Pacific Scientific POWERMAX II stepper motor

Performance curve and acceleration comparison

POWERMAX II provides a complete torque speed curve (the curve is not directly printed in the document, but it is mentioned that it can be obtained through optimizer 3.0 software). Generally speaking, double stack motors have higher holding torque and low-speed torque than single stack motors, but due to increased inductance, the torque decay at high speeds is faster. Low inertia rotors perform better at high speeds because their lower rotational inertia allows for faster acceleration.

The document provides a comparison of theoretical normalized acceleration (based on no-load, 90 ° C temperature rise, bipolar drive):

Motor model, rotor type, inertia (oz-in-s ² × 10 ³), normalized acceleration

P21NRXX standard L 1.68 1.00

P21NRXX low inertia J 1.30 1.27

M21NRXX standard L 1.68 1.23

M21NRXX low inertia J 1.30 1.59

P22NRXX standard L 3.57 1.00

P22NRXX low inertia J 2.59 1.30

M22NRXX standard L 3.57 1.18

M22NRXX low inertia J 2.59 1.63

It can be seen that when the M series using Sigmax technology is combined with a low inertia rotor, the acceleration can be increased by 59-63%, significantly improving the dynamic response of the system.

Customization capability and accessories

The "Design for Manufacturability" (DFM) concept of POWERMAX II enables it to achieve high customization at a lower cost:

Axis modification: flat, keyway, threaded hole, extended shaft, dual axis extension.

Integrated lead screw: It can be directly processed, rolled or ground on the motor rotor, eliminating the need for couplings and saving space.

Encoder installation: Incremental encoders (optical or magneto resistive) can be installed to achieve closed-loop control or position verification. Encoder options can be found on page 53 of the document.

Reducer: Can be equipped with a high-performance gearbox to increase output torque or change output speed.

Special winding: In addition to standard A-G windings, specific current/inductance combinations can be designed according to customer requirements.

Application scenarios and selection suggestions

Typical Applications

Electronic assembly equipment: SMT machines, dispensing machines, and flying needle testing machines require high acceleration and precise positioning.

Medical equipment: infusion pump, sample processing system, scanning table, requiring low noise and low vibration.

Packaging machinery: label machines, sealing and cutting machines, material conveying, require reliable open-loop control.

Laboratory automation: liquid processing workstation, microplate conveying, requiring compact size and long lifespan.

CNC machine tools: small carving machines, 3D printers, winding machines.

Selection steps

Determine torque demand: Calculate the required holding torque and dynamic torque based on load torque, acceleration torque, and friction torque.

Choose stack length: Single stack is suitable for medium torque requirements; Double stack provides higher torque but also greater inertia.

Choose series: If higher acceleration and efficiency are required, prioritize the M series (Sigmax); If cost is sensitive, the P series is sufficient.

Select rotor type: For applications with frequent start stop, choose low inertia (J) rotors; Select standard (L) rotors for smooth operation or high inertia loads.

Choose winding: Based on the output current and supply voltage of the driver, select the winding that can provide the required torque speed characteristics. Usually, low inductance windings are advantageous for high-speed operation.

Confirm mechanical interfaces: shaft diameter, shaft length, flat or keyway, installation hole position.

Consider accessories: do you need encoders, reducers, connectors, and cables.

Quality Assurance and Environmental Compliance

The POWERMAX II motor comes with a two-year warranty, demonstrating Pacific Scientific's confidence in product reliability. The motor adopts a new polymer encapsulated stator and a polymer end cap with threaded inserts, which improves heat dissipation performance and facilitates the installation of encoders or brakes. The exposed laminated structure helps to dissipate heat directly from the winding into the surrounding air. The motor meets the NEMA Class B insulation requirements and has passed the corresponding vibration and impact tests (specific standards need to refer to the complete manual).