We can get a large force from a small solenoid (by increasing the current) only if the application permits a very short solenoid "ON time" and a long "OFF time". This INTERMITTENT DUTY SOLENOID must be de-energized before it gets hot enough to burn up the coil. It cannot be contin- uously energized.	An AC solenoid should close in approximately 8 to 16 milliseconds. A solenoid energized at Point A should close at Point B, (about 8 milliseconds). When ener- gized at Point C, the sole- noid may not start until Point D, and finish until Point E, (about 8 milli- seconds).	As a solenoid is cycled faster, its temperature rises and its force decreases. Each time a solenoid is cycled (or closed), it re- ceives a high pulse of in- rush current which gene- rates heat in the coil. If these inrush pulses come fast enough...
...heat builds up faster than the solenoid can dissipate it. As the coil heats up, resistance increases, cur- rent flow and magnetism are reduced. The solenoid loses power and becomes too weak to close. The coil receives a continuous in- rush current, and it burns out.	99% of all U.S. power is 60 cycle frequency, and over 90% of all power outside the U.S. is either 50 or 60 cycle. A 60 cycle solenoid will over- heat when operated on 50 cycles, and a 50 cycle sole- noid will not produce rated force when operated on 60 cycles. Always use a coil designed for your specific power supply.	To summerize...a sole- noid is simply a special electromagnet. Magnetism produced by the coil cur- rent draws the plunger into the coil, reducing the high resistance air gap, and allowing the magnetism to flow 100% through low resistance iron.
We can make a solenoid pull by hooking onto the top of the plunger; or push from the bottom of the plunger.	Decco's copper shading coils keep a solenoid quiet by sup- plementing AC current fluc- tuations	Decco's insulated and lami- nated "C" stack and plunger reduce eddy currents and keep a solenoid cool.
Solenoid force increases as the plunger closes -- due to reduced air gap at the bottom of the plunger. Sole- noid force also increases with an increase in coil current.	When a solenoid is open, the inrush current is high, but drops as the solenoid closes.	And, finally -- the faster you cycle a solenoid, the hotter it gets. If cycled too fast, it will overheat and burn out.