I need to calculate the power needed to move a linear solenoid. I have a 12v linear solenoid. On the end of it is a small metal plate. 1/2" space, then a neodymium magnet in a fixed position. I want to actuate the solenoid away from the magnet. There is a 2.1lbs pull force between the plate and the magnet. I used a digital fishing scale, attached it to the rear of the solenoid, slowly pulled, and recorded the measurement when the magnetic force broke. What supply, or requirement for a supply, is need to actuate the solenoid? I can change solenoids also to meet the requirement for the supply. Please throw out some theories so I can test them. Thx.

 

You go to a supplier warehouse where you will see a data sheet that looks like this one. You need to know things like Voltage already given, Direction of Force, Stroke length, Duty Cycle, Rod Return Style, Rod Diameter, Force at Stroke Length, Frame Type and other information. Things like physical size and mounting configurations. Long list of variables need known when making a choice.

12 Volts so find a suitable force allowing at least 20% over what you need at least. These units are normally expressed in coil voltage and power expressed in watts. Dividing the voltage into the power will yield the current. So for example 12 volts @ 36 Watts would be 36/12 = 3 Amps so allowing overhead a 12 Volt 5 Amp power source is the minimum. Remember to pay attention to intermittent or continuous.

Ron

 

It's going to take a monster solenoid in that configuration, the solenoid force is always lowest when the plunger is extended- right where you need the most force.

I would re-think this concept.

 

It's going to take a monster solenoid in that configuration, the solenoid force is always lowest when the plunger is extended- right where you need the most force.

I would re-think this concept.

Yes, and notice in the example link I gave you the force is only mentioned at 50% of stroke. Keep the above in mind.

Ron

 

It's going to take a monster solenoid in that configuration, the solenoid force is always lowest when the plunger is extended- right where you need the most force.

I would re-think this concept.

I have about 2 inches of travel, it being the weakest at full extension. What if I get one with a longer reach and have it retracted part way already. When the power kicks on, it's already towards a stronger pull?

 

I have about 2 inches of travel, it being the weakest at full extension. What if I get one with a longer reach and have it retracted part way already. When the power kicks on, it's already towards a stronger pull?

Not going to help. This idea is like trying to get fast 0-60 times at the track with the parking brake on full the whole time.

 

How fast do does the plunger need to move?

 

What about going the other way? Let the spring do the work and then use the solenoid to reset everything.

 

Not real sure what this is being used for, so this might not be an idea you can use. But, what if instead of a pull in solenoid to get your movement you used another type of "solenoid". an electromagnet. With the electromagnet wired to give the opposite pole of the neo-manget, it would then repel when energized. Think of a loudspeaker without a cone, that is the principal they work on.

 

Thanks for all the advice guys, you have been super helpful in making me brainstorm. What ended up working is, Dell 12v 18A power adapter for a pc, a second 12v solenoid stacked on top of the other and wired together, and the solenoids set position so that the plungers are already about 1 inch in.