A given solenoid size can dissipate a certain amount of heat. So depending on the input voltage you can operate it at varying duty cycles on a given solenoid.
Take a look at
this solenoid's data sheet.
It is rated at 10w continuous duty in all it's configurations. The size of the wire used for the coil determines the voltage vs duty cycle.
Look at the first line using awg 23 wire which gives the coil a resistance of 1.52 ohms.
If you operate it at 3.9 volts it is rated at 10w with a 100% duty cycle.
Operate it at 12.3 volts and it will be rated at 100w and a 10 % duty cycle.
Order it with a 4.01 ohm, 25 awg coil and you can operate at 12.7v with a 25% duty cycle.
Be sure to note the heat sink requirements for the listed ratings.
Why do things the easy way when you can do it with a robot? - MissInformation [more] 
Hybrid Mode
