Electric valve actuators can use AC (alternating current) or DC (direct current) motors, and for those buying the equipment for the first time in the company purchasing office, the choice of motors may seem irrelevant. However, the current that the motor receives does affect how well the actuator works and how long it lasts. Setting aside connection requirements for the moment, you have to look at how you're going to use the actuator and how continuously it will run in order to choose the right current.
Distance Likely Isn't a Factor
One of the reasons AC power became more popular than DC power was AC's ability to stay steady and provide adequate power all along the power line. With DC, power would fade the farther away you got from the generator. However, with actuators, this is not likely an issue because the actuator will be close to the machinery that needs the actuator's power. So do not worry if you see descriptions of AC working better with machinery far away. In an actuator's case, that's not a concern.
If the actuator will be in constant use, and you need a constant current instead of one that switches around, DC is better. Remember, alternating current has that name for a reason. A steady current is in DC's realm. That steady current allows for better timing and precision, so if the actuator has to run constantly and work machinery that has to be precise in its movements, DC will be better.
However, if the actuator needs to be in use for the long-term, as in not be replaced for a long time because of budget constraints, for example, AC would be better because the way DC motors are built, the parts inside can create a lot of friction. The operation isn't as smooth as you might find in AC motors. That can make DC motors fail earlier than AC motors.
Note that if the actuator is in an area with poor ventilation, an AC motor may be better as DC can create a lot of heat (mainly due to that friction). DC motors need good ventilation to cool down and to avoid fire risk.
Your choice of current will show in what is produced out of all that machinery. It's essential that you have a motor with the right current and power supply at all points for excellent production. For more information, contact companies like ETI Systems.