Why do DC Motors Perform Well in the Industrial World?

DC motors are still useful in industry. These motors remain among the finest options for a broad range of applications. DC motor designs, such as permanent magnets, compound wound, shunt, and brushless are just some of the kinds of used today. The main concept behind these designs is quite the same.

In basic terms, this involves placing a current carrier conductor in a magnetic field. Once these conductors receive power, the motor starts rotating. Generating electromagnetic fields may either be in the stator or the rotor. These basic designs are how DC motor designs differ from each other.

DC Motors Advantages

For the most part, DC works better in some applications than AC motors. DC motors are cheaper options compared with Inverter-duty AC drives and motors. There’s also a large base of professionals specializing in the operation of DC motors. These motors have been used in several applications for over a century. For instance, industries relying on DC for a long time opt to replace an old one with a new version. This exchange is a more efficient and less expensive way to do it instead of choosing an AC motor and drive. Switching to an AC motor application involves redesigning and reinventing the motor circuit to make way for a motor replacement.

Another advantage that DC motors offer is the ease of maintenance and troubleshooting. When problems occur, there’s no need to deal with field excitation when servicing DC motors. With the simplicity of the motor’s design, an ordinary industrial electrician should be able to complete the brush replacement process.

Speed Control

Controlling the motor speed is also not an issue with DC motors. All it requires is the use of a local potentiometer to make any change to the terminal voltage. Thus, the control, servicing, and maintenance of DC motors go by as quick and cost-effective as possible.

DC motors are dependable when it comes to variable speed control. In fact, before developing VFDs in the early 1980s, DC motors were the standard option for controlling motor speed. The same holds true with developing full torque at a lower speed, another capability of DC motors. This type of motor ensures a full operating range of machines from zero to their base speed without compromising their condition.

DC Motor Torque

Mixers, conveyor belts, extruders, and elevators need constant torque loads. With the DC motor’s full torque at zero speed, it is efficient for these applications to resume their function and not oversize as they do so. Since DC motors do not involve any field coil in their stator, the motor size is not as big as that of AC motor. This smaller size is the reason why space-constrained applications take advantage of this unique feature that DC motors have.

Modern AC motors have been catching up with DC when looking at performance and function. Despite new trends, DC motors are still more efficient when used for general purposes. In fact, You need a higher end and more expensive type of AC inverter duty motor just to achieve the same low-speed performance from a DC.

A DC inverter drive is much simpler than an AC inverter drive. For instance, it is necessary to make adjustments to the incoming power in AC drives just to produce DC. The DC inverter converts the current back to AC while powering the motor. Making it simpler, DC motors use different energy sources, such as batteries.

There are variations with the output power quality based on the type of DC drive used. The ripple current produced by the DC drive allows us to measure the output power. When there is a high ripple current, the motor overheats. This overheating creates premature brush damage and failure. If your application requires a continuous power application, make a goal of a 1.40 or less form factor. An excellent option for current source is a battery with a 1.0 form factor. The battery powers a DC motor by providing a constant current and voltage without resulting to overheating issues or early signs of wear.

Final Word

Various applications requiring a constant low speed or adjustable speed torque rely on DC motors. Compared to AC motors, DC motors provide the best performance and longer lifespan when used in reversing or dynamic braking.

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Originally published at www.lselectric.com on April 6, 2017.