repairs easier. They use feedback devices that help catch errors and correct them to help better performance.

More Motor Tips

It’s important to choose the best parts for any project that you’re doing. Especially when it comes to motors as they can be a big part of the system you’re working with.

For more information on motors, check out this blog post.

AC and DC Motors: What You Need to Know

Do you know the difference between AC and DC motors?

If you’re shopping for motors, it’s helpful to know how each one works so you can decide what’s best to meet your needs. That’s why we’ve put together this essential guide to help you learn the difference between AC and DC.

Read on to find out what you need to know!

AC and DC Motors: A Short Guide

Most motors are either direct-current (DC) or alternating-current (AC). Let’s take a look at the basic difference between the two types of motors.

The essential difference between the two motors is right there in the name. AC motors use an alternating current to change electrical energy into mechanical energy. DC motors use direct current to achieve the same goal.

However, there are more detailed differences in the way each type of machine operates depending on its power source. Let’s take a closer look at what those are.

DC Motors: The Details

DC motors usually use a system of carbon brushes plus a commutation ring to change the current’s direction using a rotating armature. Fixed magnets inside the motor interact with an internal rotor to get the motor to turn.

Because of the carbon brushes, DC motors tend to have more limited lifespans. Most can last for about 1,000 to 1,500 hours, but if under a heavy load they may last for as little as 100 hours or less.

In ideal conditions, DC motors can operate much longer, though. These motors are very efficient, and lose efficiency only in a few specific areas. The winding and friction of the brushes are two places where these motors lose efficiency.

AC Motors: The Details

The AC induction motor, a common type of AC motor, uses a system of coils that get their power from the AC input voltage. This input voltage creates a stator field, which in turn induces the rotor field.

Another kind of AC motor, the synchronous motor, works using precision supply frequency. This kind of motor uses a current from either permanent magnets or slip rings to create a magnetic field.

AC synchronous motors are faster than AC induction motors because the induction motor’s speed is slowed down by the lack of synchronization.

AC motors are designed to operate according to a performance curve that aligns with the motor’s greatest efficiency. If the motor operates at a different point on the performance curve, efficiency will be lost.

Because AC motors need to use extra energy to create a magnetic field, they operate less efficiently than DC motors.

AC and DC Motors: What’s Best for You?

Both of these motor types operate differently and have a different performance. Depending on the task at hand, one kind of motor may be right for the job.

When you need to have external control of the motor speed, DC motors are usually best. However, AC motors are ideal when you want a strong performance for a longer period.

You should also consider wear and tear, and the cost of replacement parts. An electric DC motor will usually have more moving parts that are more costly to replace. For cheaper repairs, you’ll want an AC electric motor.

Need to buy the perfect motor for the job? We’ve got what you need! Check out our selection here.

The Difference Between DC and AC Motors

Looking for a new motor?

It’s important to know the difference between DC and AC motors before you make your purchase.

While DC and AC motors perform the same function, there are some critical distinctions to keep in mind.

Read on to learn more.

Power source

AC motors rely on an alternating current (A.C.) for their power. This involves an electric current that changes back and forth over time.

On the other hand, DC motors use a direct current power source (D.C.) in order to operate. Direct current power sources include batteries, solar cells, and DC power converters.

AC motors require external assistance in beginning their operation. DC motors can start on their own.


There are two different types of AC motors: Induction and synchronous motors.

Induction AC motors rely on an induced current while synchronous AC motors rotate at supply frequency.

AC motors can be single or three phase.

There are also two types of DC motors: a DC motor with brushes, and one without brushes.

All DC motors are single phase.

Construction and Maintenance

An AC motor incorporates a stator and rotor and several other components.

Because AC motors do not require brushes, they don’t necessitate a lot of maintenance.

DC motors are commutated mechanically. This means that they require more maintenance than AC motors.

Life Expectancy and Cost

AC motors are, in general, built to last. They are tough, industrial motors that can withstand rugged conditions.

These motors are also designed to provide power over longer stretches of time.

DC motors require more maintenance and generally have shorter life spans than their AC counterpart.

DC motor parts can be expensive to replace once damaged or worn down.

As a result, DC motors tend to not be as cost-effective as an AC. AC motors are generally inexpensive and outlast DC motors in performance and durability.

Speed Control

DC motors have the advantage of external speed control. This is especially useful in situations where the motor speed needs to be monitored externally.

An AC motor’s speed is controlled by changing its frequency.

Application and Use

DC motors are still really useful for a variety of industrial purposes. This includes paper and steel mill machines.

AC motors are ideal for any industrial application that requires high and extended power performance.

An AC motor can operate in multiple situations and does not depend upon the quality of the power current or its flow.

These motors are used for more general purposes than DC motors. They are starting to take over the motor market as a more durable and long-lasting motor.

The Takeaway on the Difference Between DC and AC Motors

The basic difference between AC and DC motors is in their source of power. These motors are also built differently and have very distinct life expectancy.

If you are deciding between a DC or AC motor, it’s important to keep in mind what you intend to use your motor for, and what type of performance you are seeking.

