This new slotless precision torque motor series claims to be the thinnest and lightest yet, challenging its slotted peers in terms of performance. Jake Holmes finds out more…
Known for their high torque density and efficiency, permanent magnet brushless motors come in many different shapes and sizes providing both rotary and linear motion. Slotted motors are used in various applications, from imaging and scanning to metrology and photonics. In all of these applications, smooth and predictable torque while moving is a particular challenge. Enter slotless motors, which are specifically designed to optimise smoothness and create predictable torque output to prevent cogging – cyclical torque with an angle that creates torque ripple and adds a non-linear element to the control of the motor. linear motor
Rather than one trumping the other, application needs often determine if a slotted or slotless motor is more beneficial within a particular scenario. Slotted motors feature a stator with coils wound around its iron teeth, whereas slotless motors do not. Slotted motors, also known as iron core motors, are more useful for applications that require high torque density and high acceleration. However, they can cause cogging by aligning their permanent magnets with the teeth and slots of the stator, resulting in an uneven magnetic effect.
Alternatively, slotless motor designs place only copper phase coils in the air gap of the motor which interact with the permanent magnet flux to create torque. These motors can achieve peak torque with the only limit coming from thermal restrictions. Quicker response times are possible as slotless motors have lower inductance than alternative designs.
Frameless motors manufacturer Alva Industries has released its SlimTorq series of lite and max precision torque motors. Claimed to be the ‘world’s thinnest and lightest’ precision torque motors, the range of slotless thin-section motors are ideal for high-precision applications across land, sea, and air.
The motors are designed with an ultra-thin and compact form factor providing high precision and power. The motor’s brushless design gives higher levels of reliability whilst reducing noise and vibrations, meanwhile its non-skewed windings grant maximum torque output. Quick customisation is possible due to the range of design options factored in.
Nicolas Giraudo, CCO at Alva Industries, says: “We hear all the time from engineers developing systems for high-precision applications that they need to reduce size, weight, and power consumption while improving overall performance.”
A variety of motor sizes are available ranging from 39mm to 130mm outer diameter. The company’s patented FiberPrinting technology is used to manufacture the motors, creating ironless and slotless motor windings. Precision, torque, and adaptability are the focus of this new motor series, with the series having up to 60% copper fill factor.
Jørgen P. Selnes, CEO and co-founder of Alva adds: “One of the key benefits of FiberPrinting is its intrinsic flexible process, allowing us to develop custom windings faster than competitors.”
Alva Industries first demonstrated the new slotless motor at the SPS tradeshow in Nuremberg, Germany, on the 12th of November. Live presentations were available to show how the motor can perform in land, sea, air, and space applications.
The SlimTorq series is suited to a variety of applications including high-precision gimbals, medical devices and surgical robotics, defence and satellite communications, marine propulsion, metrology, and semiconductors.
FiberPrinting is Alva’s process for manufacturing SlimTorque motors, next-generation electric motors and propulsion systems. The technology enables the rapid design and manufacturing of ironless and slotless windings with copper fill factor for any electric motor or generator.
The process allows for the continuous winding of stator mats for ironless and slotless rotary and linear motors. Maximising copper fill allows for customisation of size and stator configuration, while a copper fill factor of 60% ensures minimal electrical resistance.
After producing a FiberPrinted stator mat, Alva’s moulding process converts it into a structural component with tight tolerances. Automation helps to reduce costs whilst increasing quality, as it reduces part-to-part deviations. Application requirements determine the choice of resin, which can vary from thermal performance to water compatibility.
FiberPrinting allows for the manufacturing of stator mats in various shapes and sizes due to its versatility and flexibility. It can change length, width, thickness, and pole size to fit specific requirements. Stator mats can be processed into rotary and linear precision motors.
The poor power and torque performance of traditional ironless and slotless motors have limited their use, due to the low copper fill factor compromising phase resistance and voltage constant.
Using the FiberPrinting process can create a higher copper fill factor, achieving up to 60% and short end-windings. This is enough to boost the performance of slotless motors and challenge slotted motors’ performance levels.
A further limitation of traditional ironless and slotless motors is they can only produce skewed windings. A misaligned magnetic field between the rotor and the one generated by this can result in a lower motor constant. Therefore, FibrePrinting’s ability to produce non-skewed motor windings with an aligned magnetic field to the rotor improves the performance of both power and torque density.
There are different ways of assessing which motor is best for various products. Basing your decision on what the end use of the device is may be the best route. Different metrics measure how effective motors are.
With a higher motor constant, motors can deliver greater torque while maintaining a lower surface temperature and consuming less power, making them more efficient. Motor constant metrics are also a useful way of benchmarking motors, as this makes comparison easier and allows manufacturers to assess what motor fits their needs best.
The advancement of slotless motors allows for smoother operations across a range of industries. While a slotless motor will not be the correct solution for all applications, it can significantly enhance the applications it is suited to.
Designing more efficient slotless motors allows for smoother operations. Slotless motors with a brushless design can provide a more seamless operation without any risk of cogging occurring.
To receive our free weekly NewsBrief please enter your email address below:
large brushless motors © Setform Limited 2019-2025 | Privacy policy | Archive