Siemens SINAMICS S120 AC frequency converter

The official hardware manual of Siemens SINAMICS S120 AC frequency converter focuses on modular multi machine transmission systems, covering system overview, grid side/motor side components, power modules, DC bus components, control units, encoders, accessories, cabinet EMC design, and maintenance processes. It specifies the Blocksize and Chassis structures, standardizes safe operation, wiring, installation, heat dissipation, selection, and fault handling, supports 200/400V voltage and 0.12-1193kW power, and relies on DRIVE CLiQ to achieve automatic component recognition, meeting the high dynamic and high-precision driving needs of machine tools, textiles, printing, wind power, and other industries.

Basic positioning and application

Product Series: SINAMICS S120 Modular AC Drive System

Applicable scenarios: High dynamic/high-precision single axis and multi axis equipment such as machine tools, printing, packaging, textiles, wind power, and conveying

Voltage level: single-phase/three-phase 200~240V, three-phase 380~480V

Power range: 0.12kW~1193kW

Structural form:

Blocksize: Compact, 0.12~90kW

Chassis: Rack type, 110~250kW and above

​System composition

1. Grid side components

Component function

Line filters suppress conducted interference and meet EMC C1~C4 requirements

Line reactors reduce harmonics, stabilize voltage, and resist voltage drops

Circuit breaker/fuse overload/short circuit protection, SCCR up to 200kA

Surge protector for power grid overvoltage protection

2. Power module (core)

PM240‑2：Blocksize，0.55~15kW， Built in rectifier and brake chopper

PM340：Blocksize，0.12~90kW， Supports single-phase/three-phase

Chassis: Rack mounted, 110-250kW, high power, strong overload

Common configuration: DC bus capacitor, pre charging, fan, DRIVE CLiQ interface

3. DC bus components

Braking unit: feedback braking energy, control bus voltage

Braking resistor: converts regenerative energy into thermal energy, equipped with a temperature control switch

Bus capacitor: energy storage and voltage stabilization, requiring regular molding and processing

4. Motor side components

Motor Reactor: Suppress dv/dt and Extend Motor Life

Sine wave filter: outputting an approximate sine wave to reduce motor noise

Dv/dt filter: limits voltage spikes and protects motor insulation

5. Control and Communication

Control unit: CU310-2 PN (PROFINET), CU310-2 DP (PROFIBUS)

Adapter: CUA31/CUA32, extended DRIVE CLiQ interface

Sensor module: SMC10/20/30, connected to various encoders

Communication bus: DRIVE CLiQ (automatic recognition) PROFINET、PROFIBUS

Safety and EMC specifications

security level

DANGER: Fatal risk (power outage, electrical testing, grounding)

Warning: Serious injury risk (ventilation, grounding, shielding)

CAUTION: Minor injury (high temperature, ESD)

NOTICE: Equipment damage

safety function

STO safety torque shutdown, safety brake relay, insulation monitoring

EMC Classification

C1: Civil environment

C2: Industrial/Civil Mixed

C3: Industrial environment (default)

C4: Heavy Industry

Installation and heat dissipation

Installation requirements

Must be installed vertically, inverted/horizontal is strictly prohibited

Reserved ventilation gap above and below: Blocksize 100~350mm, Chassis according to specifications

Reduction rules

Environmental temperature>40 ℃, altitude>1000m, switch frequency increase requires derating

Compensation for temperature decrease of * * 3.5 ℃ * * for every 500m increase in altitude

Wiring specifications

main circuit

Power grid: L1/L2/L3/PE, filter input and output must not be reversed

Motor: U2/V2/W2, shielded layer double terminal grounding

Braking resistor: DCP/R1, R2, cable ≤ 15m

control loop

24V power supply: PELV/SELV safety isolation

Grounding: PE is reliably connected, and the shielding layer is extensively grounded

Debugging and maintenance

Debugging tool: STARTER software, parameterization, firmware upgrade, monitoring

routine maintenance

Fan: Regular replacement, both PM240-2/PM340/Control Units have cooling fans

Capacitor: Long term storage requires molding treatment

Fault diagnosis: LED status light (READY/DC LINK/POWER OK), fault code query

Key issues

Question 1: What is the core function of the DRIVE CLiQ interface in S120? What are the advantages compared to traditional terminals?

Answer: DRIVE CLiQ is a Siemens dedicated high-speed communication interface that can automatically identify module models, parameters, and versions, and is plug and play; Simultaneously transmitting control data, status feedback, encoder signals, 24V power supply, simplifying wiring, reducing interference, and improving system reliability, without the need for manual configuration of addresses and jumpers.

Question 2: Why is it necessary to install the S120 power module vertically and maintain ventilation gaps? What consequences will violating lead to?

Answer: S120 adopts forced air cooling, and vertical installation ensures smooth airflow from bottom to top through the radiator; Ventilation gaps are used for heat dissipation and prevention of heat accumulation. Violation can lead to poor heat dissipation, excessive temperature, power module derating operation, IGBT overheating and burnout, significantly shortened lifespan, and trigger overheating fault shutdown.

Question 3: What key operation must be performed for S120 to be used in IT power grid (ungrounded system)? What are the risks of not executing?

Answer: The connection piece of the interference suppression capacitor must be removed. Failure to dismantle will result in capacitor leakage to the ground, breakdown of internal components in the module, short-circuit tripping, permanent damage to equipment, and non-compliance with IT grid safety regulations, leading to electric shock and fire risks.