Motors regularly used to complement electric linear actuators are, in most cases, classic direct current motors of 12V and 24V. However, there are cases when other types of electric motors and other Voltage can be used – 48V, 60V, 90V, 190V. To change the direction of movement of the direct current linear actuator rod it is necessary to change its motor rotation direction. In case of using a collector DC motor, it is enough to reverse the polarity of the energy supply – simply swap two wires supplying the energy to the motor. Usually, the functionality of such motors is based on using an automatic switch that reverses the polarity of the power supply.
To sum the above-mentioned, DC linear actuator is the one that works using the energy supplied by the direct current electric motor. Here are some of the most known linear motion mechanisms: mechanical jackscrews, conical reduction drives, worm gearboxes, cylindrical gears and so on.
The Reverse Polarity Principle
There are 2 terminals in the terminal box. When the polarity is changed, the motor changes the direction of rotation. The extremely important feature of changing the rotation direction is the full motor stop. This helps to avoid possible damage to the engine as reverse movement causes great pressure on the electric motor. Furthermore, the rotation speed can be adjusted using the controllers. In the case of the direct current motors – they can surely be used while overloaded. Nevertheless, when this technology is implemented in areas where high ambient temperatures are frequently causing the malfunction of the complex mechanisms, power limitations become extremely important as preventive measures taken to avoid overheating. Quite a valuable moment to remember is that the engine torque should be reduced also as the rotational speed is capable to cause overheating as well.
Talking in a simple manner, DC motors are supplied with energy and controlled via 2 energy wires. If there is need to change the direction of motor rotation, swapping the wires either at anchor or at the electromagnetic coil is required. This functionality can be provided by a variety of switching devices available at the engineering market. However, in the case of remote control of motors and changing the polarity of the energy supplied, the polarity for both the anchor and the stator will change. As a result, the engine will not change its direction of rotation. Nevertheless, there are commutators capable to be adjusted to change the polarity either for the anchor or for the stator.
DC Linear Actuators Benefits
- These engines can be used in enclosed spaces without moisture. The operating mode of these engines can reach 100 percent, accordingly, not all of the models are capable of such extreme-level productivity;
- Self-lubrication of the linear actuators are possible in cases when their direct current motors are equipped with a nut;
- Less repair work needed when comparing to hydraulic linear actuators;
- Total controllability allowing numerous feedback options, programmability along with fixed limit switches during critical machine operations;
- Positioning performance and compact dimensions contributing to higher energy efficiency;
- Reduced downtime thanks to improved component life in addition to manual override redundancy.
In many cases, direct current electric linear actuators are more suitable than the alternative current once as their manual control, the increased duty cycle, and the changeable polarity provide the variety of possible adjustments needed for different situations like increased humidity and extremely high temperatures. The best direct current linear actuator for a particular operation is always the one that was picked up accordingly with the specifications needed. Therefore all the preconditions should be well-counted before choosing the actuator potentially capable to cope with the upcoming workloads.