Motor Technology Comparison

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Efficiency - Peak

TURNTIDE SMART MOTOR

EXCELLENT

Turntide has very high peak efficiency at rated speed and rated torque.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

AVERAGE

Premium efficiency IMs have average efficiency at rated speed and rate torque.

STANDARD INDUCTION MOTOR (IM) W/ VFD

AVERAGE

Premium efficiency IMs have average efficiency at rated speed and rate torque.

PERMANENT MAGNET MOTOR

EXCELLENT

Rare earth permanent magnet motors have very high peak efficiency at rated speed and rated torque.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

GOOD

SynRM have good peak efficiency at rated speed and rated torque.

Efficiency - Across Full Speed/Torque Range

TURNTIDE SMART MOTOR

EXCELLENT

Turntide has high efficiency over a wide operating speed range. This is especially important in variable flow applications where, unlike the fixed speed induction motor, throttling of the flow can be avoided.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

POOR

The efficiency of IMs drops drastically when operated away from rated conditions.

STANDARD INDUCTION MOTOR (IM) W/ VFD

AVERAGE

The VFD allows the speed of the IM to be varied, but the efficiency drops significantly when operated away from rated conditions.

PERMANENT MAGNET MOTOR

EXCELLENT

Rare earth permanent magnet motors typically have high efficiency over a wide operating speed range.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

GOOD

SynRM have good efficiency over a wide operating speed range.

Power Density [kW/kg]

TURNTIDE SMART MOTOR

Very Good

Owing to the higher efficiency and a rotor that is free of bars and permanent magnets, the Turntide Smart Motor System is capable of absorbing higher current and therefore has very good power density.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Average

Because of the bars in the rotor and longer end turns on stator, cooling can be a challenge, which leads to lower power density.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Average

Because of the bars in the rotor and longer end turns on stator, cooling can be a challenge, which leads to lower power density.

PERMANENT MAGNET MOTOR

Excellent

The permanent magnets reduce or eliminate the need for the magnetizing current required by IMs which leads to excellent power density.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Good

Owing to comparatively lower efficiency, the power density is limited by heat dissipation capabilities. Additionally, the “rotor web” wastes more active material and is susceptible to local magnetic hotspots.

Torque Density/Capability

TURNTIDE SMART MOTOR

Excellent

Due to the very high copper fill in the stator, high current densities are achieved leading to excellent torque density.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Poor

The IM has very limited torque capability and cannot be operated significantly beyond rated torque conditions due to the increased losses at high slip conditions.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Average

With the VFD, slip can be managed but the system is still limited to operation well below the motor speed/torque breakdown point which is well below the Turntide motor for the same frame size motor.

PERMANENT MAGNET MOTOR

Excellent

Due to the rare earth permanent magnet field flux, the stator current is used directly for torque production leading to excellent torque densities and capability.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Good

Low saliency ratio, magnetic saturation, and lower efficiency limit the torque production capabilities beyond the rated torque and thus resulting into lower torque densities.

Reliability & Fault Tolerance

TURNTIDE SMART MOTOR

Excellent

Simple construction and stator/rotor structure make the Turntide motor more robust. Also, each phase is individually controlled so electrical faults can be readily identified, isolated, and compensated to resume operation.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Good

Distributed windings decrease reliability/life due to proximity of interphase windings and winding forming during the manufacturing process.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Good

Distributed windings decrease reliability/life due to proximity of interphase windings and winding forming during the manufacturing process.

PERMANENT MAGNET MOTOR

Average

Distributed windings decrease reliability/life due to proximity of interphase windings and winding forming during the manufacturing process. Additionally, permanent magnet motors have demagnetization vulnerability at elevated currents/temperatures as well as magnet retention issues.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Good

Distributed windings decrease reliability/life due to proximity of interphase windings and winding forming during the manufacturing process.

In-Rush Current/Start-up Torque

TURNTIDE SMART MOTOR

Excellent

Turntide does not have a large inrush current problem because the motor controller regulates current. It has high starting and overloading torque capability.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Poor

The in-rush current of an IM is typically 5 to 7 times the continuous value. The IM has significantly lower starting torque capabilities than the Turntide motor.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Average

The in-rush is limited by the VFD. The IM with VFD has better starting torque than a line feed IM, but still significantly lower starting torque capability than Turntide.

PERMANENT MAGNET MOTOR

Excellent

The in-rush is limited by the drive. Operated within the current/temperature limitations of the rare earth permanent magnets, these motors have excellent start-up torque.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Good

The in-rush is limited by the drive. Start-up is on par with IMs.

