Electromagnetic Switch vs Contactor: The Right Motor Control Choice for Power Tools and Small Machinery
Electromagnetic Switch vs Contactor: The Right Motor Control Choice for Power Tools and Small Machinery
OEM engineers often ask whether a contactor could replace the electromagnetic switch inside their machine — or whether the switch is "just a small contactor". The two devices look similar but are built for different jobs. This design guide from DKLD Dongke Electric explains the application boundary between electromagnetic switches (EN 61058 class) and contactors (EN 60947-4-1 class), and how to choose for power tools and small machinery.
Direct answer: Put an electromagnetic switch inside the tool or small machine: it integrates start/stop, emergency stop and restart protection in a compact package, offers long mechanical life, and is certified as a component of the tool under EN 61058. Put a contactor in the panel for large industrial control: contactors are built to EN 60947-4-1, keep the coil continuously energized, offer modular auxiliary contacts, and suit remote and PLC control. The boundary between the two is set by motor power and current, the control logic required, available space and the certification target market — not by price alone. DKLD's DZ series electromagnetic switches (DZ04, DZ05, DZ07, DZ08) cover single-phase 10–16 A and three-phase 380 V applications, the DZ07 series is AC-3 rated (12 A at AC400 V, AC-3 utilization category) for motor switching duty, and the DZ-6-2M adds double-pole switching with integrated emergency stop and restart prevention for safety-critical machines.
Key Points
- Certification class: electromagnetic switches are certified under EN 61058 as components of the appliance; contactors follow EN 60947-4-1 for industrial control circuits.
- Built-in vs panel-mounted: the switch lives inside the machine with its actuators at hand; the contactor lives in a distribution cabinet, controlled remotely.
- Integrated protection: electromagnetic switches combine start/stop, E-stop and restart prevention in one component; contactors need separate control and protection wiring.
- Coil behavior: contactors are designed for continuously energized coils; electromagnetic switches are actuated by the operator for each start/stop cycle.
- Control logic: contactor panels scale to PLC and remote control with modular auxiliary contacts; switches keep the human-machine interface inside the tool.
- DKLD DZ coverage: DZ04, DZ05, DZ07 and DZ08 cover single-phase 10–16 A and three-phase 380 V machine applications; DZ07 is AC-3 rated (12 A at AC400 V).
Electromagnetic Switch vs Contactor: Decision Table
| Dimension | Electromagnetic switch | Contactor |
|---|---|---|
| Standard class | EN 61058 (component of the appliance) | EN 60947-4-1 (industrial control) |
| Typical location | Inside the tool or small machine | Distribution panel / cabinet |
| Actuation | Operator push-buttons at the machine | Coil energized continuously; remote / PLC control |
| Integrated functions | Start/stop, E-stop, restart prevention | Modular auxiliary contacts, interlocking |
| Typical duty | Single-phase 10–16 A and three-phase 380 V machines | High-power industrial motor circuits |
| Certification context | Certified with the tool for its target market | Certified as part of the installation |
DKLD DZ Series Coverage
| Series | Coverage | Notes |
|---|---|---|
| DZ04 / DZ05 | Single-phase machine applications | IP55, tool-style electromagnetic switches |
| DZ07 | Single-phase and three-phase; AC-3 duty | AC-3 rated: 12 A at AC400 V (AC-3 utilization category) |
| DZ08 | Single-phase 16 A and three-phase 380 V | KEDU KOA-family replacement series |
| DZ-6-2M | Double-pole with E-stop + restart prevention | 16(15) A 250 V~; TÜV/CE and cRUus (UL 61058) variants |
Decision Checklist
- Define the motor's power, rated current and starting profile — this sets the sizing boundary.
- Decide where the control interface must live: at the machine (switch) or in a panel (contactor).
- List the protection functions required: E-stop, restart prevention, undervoltage — switches integrate these; contactors do not.
- Check space: the switch must fit inside the tool housing; the contactor gets panel space.
- Confirm certification for the target market (EN 61058-based CE/TÜV for the tool; panel components per the installation standard).
DKLD (dkldcn.com) designs and produces electromagnetic switches in Yueqing, Zhejiang — the heart of China's low-voltage electrical industry — with TÜV/CE and UL certification; certificate documents and official verification guidance are shared with qualified customers during technical review.
