Siemens Micromaster 420 Drive


The MICROMASTER 420s are a range of frequency inverters for controlling the speed of three phase AC motors. The various models available range from the 120 W single-phase input to the 11 kW three-phase input.
The inverters are microprocessor-controlled and use state-of-the-art Insulated Gate BipoIar Transistor (IGBT) technology. This makes them reliable and versatile. A special pulse-width modulation method with selectable Pulse frequency permits quiet motor operation. Comprehensive protective functions provide excellent inverter and motor protection.
The MICROMASTER 420 with its default factory settings, is ideal for a large range of simple motor control applications. The MICROMASTER 420 can also be used for more advanced motor control applications via its comprehensive parameter lists.
The MICROMASTER 420 can be used in both ‘stand-alone’ applications as well as being integrated into ‘Automation Systems’.


The MICROMASTER 420 inverter is suitable for a variety of variable-speed drive applications.

It is especially suitable for applications for pumps, fans and conveyor systems.

It is the ideal cost-optimized frequency inverter solution. The inverter is especially characterized by its customer-oriented performance and ease-of-use. Its large supply-voltage range enables it to be used all over the world.


The MICROMASTER 420 has a modular design. The operator panels and communication modules can be easily exchanged without requiring any tools.

Main characteristics
  • Easy, guided start-up
  • Modular construction allows maximum configuration flexibility
  • Three fully programmable isolated digital inputs
  • One scalable analog input (0 V to 10 V) can also be used as a 4th digital input
  • One programmable analog output (0 mA to 20 mA)
  • One programmable relay output
    30 V DC/5 A, resistive load
    250 V AC/2 A, inductive load
  • Low-noise motor operation through high pulse frequency, adjustable (observe derating if necessary)
  • Complete inverter and motor protection
Options (overview)
Options (overview)
  • EMC filter, Class A/B
  • LC filter
  • Line commutating chokes
  • Output chokes
  • Gland plates
  • Basic Operator Panel (BOP) for parameterizing the inverter
  • Advanced Operator Panel (AOP) with multi-language plain text display
  • Asian Advanced Operator Panel (AAOP) with Chinese and English plain text dis­play
  • Cyrillic Advanced Operator Panel (CAOP) with Cyrillic, German and English plain text display

Image result for MicroMaster 420

Siemens Micromaster 420 Drive

Technical specifications

Technical data


Mains voltage and power ranges

200 V to 240 V 1 AC ±10 %

0.12 kW to 3 kW

200 V to 240 V 3 AC ±10 %

0.12 kW to 5.5 kW

380 V to 480 V 3 AC ±10 %

0.37 kW to 11 kW

Power frequency

47 Hz to 63 Hz

Output frequency

0 … 650 Hz, (limitation to 550 Hz in production to comply with legal requirements) 1)

Power factor

≥ 0.95

Inverter efficiency

96 % to 97 % (Further information is available on the Internet at:

Overload capability

Overload current 1.5 x rated output current (i.e. 150 % overload capability) for 60 s, cycle time 300 s

Inrush current

Less than rated input current

Control method

Linear V/f characteristic; quadratic V/f characteristic; multipoint characteristic (programmable V/f characteristic); flux current control (FCC)

Pulse frequency

16 kHz (standard with 230 V 1/3 AC)
4 kHz (standard with 400 V 3 AC)
2 kHz to 16 kHz (in 2 kHz steps)

Fixed frequencies

7, programmable

Skip frequency ranges

4, programmable

Setpoint resolution

0.01 Hz digital
0.01 Hz serial
10 bit analog

Digital inputs

3 fully programmable isolated digital inputs; switchable PNP/NPN

Analog input

1, for setpoint or PI controller (0 V to 10 V, scaleable or for use as 4th digital input)

Relay outputs

1, programmable, 30 V DC/5 A (resistive load); 250 V AC/2 A (inductive load)

Analog output

1, programmable (0 mA to 20 mA)

Serial interfaces

RS-485, optional RS-232

Motor cable lengths

  • without output choke

max. 50 m (shielded)
max. 100 m (unshielded)

  • with output choke

see variant dependent options

Electromagnetic compatibility

Inverter available with internal EMC filter Class A; available as options are EMC filters to EN 55 011, Class A or Class B


DC braking, compound braking

Degree of protection


Operating temperature

–10 °C to +50 °C (+14 °F to +122 °F)

Storage temperature

–40 °C to +70 °C (–40 °F to +158 °F)

Relative humidity

95 % (non-condensing)

Installation altitude

Up to 1000 m above sea level without derating

Standard SCCR
(Short Circuit Current Rating) 2)

100 kA

Protection features for

• Undervoltage

• Overvoltage

• Overload

• Earth faults

• Short circuit

• Stall prevention

• Locked motor protection

• Motor overtemperature

• Inverter overtemperature

• Parameter interlock

Compliance with standards

UL, cUL, CE, c-tick

CE marking

Conformity with low-voltage directive 73/23/EEC

Cooling-air volumetric flow required, dimensions and weights
(without options)

Frame size (FS)

Cooling-air volumetric flow required (l/s)/(CFM)

H x W x D (mm)

Weight, approx. (kg)



173 x 73 x 149




202 x 149 x 172




245 x 185 x 195


Cubic Feet per Minute

Product manuals

# File Description Date added File size Downloads
1 pdf 420_PLi_24525275_en_1006 09/27/2017 14:55 4 MB 188