Ease of Manufacturing

TURNTIDE SMART MOTOR

Excellent

The windings in the stator are concentrically wound around the stator pole with short end turns. These are inherently easier to wind and insert. The rotor is a laminated stack of steel with no slip rings, brushes, bars, magnets, or other secondary manufacturing steps than just stamping.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Average

The IM uses distributed windings in the stator, which require additional tooling and assembly time. The rotor laminations have copper or aluminum bars inserted or cast into the rotor laminations. This is considerably more complex.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Average

The IM uses distributed windings in the stator, which require additional tooling and assembly time. The rotor laminations have copper or aluminum bars inserted or cast into the rotor laminations. This is considerably more complex.

PERMANENT MAGNET MOTOR

Poor

These motors typically use distributed windings in the stator, which require additional tooling and assembly time. The rotor typically has high energy product magnets which necessitates special tooling for assembly.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Average

The SynRM motors typically use distributed windings in the stator, which require additional tooling and assembly time. Also, SynRM motors have complex rotor laminations for flux manipulation, which adds special requirements on rotor lamination stamping & stacking.

Speed, Range, & Operating Capability

TURNTIDE SMART MOTOR

Excellent

The Turntide motor is designed to operate across a very wide speed and torque range and still maintain high efficiency.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Poor

The IM is only designed to run at a fixed speed.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Good

The IM with VFD can be operated over a wide speed range, but the system efficiency drops considerably at light load and low speed.

PERMANENT MAGNET MOTOR

Excellent

The rare earth permanent magnet motor operates across a wide speed and torque range while maintaining high efficiency.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Very Good

A challenge in the design of the airgap channels is to combine optimization of reluctance with mechanical strength to endure the forces at high rotational speeds, especially for larger machines.

Temperature Handling Capability

TURNTIDE SMART MOTOR

Excellent

Owing to the ease of heat extraction and a rotor that is free of copper and permanent magnets, Turntide is capable of handling significantly higher temperatures.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Good

The inability to effectively extract heat from the rotor bars are a limiting factor in the thermal capabilities of the IM.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Good

The inability to effectively extract heat from the rotor bars are a limiting factor in the thermal capabilities of the IM.

PERMANENT MAGNET MOTOR

Poor (magnets)

The permanent magnetics restrict high temperature operation. Elevated temperature operation leads to a cascading failure as the magnetic strength decreases and additional current is required to compensate, thereby increasing losses and further reducing performance.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Excellent

Owing to the ease of heat extraction and a rotor that is free of copper and permanent magnets, the SynRM is capable of handling significantly higher temperatures. However, the distributed winding has higher losses than the Turntide motor leading to greater temperature restrictions.

Problems with Bearing Currents

TURNTIDE SMART MOTOR

Excellent

Exhibits robust operation and is immune to bearing currents/faults from common mode voltages.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Excellent

This is not an issue for an IM without a VFD.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Poor

This is an issue for an IM with a VFD because of the common mode currents induced in the motor shaft.

PERMANENT MAGNET MOTOR

Poor

This is an issue for the permanent magnet motor because of the common mode currents induced in the motor shaft.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Poor

This is an issue for the SynRMs because of the common mode currents induced in the motor shaft.

Material Cost

TURNTIDE SMART MOTOR

Excellent

With no exotic materials or processes involved in manufacturing, the Turntide motor has the lowest material cost.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Good

The material costs are relatively low, but the distributed windings and rotor bar casting/insertion add to manufacturing complexity and thus costs. Additionally, high efficiency IMs use cast copper vs. cast aluminum which impacts cost.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Good

The material costs are relatively low, but the distributed windings and rotor bar casting/insertion add to manufacturing complexity and thus costs. Additionally, high efficiency IMs use cast copper vs. cast aluminum which impacts cost.

PERMANENT MAGNET MOTOR

Poor

Permanent magnets add significant cost to the motor price. Use of SmCo or AlNiCo have high temperature capability, but lower energy densities and increase cost. Use of Ceramic magnets can lead to lower cost motors, but they typically have lower output torque due to lower flux densities.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Very Good

The material costs are on par with Turntide, but the distributed windings add to manufacturing complexity and thus costs. Additionally, there is a slight increase for rotor lamination costs due to their complexity.

Supply Chain Volatility

TURNTIDE SMART MOTOR

Excellent

There are no rare earth materials which create supply chain volatility.

STANDARD INDUCTION MOTOR (IM) W/ NO VFD

Excellent

There are no rare earth materials which create supply chain volatility.

STANDARD INDUCTION MOTOR (IM) W/ VFD

Excellent

There are no rare earth materials which create supply chain volatility.

PERMANENT MAGNET MOTOR

Poor

Motors which use NdFeB permanent magnets, containing rare-earth materials, will create supply challenges for five rare earth metals (dysprosium, neodymium, terbium, europium and yttrium). These materials are expected to create major problems in the years ahead.

SYNCHRONOUS RELUCTANCE MOTOR (SYNRM) W/VFD

Excellent

There are no rare earth materials which create supply chain volatility.