Modular construction is used extensively in this generation of electric actuators – the ELQ series. Plug in modules are used for a broad range of control options, these enable the basic actuator specification to be easily extended to that of fully-fledged control valve actuators.
Innovative design
The basic actuators' digital electronics enable communication with the newest fieldbus systems as well as the traditional 4 to 20 mA analog signals. Further product innovations include the addition of drive inserts for easy mounting to a wide variety of valve types and an exclusive universal power supply connection. Here most AC, DC and three phase supplies may be directly connected to the actuator. Thus the ELQ can rightly be regarded as the new generation of electric actuators.
Features include:
* Low power consumption: Saves power and cables, and therefore cost.
* 100% duty rating: Can be used for all applications, and protects against the motor overheating.
* 100% torque over the entire stroke: To cover all applications, even those valves with complex torque patterns.
* 3600 starts per hour: Can be used for all modulating applications.
* Constant engaged manual override: Safety (normally non-rotating) hand wheel is constantly available for manual emergency control.
* Compact, balanced design: Reduces cost for pipeline support, prevents stresses in the pipe work and eliminates side loads on the valve spindle.
Modular options
These are plug-in modules and can be pre-installed at the factory, at distributor level or even installed in the field, without special tools or any modification of the actuator. All these options may be installed on actuators with or without local control boxes:
* Speed control, with continuous and pulsating speed reduction.
* Local control box with soft-touch control knobs and protection class up to IP68.
* Position transmitter.
* Valve-positioner, with automatic initialisation and intelligent digital control.
* Additional switches.
Operating principle
The basic version of the ELQ is intended for simple open/close applications. For more sophisticated applications a large variety of options see to the additional requirements. These options (inserted modules) are easy to install on the motherboard without any special tools. The external control signals and the signals for the various insert modules are passed to the electrical motherboard via the terminal compartment, the 'serving hatch' of the actuator. The terminal block is also a plug-in item, so that when interchanging actuators the terminal block (complete with its wiring) may be reconnected to another ELQ.
The ELQ is provided with efficient, high-ratio reduction gear system. This provides the benefits of low power consumption, low noise emission and minimum backlash in the gear drive - achieved with a light and compact unit.
Options
Due to their modular construction, ELQ options can be easily installed. These options include:
* Extra limit switches.
* Position transmitter.
* Intelligent positioner.
* Status information module.
* Communication cards.
* Speed control.
* Local control unit.
Torque and sizing
The ELQ range comprises five different size types: ELQ100, ELQ200, ELQ300, ELQ500 and ELQ800. The choice of actuator depends primarily on the valves' torque requirement, but for optimum actuator sizing a number of factors need consideration. El-O-Matic has all the relevant technical data available - for practically all the quarter-turn valve manufacturers in the world. This electronic database enables the company to select the right actuator for any application, whether the valve is a ball, butterfly or plug variety.
Applications
For some applications electric actuators would be preferred over pneumatic actuators. One example would be where there are large distances between actuated valves, in this case electric cabling is often less expensive than installing a compressed air system. Electric actuators such as the ELQ with its many options may also be more suitable for applications requiring more complex communication between control room and actuator.
Compliances
The ELQ is produced in accordance with ISO 9001 standards. The actuator is also in compliance with the following industry standards:
* Water and dust proof IP67 (optionally IP68) to IEC 529 and NEMA 4 to ICS 6-110.15.
* Explosion proof EEx d llb T4 to EN50014/EN50018 and NEMA 7, 9 to ICS 6-110.24.
* Valve mounting is ISO 5211 and DIN 3337 compliant.
For more information contact El-O-Matic, 011 974 3336.
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