Kollmorgen AKD/S700 series servo drive

Kollmorgen AKD/S700 series servo drive

In the field of modern industrial automation and precision motion control, the performance, reliability, and electromagnetic compatibility (EMC) of servo drive systems are crucial. Kollmorgen's AKD and S700 series digital servo drives, as mainstream solutions in the market, rely not only on the drives themselves but also on a complete and compliant accessory ecosystem for their outstanding performance. This article is based on the official AKD/S700 Parts Guide and combines a systems engineering perspective to deeply analyze the technical principles, selection criteria, installation specifications, and optimization strategies of key components. The aim is to provide a complete integration framework from theory to practice for system integrators and equipment manufacturers.

Chapter 1: Overview of System Architecture and Core Components

A complete digital drive system is much more than just drivers and motors. The system architecture varies depending on the application voltage and power level:

Low voltage systems (AKD-P00306 to 02406) typically require an external main power filter to meet EMC standards, and may be equipped with motor reactors to suppress long cable effects.

High voltage systems (AKD-P00307 to 02407 and S700 series): Most have built-in filters, but high-power models (such as S748/S772) must have an external main power reactor to prevent abnormal DC bus voltage rise (up to 800V) when the grid asymmetry exceeds 3%.

Core accessory categories: System construction requires comprehensive consideration of mechanical installation tools, shielding and grounding accessories, power conditioning devices (filters/reactors), braking/regenerative energy processing modules, motor reactors, and various communication and power cables.

Chapter 2: Electromagnetic Compatibility (EMC) and Shielding Grounding Practice

EMC is the lifeline for the stable operation of industrial drive systems, and improper shielding and grounding are the root causes of the vast majority of interference problems.

1. Composition of shielding system:

Shielding board: Specific models of drivers (such as AKD-z-00307/00607/01207) come with dedicated shielding boards for guiding and concentrating the grounding cable shielding layer, forming a low impedance high-frequency noise discharge path.

Shielding clip: It is recommended to use brands such as Phoenix Contact SK14 (6-13mm tension range) and clip it into the reserved slot on the front panel of the drive to ensure extensive contact with the metal panel.

External shielding busbar: In multi axis or complex systems, brass busbar (section 10x3mm) can be used for centralized grounding. During installation, metal spacing columns should be used to maintain a distance of 50mm from the ground, and at least 2.5mm ² wires should be used for single point grounding to the main grounding bar of the cabinet.

2. Grounding philosophy:

Separation of high-frequency noise and safety grounding: The shielding system deals with high-frequency interference at the MHz level, requiring low inductance and large-area contact; And safety (PE) is related to personal safety and must comply with the standard wire diameter. The two should converge at the star shaped grounding point of the system.

Cable shielding layer treatment: All shielding layers must be connected in a 360 degree loop at the driver and motor ends. Use metalized connector housings or shielding clips to avoid using "pig tail" single point leads, which can exhibit high impedance at high frequencies.

Chapter 3: Power Conditioning and Energy Management

The quality of the power supply directly affects the lifespan and performance of the driver.

1. Main power reactor:

Function: Suppress rapid current rise caused by commutation and protect semiconductors; Reduce voltage drop in the power grid; Smooth the ripple current of the DC link and extend the lifespan of the capacitor.

Selection: Multiple drivers can share one reactor, and its rated current must be greater than or equal to the total current of the connected drivers. For example, when the power grid is asymmetric, the S748/S772 requires the use of 3L series reactors with a short-circuit voltage of 2% (uk).

2. Selection and calculation of main power filter:

For AKD models that require an external filter, power verification is required for selection:

Maximum throughput capacity of the filter: P_maxF=√ 3 * U-N * I2 * NF

Maximum power consumption of the driver: P_maxV=g * √ 3 * U-N * ∑ (IpeakVi)

Maximum feedback power of motor: P_maxM=g * ∑ (k_Ei * n_i/1000 * IpeakFi * √ (3/2))

The rated current of the filter, I2 NF, must simultaneously meet the following requirements: I2 NF ≥ 2 * ∑ (I2 NF) and I2 NF ≥ P_maxM/(√ 3 * U-N). Where g is the simultaneous coefficient and k_E is the motor back electromotive force constant.

3. Regenerative energy treatment plan:

The regenerative energy generated during motor deceleration must be properly handled, and there are three solutions:

Braking resistor: converts energy into heat and dissipates it. Kollmorgen offers BAFP (U), BAR (U), and BAS (U) series, with differences in protection level (IP20/IP40) and installation method. The selection should be based on matching the braking power, duty cycle, and resistance value. Warning: The surface temperature of the resistor can exceed 250 ° C and must be installed on a non combustible surface with sufficient heat dissipation space.

Capacitive Module (KCM): A high-end solution for energy recovery.

KCM-S (energy-saving type): stores braking energy for the next acceleration, reducing peak power consumption.

KCM-P (power down protection type): Provides the energy required for controlled shutdown of the drive in the event of a main power failure.

KCM-E (Extended): Increase the total energy storage capacity of the system.

Safety warning: The DC bus voltage can reach up to 900V. After power failure, it is necessary to confirm that the voltage is below 40V before operation. The module may self discharge for more than 1 hour.

Chapter 4: Motor Cables, Reactors, and Long Distance Transmission

The high-frequency PWM voltage output by the frequency converter will generate capacitive coupling current between the phase line and shielding layer of the motor cable.

1. The necessity of motor reactors:

When using shielded motor cables with a length exceeding 25 meters, motor reactors (such as 3YLN series) must be installed. Its function is to:

Reduce the current change rate (di/dt) to decrease the capacitive displacement current.

