Types of Solenoids
Solenoids are available in two types based on the power used. They are
• AC powered Solenoid
• DC powered Solenoid
AC Solenoid versus DC Solenoid
• If there is a clearance between the moving and stationary iron cores of an AC solenoid, the solenoid coil will heat up and even the coil will burn out.
• In the case of a DC solenoid, its exciting current will remain constant regardless of the clearance of the moving and stationary iron cores. Therefore, a shock-absorbing material between dynamic and stationary iron cores can be provided for operation noise reduction.
• DC solenoids do not produce buzzing noises.
• AC solenoids produce buzzing noises as a result of the pulsating attraction force. A buzzing sound indicates that the plunger is not completely seated. If buzzing is permitted, the coil will overheat and eventually burn out.
• AC lead solenoid valves are relatively large in size. Use high amounts of power to create relatively slow operations.
• DC-operated solenoid valves produce rapid operation from compact devices with small, solid-state components.
• AC solenoid valves require a strong peak current to open the valve. Once the valve is open, the current drops to a level sufficient to hold the plunger to open the valve. This contributes to a reduction in overall power consumption.
• DC solenoid valves require a constant current for their operation, resulting in higher power consumption compared to AC solenoid valves.
• The service life of a DC solenoid is highly dependent on the amount of mechanical wear between the moving iron core and the guide (pipe). • The sliding part or section of the guide is considered specifically to extend its service life.
The Exciting Current
• The exciting current of an AC solenoid varies with the stroke, whereas the excitation current of a DC solenoid is determined solely by the coil DC resistance and remains constant regardless of the stroke. Regardless of plunger position, the heat generated by the coil winding’s resistance to current flow remains constant and weaker.
• The DC solenoid’s operating time is constant regardless of frequency. This is due to the fact that it is powered by DC.
• The AC solenoid’s operating time is not constant and varies with the frequency of operation, affecting heat build-up in the coil.
Desired Attraction Force
• With DC solenoid, it is possible to give the same gravitational force as the actual load by changing the shape of the mating section of the moving and stationary iron cores. `