Electric Actuator for On-Off Type Valve
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Electric Actuator for 1/4 Turn Valve — On-Off Type, ISO5211, IP67, NEMA 4X/5, 15 to 500 NM
Cematic's On-Off electric valve actuator is the standard device for operating 1/4 turn ball and butterfly valves without manual intervention. Its On-Off function executes only two positions — fully open or fully closed.
Therefore, it is the right choice for cut-off and isolation systems where flow regulation is not required. It is also available in torques from 15 to 500 NM to cover ball and butterfly valves in any application diameter.
Its aluminum alloy cover with powder polyester coating also complies with corrosivity category C3 according to ISO 12944-2. Consequently, it is suitable for outdoor use and industrial installations with moderate exposure to corrosive environments.
Cematic also delivers the actuator assembly pre-assembled and calibrated to the valve, ready for installation.
On-Off Type — what it means and when it's right
The On-Off electric actuator operates in only two positions: fully open or fully closed. Upon receiving an electrical signal, the actuator rotates 90° to the corresponding position and stops. When the signal is cut or reversed, it returns to the opposite position. The following describes cases where the On-Off type is the standard option:
- Isolation and shut-off systems: When the valve acts as a sectional element — opening or closing a complete line — without the need for intermediate positioning. It is also the simplest configuration to integrate into a PLC without the need for an analog signal.
- Automatic process cycles: In processes with programmed opening and closing sequences — filling, emptying, bypass — the actuator executes each operation with precision and repeatability. This reduces operational errors and eliminates the need for manual intervention in each cycle.
- Emergency and safety systems: The On-Off actuator can be configured to bring the valve to a safe state — open or closed — in the event of a power outage. Consequently, it protects the process from control system failures. Consequently, it protects the process from control system failures.
When it is necessary to position the valve at intermediate angles to regulate flow, however, a modulating actuator must be specified. See Modulating electric actuator →
Torque selection
The actuator torque must be greater than the valve's operating torque at maximum working pressure. The available range is described below:
- T15 — 15 NM: For very small diameter ball and butterfly valves in low-pressure services.
- OM1 — 35 NM: For ball and butterfly valves in 1/2" to 2" diameters in standard services. It is also the entry torque for the OM range.
- OMA / OMAM — 50 NM: For valves in 2" to 3" diameters. The OMA model does not include manual override; the OMAM, however, includes an integrated lever.
- OM2 — 90 NM: For intermediate diameter valves from 2" to 4" or higher pressure valves requiring more torque. It also includes a manual override handwheel and adjustable mechanical stops.
- OM3 — 150 NM: For 4" to 6" butterfly valves or larger diameter ball valves at high pressure. It also includes a handwheel and mechanical stops.
- OM4 — 400 NM and OM5 — 500 NM: For large diameter valves or at high differential pressure. Therefore, these are the standard torques in industrial lines from 6" to 12".
If higher torques are required, as well as verification of torque-valve compatibility, consult Cematic's technical team.
Actuator technical features
The self-locking steel gear system also eliminates angular play. This ensures that the valve remains in the commanded position without continuous current. The gears are also factory-lubricated for the entire life of the actuator, so they do not require transmission system maintenance.
The motor also includes integrated thermal protection that prevents damage from overheating in frequent operating cycles. Finally, all models include an externally visible mechanical position indicator. This makes it possible to verify the valve's status without accessing the control system.
Technical specifications
| Parameter | Value |
|---|---|
| Control type | On-Off (full open/close) |
| Movement type | 1/4 turn (90°) |
| Available torques | 15 / 35 / 50 / 90 / 150 / 400 / 500 NM |
| Available voltages | 12 VDC / 24 VDC / 24 V AC/DC / 110 V / 220 V |
| Housing | Aluminum alloy, powder polyester coating |
| Protection | NEMA Type 4X / 5, IP67 |
| Mounting | ISO5211 |
| Standard duty cycle | 30% |
| Ambient temperature | -30 °C to +65 °C |
| Relative humidity | 30% to 95% |
| Conduit entries | 1/2" NPT |
| Position indicator | Mechanical, included in all models |
| Manual override | Lever (OM1, OMAM) / Handwheel (OM2 to OM5) / No override (OMA) |
| Corrosion protection design | ISO 12944-2 Category C3 |
| Compatible with | ISO5211 ball and butterfly valves |
Voltage selection
24 VDC or 24 V AC/DC voltage is standard in cabinets with PLCs and DC power supplies. Therefore, it is the most common option in new installations. 110 V voltage, however, is for installations with 110 V circuits available in the field.
Finally, 220 V voltage is for panels with bi-phase distribution. Voltage availability varies by torque model, so it is recommended to check with Cematic's technical team before specifying.
Manual override — operation without power
Models OM1, OMAM, and OM2 to OM5 also include a manual override to operate the valve in the event of a power outage. The handwheel or lever also does not rotate during normal electrical operation. Therefore, the operator is not at risk of contact with moving parts.
Consequently, manual emergency operation is safe without needing to disconnect the actuator from the system. The OMA model does not include a manual override, so it is recommended for installations with guaranteed power supply.
Applications of the On-Off electric actuator
Flow Control in Chemical Processes
The On-Off electric actuator allows for quick and remote cut-off and opening of chemical flow. The electrical signal from the PLC also performs the operation without exposing the operator to the chemical. Consequently, it improves operational safety and process efficiency in plants with hazardous or aggressive fluids.
HVAC Systems and Water Treatment
In HVAC systems and water treatment plants, this actuator also controls the opening and closing of zone, bypass, and sectional valves. Its direct integration with the PLC or installation controller also allows for remote operation without manual intervention. Therefore, it is the standard component in the automation of HVAC and water distribution systems.
Food and Pharmaceutical Industry
In food and pharmaceutical production lines, the On-Off actuator also executes opening and closing cycles in automated process sequences. The ISO5211 mounting also guarantees direct compatibility with Cematic's hygienic valves. Consequently, Cematic delivers the valve + actuator assembly pre-assembled and calibrated, ready for installation without field integration work.
Refineries, Petrochemical, and Power Generation
In continuous process installations, this actuator also handles line cut-off, flow diversion, and safety valve operation. Its IP67 and NEMA 4X protection also ensures reliable operation outdoors and in demanding industrial environments. Therefore, it is the standard automation component in plants where system availability is a critical requirement.
Irrigation Systems and Process Automation
In mechanized irrigation systems and process automation, this actuator also allows for remote programming of cycles from the control system. Its wide range of torques also covers everything from small-diameter irrigation valves to large-diameter industrial process valves. Consequently, it is the most versatile automation solution in Cematic's catalog for On-Off 1/4 turn valves.
For the complete range of actuators, see electric actuator collection →