3‑Phase Motor Start with Siemens LOGO! program with timer and manual mode.
3‑Phase Motor Start with Siemens LOGO!
Basic control of a three‑phase induction motor using Siemens LOGO!, start/stop push buttons, contactor, and thermal overload relay. Suitable for small machines, fans, pumps, and workshop equipment.
Overview
This project demonstrates how to start and stop a three‑phase motor using a Siemens LOGO! controller. The motor is supplied from a 380 V three‑phase line through a contactor and overload relay, while the control circuit and LOGO! are powered from a 220 V AC supply. Start and stop push buttons are wired to LOGO! inputs, which control the motor contactor via a LOGO! output.
Power and control supply
• 380 V (R, S, T): feeds the motor through the contactor and overload relay.
• 220 V (L, N): feeds the LOGO! and the control circuit (push buttons, coil control).
Inputs & outputs
Inputs & outputs
Inputs (LOGO!):
• I1 – Start button (green, NO)
• I2 – Stop button (red, NC)
• I3 – Thermal overload relay contact (NC)
Output (LOGO!):
• Q1 – Contactor coil control (drives the three‑phase motor)
Safety Notes
Working with electrical installations involves a risk of serious injury, fire, or equipment damage.
If you do not have the required qualifications or experience, do not perform electrical wiring or modifications yourself.
Always consult or hire a qualified electrician.
The author of this project assumes no responsibility for incorrect wiring, damage, incidents, or any consequences resulting from the use of this information.
All diagrams and descriptions are provided for educational purposes only.• The overload relay must always be wired in series with the stop/safety chain.
Expansion options
• Add door safety switch in series with I3.
• Add run feedback from contactor auxiliary contact.
• Add motor running indication lamp.
• Add LOGO! display text (RUN/STOP, fault).
• Add timer for delayed start or automatic stop.
What you get
A complete, ready-to-use Siemens LOGO! motor start control example.
Includes clean logic, clear wiring concept, and a structured explanation of how the system works.
Ideal for learning, testing, or integrating into small machines and workshop equipment.
• Start/Stop control using NO/NC push buttons
• Contactor coil control via LOGO! output
• Thermal overload relay integrated into the safety chain
• Self‑latching (holding) logic for continuous motor operation
• Clear separation between 380 V power circuit and 230 V control circuit
• Expandable design: timers, interlocks, indicators, HMI text
• Fully editable logic for customization and training
The downloadable project package will be available soon.
It will include:
• Siemens LOGO! program file (.lpp)
• Wiring diagram in PDF format
• Input/Output list
• Logic description document
• Notes for integration and customization