AC motors tend to be more durable and cost-effective, in comparison to DC motors.

Still undecided? We can help you find one that suits your industrial needs.

Why You Should Trust SEW for Servo Technology

What Is Servo Technology?

Servo technology, otherwise known as a servomechanism, uses error-sensing technology to make automatic corrections to the output of a machine or device.

This eliminates the need for constant user input, as the device makes adjustments itself.

It sounds complicated, but it isn’t. In fact, you probably use some kind of servo technology every day. It’s all around us.

Examples of servo technology include cruise control on a car, conveyor belts in production lines, autofocus on a camera and automatic doors.

Why Use SEW for Your Servo Technology?

Industry Experience

SEW has been around for more than 80 years.

During that time, SEW- Eurodrive has built a history of leading innovation in the industry of servo technology.

They created the first variable speed gear motor and the first motor with energy-efficient copper rotors.

You can be certain that they’ll be on the frontline of all future developments in servo technology.

Exceptional Customer Support

With some companies, once you’ve bought a product, you’re on your own from there.

That’s not the case with SEW-Eurodrive.

Using SEW means being you’ll receive customer care and guidance long after you’ve made your purchase.

SEW offer 24-hour technical support in case of emergency. Their support staff includes not only customer service staff, but engineers, technicians, and product specialist.

Whatever your issue, you can be sure that they have the right people on hand to help you.

Award-Winning Production

SEW has been recognized for excellence in innovation, environmental ability, and employee empowerment.

In 2003, they won the European Motor Drive Vendor of the Year Award.

Their manufacturing facility was also honored with Plant Engineering Magazine’s Top Plant Award in 2007.

An Extensive Product Range

SEW boasts the broadest product range there is in the world of servo technology.

Their range includes gearboxes, frequency inverters, AC and DC motors, automation systems, applications, and software.

SEW’s products are made in such a way that they can be combined and configured in any way the customer requires.

This means that no matter what your needs are, SEW can customize a system that suits you.

Fast Delivery

SEW offers rapid delivery throughout the US.

They are able to do this because their products are not distributed from one centralized place.

They have a number of regional assembly centers, each one of which stocks a huge and varying range of products and spare parts.

This means that you don’t have to wait around for delivery or repairs.

How to Buy SEW Eurodrive Products

Servo technology undoubtedly makes our lives easier. It’s intelligent, versatile, fast, and cost-effective.

SEW-Eurodrive is the leading producer of such technology, and with their wealth of expertise and proven excellence in the industry, there’s no reason to go anywhere else.

These are just some of the numerous reasons why you should invest in SEW Eurodrive products.

If you’re looking to get hold of some for yourself, we can help.

Contact us for a quote on SEW products.

The Benefits of Using a Sumitomo Inline Drive

You already spend a ton of time performing routine maintenance on your company’s assets, right? Sometimes we can get distracted by servicing the big things. But smaller parts such as our inline drive mechanisms can fall by the wayside.

Don’t let this happen!

Whether you need to add a drive to your machinery or perform a replacement, get in line now and read on about why this piece is essential to your success.

Say Hello to Sumitomo

Of the several parts that go into your industrial machinery, the humble drive may not stick out as something you’ll come to rely on time and again, at first.

However, if you opt for the Sumitomo option, you will definitely start to rethink that.

Named by the Austrian Mining website as “unsurpassed by any other inline drive on the market,” and called “world-beating,” these drives offer benefits including:

  • 500 percent shock load capacity
  • Ratios that vary between 1 and 3 stages from 6:1 to 1,000,000:1
  • Low noise and inertia
  • High energy efficiency and heat dissipation

Take a poll of your workers and find out what they think of your current drives and what they’d like to see different.

For example, unlike most drives, the Sumitomo Cycle 6000 series has two-thirds of its reduction components keeping in contact at all times.

This varies from the traditional drive that has gear teeth with limited contact points.

These drives stand up to give you and your team long-life and performance even under extreme applications and conditions.

Where You’ll Use It

Thinking your industry just can’t find a place for this type of drive?

Think again!

We’ve seen the Sumitomo inline drive find an incredibly valued home at places like wastewater treatment facilities, automotive plants, construction zones, paper and pulp developers, poultry processors, and sawmills.

You can’t take a chance to not try this part out in your business!

Get Your Inline Drive Online

There’s something to be said about heading to the parts shop and walking out with your prize in hand. But as industrial manufacturing focuses more customization, it can be difficult to find what you need in the store.

Don’t waste any more time at those brick and mortar shops.

Instead, you can visit Sumitomo online and shop from thousands of parts, models, and features to fit your exact industrial manufacturing needs.

By the way, when you’re shopping around online, you can also check out Sumitomo message boards, reviews, and videos of the drive in action.

There are also options to chat with fellow enthusiasts and see what else is coming down the line for the future.

Sumitomo Got You Stumped?

Been chasing a particular part?

Driving all over for a missing inline drive?

You’ve come to the right place. We are experts in these drives and love to chat with our customers about them.

Click here and send us a message about your particular drive. You can even upload an image directly from your existing machinery!

We’ll get back to you very quickly and help get you on your way.