SIGMATEK AKM Servo Motor Replacement and Troubleshooting Guide

SIGMATEK AKM Servo Motor Replacement and Troubleshooting Guide

In the field of industrial automation, equipment updates and system performance upgrades are the norm that engineers must face. When the original servo motor is discontinued, its performance deteriorates, or it cannot meet the high dynamic requirements of the new generation production line, finding an alternative solution that can perfectly match the original mechanical dimensions and electrical interfaces, while providing higher cost-effectiveness and reliability, becomes the key to the success of the project. The AKM series synchronous servo motors launched by SIGMATEK provide a highly valuable reference solution for the replacement and upgrade of old servo systems, thanks to their rich flange sizes from AKM1 to AKM7, high dynamic response characteristics, and highly flexible feedback and braking configurations.

The core driving force for replacement and selection: why choose the AKM series architecture

When replacing old servo motors, engineers typically face three major pain points: mechanical size mismatch, incompatible feedback systems, and inability to meet modern safety standards. The SIGMATEK AKM series provides highly flexible engineering options for these pain points.

1. Modular mechanical and electrical design

The AKM series synchronous servo motor adopts a brushless rotary converter design, specially designed for high-end servo applications. The rotor is made of neodymium magnet material with high dynamic performance, and the stator is a three-phase winding. Unlike traditional motors, the commutation of AKM motors is completed electronically in servo amplifiers, completely eliminating the hidden danger of brush wear. Its basic structure adopts the IM B5 configuration of DIN EN 60034-7 standard, with flange dimensions in accordance with IEC standards, a fit tolerance of j6 (h7), and accuracy in accordance with DIN 42955 tolerance level N, ensuring seamless replacement with the original gearbox or coupling.

2. Flexible feedback and braking options

When replacing an old motor, the compatibility of the feedback system is of utmost importance. The AKM series comes standard with a passive PTC thermistor (switch point 155 ° C ± 5%) and a rotary transformer (Resolver) as standard feedback units. At the same time, users can flexibly choose between EnDat encoders (single or multi turn, such as ECN 1113, ECN 1125) or HIPERFACE encoders (such as SKM 36) according to the requirements of the servo amplifier. For applications that require vertical axis holding torque, AKM2 to AKM7 models can be equipped with 24V DC spring applied brake. This highly modular design allows engineers to accurately match replacement requirements without changing the original control architecture.

3. Comprehensive compliance and certification

The AKM series motors comply with EG standards 2004/108/EG (electromagnetic compatibility) and 2006/95/EG (electrical equipment within specific voltage limits) and have passed UL certification (E515640). In the replacement project, the use of motors with compliance certification is a prerequisite for ensuring the safety acceptance of the entire machine.

Accurate selection and replacement calculation: avoid "small horses pulling big cars"

When determining the replacement plan, it is far from enough to rely solely on matching the appearance dimensions. The load must be recalculated to ensure that the performance of the new motor meets or even exceeds that of the original system.

1. Core selection parameters

The most important selection criteria include: static torque (M0), rated speed (nn), inertia torque of the motor and load (J), and calculated effective torque (Mrm). When selecting motors and servo amplifiers, both static loads and dynamic loads (acceleration/braking) must be considered simultaneously. The AKM series offers a wide range of choices, such as:

AKM1 series: flange size 40mm, static torque 0.18 to 0.41 Nm, suitable for micro precision equipment.

AKM4 series: flange size 84mm, static torque 1.95 to 6 Nm, suitable for medium-sized universal production lines.

AKM7 series: flange size 188mm, static torque 29.4 to 53 Nm, suitable for heavy-duty high inertia applications.

2. Rigorous environmental derating calculation

When replacing, the impact of ambient temperature on motor performance must not be ignored. According to the technical specifications, the motor needs to undergo a 1% power derating (current and torque) at an ambient temperature between 40 ° C and 50 ° C. If the installation altitude exceeds 1000 meters, it is necessary to reduce the rating according to the altitude: 6% for 2000 meters, 17% for 3000 meters, 30% for 4000 meters, and 55% for 5000 meters. If the altitude exceeds 1000 meters but temperature derating is carried out at the same time (10k derating per 1000 meters), there is no need for further derating. Engineers must calculate the actual working conditions when selecting replacement models to avoid the motor being in an overloaded state for a long time.

3. Rotational inertia and dynamic response

The rotor inertia torque (J) of an AKM motor is an important indicator for measuring its acceleration capability. Taking AKM1 as an example, its J value is only 0.017 to 0.045 kgcm ², which means it can achieve extremely fast acceleration. When replacing an old motor, if the inertia ratio of the new motor is too different from the original system, it may cause difficulty in setting the servo gain and even cause system oscillation. Therefore, it is recommended to control the ratio of load inertia to motor inertia within a reasonable range when replacing calculations.