Contactor 9A and M-Duino Industrial Arduino PLC

Example of use and application on how to control and industrial motor
April 3, 2019 by
Contactor 9A and M-Duino Industrial Arduino PLC
Serzh Ohanyan


In this post, we will show you an example of how to control a Motor with the Contactor 9A and one of our industrial Arduino controllers. You need to use a PLC with a relay output, so it's necessary to use our PLC Arduino Ardbox 20 I/Os RELAY HF or any of our M-Duino boards with a RELAY output.

Considering that we need to process a huge amount of data we will use an M-Duino controller since it has a faster processor than Ardbox (M-Duino are implemented with Mega, Ardbox with Leonardo) and an SD card to store data. 


M-Duino Family >>>

Ardbox Family >>>

Contactor 9A >>>

Contactor 9A


(Ue) Rated Operating Voltage

<= 300 V CC
<= 690 V AC 25...400 Hz

(Ie) Rated Operating Current 

25 A (<= 60 °C) at Ue <= 440 V CA AC-1
9 A (<= 60 °C) at Ue <= 440 V CA AC-3

[Ith] conventional free air thermal current

25 A at <= 60 °C for power circuit 
10 A at <= 60 °C for signalling circuit

(Ui) Rated Insulation Voltage

600 V

Electrical Durability

0.6 Mcycles 25 A AC-1 at Ue <= 440 V
2 Mcycles 9 A AC-3 at Ue <= 440 V

(Uc) Control Circuit Voltage

24 V DC

Mechanical Durability

30 Mcycles

[Uimp] rated impulse withstand voltage

6 kV conforming to IEC 60947

Overvoltage category


[Icw] rated short-time withstand current

105 A <= 40 °C 10 s power circuit
210 A <= 40 °C 1 s power circuit
30 A <= 40 °C 10 min power circuit
61 A <= 40 °C 1 min power circuit
100 A 1 s signalling circuit
120 A 500 ms signalling circuit
140 A 100 ms signalling circuit

Average impedance

2.5 mOhm at 50 Hz - Ith 25 A for power circuit

Power dissipation per pole

0.2 W AC-3
1.56 W AC-1

Control circuit voltage limits

0.1...0.3 Uc drop-out at 60 °C, DC
0.8...1.25 Uc operational at 60 °C, DC

Time constant

40 ms

Signalling circuit frequency

25...400 Hz

Minimum switching voltage/current

17 V / 5 mA for signalling circuit


77 mm


95 mm


45 mm


0,48 kg

As you can see in the image below, we connect the M-Duino controller to Vds at 24 V. Connect L1, L2 and L3 to the Three-phase Electrical Supply. Connect T1, T2, T3 to the Three-phase Motor. Finally, connecting a RELAY R.X (X = 1..8) output from the Arduino PLC to the Contactor 9A input +A1 and -A2 to the ground, we are able to enable and disable the three-phase Motor by a 24 V signal.

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Contactor 9A and M-Duino Industrial Arduino PLC
Serzh Ohanyan April 3, 2019
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