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PROPORTIONAL SOLENOID AND WET TYPE (On-Oﬀ) SOLENOID
1. Design and Features-Proportional Solenoids

The conventional solenoid is a digital device, meaning
the plunger is either in the energized or de-energized
position. Proportional solenoids, however are an analog
device, allowing for incremental positioning. This feature is made possible by a unique design of the magnetic
supplied in your application. Thus the position of thearmature is controlled by varying the input current tothe coil. The more current that is applied to the coil,the further the armature moves in its stroke (toward
the pole piece). Our proportional solenoids provide
stable output force characteristics with low hysteresis
and a fast response time for a wide variety of applications, especially for hydraulic applications. (Fig. 1)

At these intersections the forces are balanced (the solenoid's output force is equal to the spring load). Thismeans that with a coil current of ²i, a balancing force by
the spring against the plunger is equalized with theresulting position of S². When varying the coil current toi², the plunger moves to a new “balancing” position ¹S.
By varying the coil current, the plunger positioning canbe controlled and moved “proportionally” to diﬀerent
positions by controlling the coil current. However, inactual applications, consideration has to be given to theinﬂuences of load variation, hysteresis and temperature.

Fig. 2

Fig. 1A) Relationship Between Stroke and Force
A proportional solenoid has two ranges of stroke : thecontrol stroke where the plunger position is dependent
on the applied current, and the approach stroke whereforce is dependent on stroke position. The stroke istions use only the control stroke. Fig. 2 shows the characteristics of stroke and force. The spring characteristics is the spring load that has been installed outside thesolenoid.
Positions S¹ , S ², and 0 are where the force curves ofeach current : i¹ , i ², and i³ intersect the spring characteristics.

98B) Hysteresis
Hysteresis is represented as a ratio (%) of the rated
output force when measured at the same position, as
the plunger approaches that position from two directions. In an ideal world, there is no friction, and noresidual magnetism, but in the real world these factors
do exist and they do aﬀect performance. As such theforce when measured at the same position will be diﬀerent
when that position is approached from two directions.
This force diﬀerence expressed as a percentage iscalled hysteresis. This can be seen in the following
formula :Hysteresis (%)= ∆X
X

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PROPORTIONAL SOLENOID AND WET TYPE (On-Oﬀ) SOLENOID
3. Ordering Information

When placing an order for either proportional solenoids or on-oﬀ solenoids, when doing design work,
please contact our agents for technical support.

Fig. 3

2. Design and Features-On-Oﬀ Solenoids

On-Oﬀ solenoids are designed for use in directional
ciency, solid mechanical structure and steady force
characteristics, all in one package.

Proportional Solenoids and Wet ON-OFF Solenoids

Fig. 4

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PROPORTIONAL SOLENOID AND WET TYPE (On-Oﬀ) SOLENOID
The following are examples of standard solenoids

PS30C

PS36C

PS50C

SW3012C

SW3813C

SW4417C

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