How to Choose Solenoids

In order to assist customers in choosing the right part, we provide materials blueprints and time-value charts that explain the correlation between stroke and Force.

Stroke and Force

The most important points when selecting a solenoid are stroke and Force. 
Stroke measures the degree of movement of the metal shaft in the device and how far it has separated from the main body. When it is pulled in to the closest point of contact with the body, this is measured as a starting point of 0. Distance away from this point indicates the stroke. As stroke increases, the Force of the device decreases. In other words, the further away the shaft moves from the body, the lower Force becomes.

As an example, consider a mechanism where moving a link is achieved by combining the solenoid with a spring part. When going from an OFF position (fig. 1) to an ON position (fig. 2), the stroke distance and the Force necessary to pull the shaft both change. This relationship is vital in choosing the correct solenoid.

* The solenoid’s temperature will increase as current is applied over time. As the temperature increases, the attractive power of the device will decline, so please select a device with enough of a buffer to cover your needs.

fig 1 off position
fig 2 on position

Time value

When measuring the same shape solenoid across different electric consumption levels, the Force of the solenoid will increase commensurately with more power consumption. The lower the resistance, the more the current will enlarge and the more power consumption can be expected to grow.

However, increased power raises the temperature of the solenoid; the more electrical consumption, the more rapidly it will heat up.

If the temperature rises to the point that it exceeds the solenoid’s insulation level, the resin parts or copper-wire coating may melt and short-circuit.

Before selecting a solenoid model, make sure to consider the expected usage (ON/OFF uptime and downtime) for your case.

If you cannot estimate your expected usage times or if you intend to keep the device running for long periods of time, please choose instead one of our “continuous use” parts.

relation chart of Foirce and stroke