Suppress voltage reflection and overshoot at the motor end, and protect the motor insulation.

Reduce motor current ripple and improve operational stability. The reactor should be installed near the driver.

2. Balance of cable cross-section:

Using smaller cross-sections (such as 4x1.0mm ²) for long cables (>50m) can increase line resistance and help dampen LCR resonant circuits composed of drivers, reactors, cables, and motors.

But it is necessary to ensure that the current carrying capacity of the cable always meets the EN 60204 standard and takes into account voltage drop.

Chapter 5: Cable System: Wiring Standards and Specifications Production

Cables are the blood vessels for signal integrity and system safety.

1. Voltage level and wiring specifications:

Key standards: UL 508C, UL 508A, and NFPA 70 (NEC) section 300.3 (C) (1) stipulate that the insulation level of all wires in the same trunking, cable, or conduit must not be lower than the highest circuit voltage that any conductor in that space can withstand.

Practical significance: This means that "economical" feedback cables rated at 300V, if laid in parallel with power cables with voltages higher than 300V, are non compliant. At this time, a "performance type" cable rated at 600V should be selected or the two should be physically isolated.

2. Advantages of prefabricated cables:

Kollmorgen offers complete pre assembled cables, such as VP series power cables and VF/CF series feedback cables, with advantages including:

Compliant with CE/UL standards to ensure safety and EMC performance.

Accurately match the connector to avoid poor contact.

The shielding layer has been professionally terminated. The specifications cover different current levels (3/6A, 12A, 24A), whether brake lines are included, and various feedback types (incremental, EnDat, Resolver, Hiperface, etc.).

3. Key points for on-site cable production (taking S701-724 power cable as an example):

Peel off about 120mm of outer sheath, do not damage the shielding woven mesh.

Fold the shielding net backwards and secure it with a rubber sleeve or heat shrink tubing.

All wire cores (except for the yellow green PE wire) are truncated by about 20mm to make the PE wire the longest.

The shielding layer is fixed on the driver shielding cover with cable ties or hose clamps to achieve large-area contact.

After crimping the pins of the wire core, insert the connector according to the wiring diagram, and finally tighten the connector housing to ensure shielding connection.

Chapter 6: Communication and Feedback Interface Accessories

Stable and reliable communication is the foundation of distributed motion control.

1. CANopen bus:

Cable: A specialized twisted pair shielded cable with a characteristic impedance of 120 Ω is required. The transmission rate is related to the maximum cable length (e.g. 1Mbps corresponds to 25m, 100kbps corresponds to 1000m).

Terminal resistor: The AKD driver at the end of the bus must be equipped with a terminal resistor plug (P-AKD-CAN-TERM) to eliminate signal reflection.

Adapter: Provides RJ12 to Sub-D9 adapter for easy connection to standard CANopen controllers.

2. Production of feedback cables (using a Parser as an example):

Use shielded twisted pair cables (recommended to follow DIN 47100 color code), with a maximum length of 100 meters (for extra long cables, please consult technical support).

The welding of the 12 pin connector at the motor end must strictly follow the pin definitions, usually including R1/R2 (excitation), S1/S2 (sine), S3/S4 (cosine), and thermistor signals.

The shielding layer is connected in a 360 degree loop at the driver end through the Sub-D connector housing.

Chapter 7: Mechanical Installation and Safety Regulations

1. Safety first:

Qualifications: Transportation, installation, wiring, and debugging must be carried out by professionals with corresponding qualifications.

Power off operation: After the main power supply is disconnected, the dangerous voltage at the power terminals may remain for more than 10 minutes. Before operation, it is necessary to verify that the phase to ground and phase to phase voltages have disappeared.

Capacitor discharge: DC bus capacitor energy storage is dangerous. After power failure, it is necessary to wait for its self discharge or use special tools to discharge to a safe voltage (<40V) before contacting.

2. Heat dissipation and spacing:

Drivers, braking resistors, and reactors all generate heat during operation. Installation needs to ensure sufficient space in the top, bottom, left, and right directions (see dimension diagram) to ensure unobstructed airflow.

High temperature resistant components must be used around the braking resistor, and it is strictly prohibited to arrange wiring terminals or other equipment on the hot air path.

3. Special tools:

Suspension unit: used for installing heavy-duty motors (such as AKM8, maximum 120kg), strictly follow the safety instructions in its separate manual.

Side mounted clamp: It is allowed to install the S701-712 (70mm clamp) or S724 (100mm clamp) driver onto the side wall or door panel of the control cabinet.

Chapter 8: System Debugging, Maintenance, and Troubleshooting Framework

1. Pre debugging check:

Verify that all accessory models match the driver and motor.

Check all electrical connections for tightness and ensure reliable shielding connections.

Confirm that the grounding system complies with EMC and safety regulations.

2. Common fault clues:

Communication failure: Check cable model, terminal resistance, PC grounding, and baud rate settings.

Overvoltage fault: Check whether the resistance and power of the braking resistor match, whether the braking ramp time is too short, and consider parallel connection of the DC bus for multi axis systems.

Driver malfunction: Check for short circuits/grounding in motor cables, motor insulation, and good heat dissipation conditions.

3. Maintenance and scrapping:

The drive is designed to be maintenance free, and unauthorized opening of the housing will result in the warranty being invalidated.

When cleaning, only use isopropanol to wipe the shell, do not spray or soak.

When scrapped, professional recycling companies should dismantle and separate components such as aluminum radiators, steel shells, electronic circuit boards, etc. for environmental protection treatment.