Zero cogging BLDC motors
We offer two types of cogging-free motors from our manufacturer partner ThinGap.
TG-Series: Ironless for high power density.
LSI-Series: Slotless design with back-iron for high torque density
The stator of the TG motors has no iron core ("ironless"). The motor is designed to run at high speeds to provide high power density. Thus, the ironless stator is desirable, as it reduces the back EMF. The back EMF is a voltage generated by any permanent magnet motor which is spinning. The amount of back EMF generated by a permanent magnet motor depends on a parameter called the "back EMF constant". The TG motors are designed to have a low back EMF constant.
The LSI motors have a slotless iron lamination stack which acts as a return path for the stator's magnetic field. The stator winding is bonded to the inside of the iron lamination stack. The lamination stack also provides a good heatsink for the motor at low speeds which makes it very useful for applications like gimbals or optics.
Please keep reading to find out more about each family, or, contact us to discuss your requirements with an experienced MACCON engineer.
LSI series of cogging-free slotless motors
ThinGap’s LS line targets low speed, high precision applications such as gimbals, optics, and precision robotics.
Highest torque density with high power capability. Low thermal resistance at any speed.
Key features:
- Smooth motion with zero cogging and ultra low torque ripple when paired with a sinusoidal drive
- High peak torque to continuous torque ratio
- Optimized for ultimate torque density
- Stationary lamination stack for typical bore mounting
- 3 phase brushless, sinusoidal waveforms < 1% THD
- Non-saturating facilitates very high peak torque (typically >4:1)
- Exceptionally large clear apertures
- Frame-less kit facilitates deep integration
- Large through hole
We understand that your application has special requirement, so we offer custom motors, or modifications to our standard motors, to meet your specific design requirements to make sure you get the perfect motor for your application. Please contact us to discuss your requirements.
TG series of ironless cogging-free motors
Our manufacturer partner ThinGap’s three-phase, permanent magnet, Brushless DC (BLDC) ring motors are made with proprietary ironless stator technology. The result are motors and generators that are lightweight and high torque which deliver high-power at exceptional rotational smoothness. The “ring” architecture allows for more highly integrated, more compact and lighter system designs.
Unlike slotless motors, only ThinGap delivers “True-Zero™” zero cogging torque. That’s because ThinGap’s completely ironless stator has no magnetic interaction with the rotor until purposely energized by the controller. This gives them exceptionally precise rotation and unmatched rotational smoothness.
ThinGap Motors offer these advantages:
- High torque-to-weight ratio
- Lightweight and low inertia
- Improved system integration due to our ring architecture
- “True-Zero ™” Zero cogging torque for precision positioning and smooth rotational velocity
- High power density scalable from 50W to 550kW
- Diameters from 40mm to 900 mm
We understand that your application has special requirement, so we offer custom motors, or modifications to our standard motors, to meet your specific design requirements to make sure you get the perfect motor for your application. Please contact us to discuss your requirements.
Servo control of cogging-free motors
When control engineers contemplate difficult tasks such as micrometre / nanometre positioning, as well as aiming for speed stability at very low speeds, they usually think about several key success factors.
Firstly, eliminating cogging force or cogging torque. This is easily achieved by using cogging-free motors such as the ones shown on this page. In addition, it is well known that a high-resolution encoder system is required. This could be an optical encoder system, such as the ones shown at this link. Finally, they consider the type of servodrive which should be used. Most servodrives use pulse-width modulation of the supply voltage to achieve the required current in the motor windings. However, this leads to current ripple, which in turn produces torque ripple. The torque ripple makes it impossible to achieve high-precision servo tasks. The solution is to use a non-switching servodrive, also known as a linear amplifier. The MACCON Family of non-switching servodrives can be found at this link.
With the following success factors in place:
- Ironless motor
- High-resolution optical encoder
- Non-switching servodrive (linear amplifier)
we can now look at the remaining puzzle pieces. Of course, we should never forget the issue of cables. High-quality motor and feedback cables which are properly shielded against electromagnetic interference are a must. Last but not least, we need an experienced commissioning engineer to get the described system working. MACCON has a core team of experienced engineers who have supported machine-builders in semiconductors and optics / photonics to achieve the most difficult of nanometre positioning and low-speed motion tasks. Contact us to discuss your needs, engineer-to-engineer!
