LS ELECTRIC L7C AC Servo Systems

Drive Features

• Power: 100W-1kW single-phase 220VAC
• Fully digital with up to 1kHz velocity loop response
• Easy setup and diagnostics via built-in keypad/display or DriveCM PC-based software
• Field upgradeable firmware
• Command options: ±10V torque or velocity command, Pulse train or master encoder position command (accepts line driver or open collector) with real-time selectable electronic gearing
• Internal Indexer: 64 individual move statements configurable in the drive, initiated via Digital Inputs or serial comms.
• 1 kHz bandwidth for high-level automatic tuning. Modes include Off-Line Auto Tuning, On-Line Auto Tuning, and Manual Tuning.
• Optically isolated digital inputs (10), user-configurable outputs (5), permanently configured alarm/status outputs (3), analog inputs (2) for speed/torque control, and line driver output for encoder.
• Advanced Scope feature for monitoring command and status signals.

Motor Features

• Low inertia models: 100W, 200W, 400W, 750W, and 1kW
• Speeds up to 5,000 rpm
• Permanent magnet 3-phase synchronous motor
• Keyed drive shafts support clamp-on or key-style couplings
• Integrated 17-bit resolution encoder (131,072 pulses per revolution)
• Optional 24 VDC spring-set holding brakes (AYK2 motors)
• Standard hook-up cables for motor power, encoder, and brake (separate brake cable for brake motors)
• Motor cables available in standard or flex-rated lengths (3, 5, 10, 20m)
• Standard 50-pin DIN-rail mounted break-out kit for CN1 connector or 50-pin cables with flying leads.
• IP67 Housing

Tuning Technology

The L7C drive provides precise control of current, velocity, and position. Its 1kHz bandwidth ensures accurate speed and current control, simplifying tuning. Features include proportional gain, integral gain, feed forward compensation, low pass filter, and four notch filters for resonance suppression. Auto Tuning is enhanced to handle up to 20:1 inertia mismatch. An inertia estimation function analyzes motor and load inertia. Tuning methods include Online Auto Tuning, Offline Auto Tuning, and Manual Tuning.

Built-in Indexer

The L7C drives offer internal motion control, supporting 64 point-to-point position moves. These moves can be configured via DriveCM software or programmed by a PLC via RS422/485 serial port. Moves can be initiated by digital inputs or serial commands and sequenced with delays or linked together. This capability is suitable for applications like press feeds, rotary tables, robots, and assembly operations.

Optional Holding Brake

LS Electric L7C motors can be equipped with an optional 24 VDC spring-set holding brake that secures the motor when power is removed.

LS Electric MSS Series In-Line Planetary Precision Gearboxes

These gearboxes are designed to increase motor torque output and reduce reflected load inertia, improving system response. They offer high stiffness, efficiency, and quiet operation. Features include maintenance-free operation, IP65 rating, and a wide operating temperature range (-10°C to +90°C). Available in three gear ratios (5:1, 10:1, 20:1) with industry-standard mounting dimensions and very low backlash.

How to Select and Apply L7C Systems

Key considerations for selecting an AC servo system include reflected load inertia, maximum speed requirement, continuous torque requirement, and peak torque requirement. For new applications, these parameters should be determined through calculation and measurement. AutomationDirect offers free servo-sizing software, "VisualSizer-SureServo", which assists in calculating reflected load inertia and required speed/torque. It can be downloaded from https://support.automationdirect.com/products/sureservo.html.

Reflected Load Inertia: The total inertia of all components attached to the driveshaft, reflected to the motor shaft, must be considered. A low ratio of reflected load inertia to motor inertia (ideally under 10:1) is beneficial for high response applications. L7C Auto Tuning can handle up to 20:1 inertia mismatch.

Torque and Speed: Determine required continuous and peak torque, and maximum motor speed based on the motion profile and mechanical transmission. Compare these requirements against the system's torque-speed curves. The Drive CM software's Advanced Scope feature can help capture these values.

Mechanical Transmissions and Couplings

Common mechanical transmissions include leadscrews, rack & pinion, conveyors, gears, and timing belts. LS Electric offers matched gearboxes for FBL/FCL motors. Speed reducers like gearboxes or timing belts can reduce reflected load inertia, increase torque, and improve system performance. Coupling selection should consider stiffness, torque rating (with a safety factor of 1.25 over peak torque), and inertia. "Servo-grade" clamp-on or compression couplings are recommended.

Part Numbering System

The part numbering system for L7C drives and APMC motors follows a structured format indicating series, capacity, voltage, options, shaft end shape, encoder type, rated RPM, motor capacity, flange size, and motor shape.

Torque to L7C System Quick Reference

L7C AC Servo Drive, Motor, and Cable Combinations

Detailed tables provide combinations of L7C Drives, APMC Motors (including brake and non-brake variants), Power Cables, Encoder Cables, and Brake Cables for various system torque ratings and speeds.

Motor Specifications

Non-brake Motor Specifications

Brake Motor Specifications

Accessories

CN1 Accessories

Two methods for creating I/O connections for L7x series drives:

• Option 1: Terminal blocks + cables (e.g., APC-VSCN1T-AD).
• Option 2: Flying lead cables (e.g., APC-CN101A-AD).

Note: For L7C drives using PLC/Drive serial communication, use APC-CN10xA-AD flying lead cables to avoid communication errors.

Motor Encoder Cables

Motor Brake Power Cables

Motor Power Cables

LS Drive System Replacement Connectors

System Braking Resistors

Note: 600W resistors require customer-supplied M5-.8 bolts and cable lugs for connection.

System Planetary Gearboxes

Precision planetary gearboxes enhance servo system torque output and reduce reflected load inertia. They offer high stiffness, efficiency, and quiet operation. Features include maintenance-free operation, IP65 rating, and a wide operating temperature range (-10°C to +90°C).

Note: Service life is 20,000 hours (10,000 under continuous operation).