electromagnetismsolenoidsolenoid-valve
I have a 24VAC/60Hz solenoid. I used 12VDC just to try, and it worked good (well needless to say it worked as expected with 24VAC/60Hz).
What are the effects of a solenoid that's designed for AC running with DC? Applied force does not seem to be a problem in this case, so I think the main issue would be heat, as it is not running on the power source it was designed/optimized for. Technically speaking, what types of losses should be expected?
You should be aware that the datasheet linked is most likely not the correct one for the valve you will receive if you buy through that link. Various user comments and even the official description suggest this.
This is not the right type of valve for your application:
Note: This is not a gravity-feed solenoid. This means that you will need enough water pressure to fully open the valve. Check the datasheet below for exact details. It operates at a minimum of around 3 PSI
Your application (coffee maker) is most-likely gravity-fed. That means you have a tank of water and you let it out into your machinery for use driven solely by its own weight. With this valve, you will not be able to fully drain the tank. As the level gets lower, the pressure on the valve will decrease to the point that the valve won't open.
If you are using this valve you will need a pump on the tank-side of the system.
The detail of mechanical actuation and pressure systems is probably better handled on one of the mechanical engineering or physical sciences forums.
It's most likely a motorised valve.
Figure 1. Motorised valve attached to water hose line.
An industrial version of a motorised valve would have feedback potentiometer so that the actual position of the valve could be confirmed and, perhaps, proportional control could be achieved. Alternatively limit switches could be fitted to stop the motor once full travel had been reached.
In this case and in the case of the garden hose timers you linked I suspect that the motor would be run for a time and if the valve doesn't move then "too bad". With five or ten cycles per day the run time would only be half a minute or so and battery life should be good.
simulate this circuit – Schematic created using CircuitLab
Figure 2. Simplified representation of control circuit for open / close control including optional limit switches. With SW1 and SW4 closed as shown the motor would run CW until the CW limit switch opened.
Figure 2 shows how a simple DC motor would be switched by a 'H-bridge' to effect forward and reverse motion. SW1 to SW4 would, in a practical circuit, be replaced by transistors (with protection diodes).
Best Answer
It's ampere-turns that produce the magnetic field to attract the moving part of a solenoid and operating at AC means the inductance of the coil comes into play and there is a limiting impedance restricting current. At DC the solenoid dc resistance may be very low and to get it to work correctly might mean operating it at quite low dc voltages compared to the ac operating voltage.
If you try running it at 24V dc it could easily burn-out so be careful. The dc voltage should be chosen so that the current is approximately the same as the RMS ac current at 24V AC.