Shindengen Open Frame DC Solenoids Technical Guide

Visit our webpage for Shindengen Open Frame DC Solenoids to view all available models and for access to datasheets.

Design & Features

The open frame solenoid is the simplest form of con­struction of all the types of solenoids manufactured (see Fig. 1). Though the design is simple in construction, obtaining maximum performance requires the use of high permeable steel, and good quality manufacturing technology to assure the minimizing of air gaps in the metal frame assembly. Additionally, high quality coil winding techniques are used to maximize the number of coil windings that are housed in the allowable space.

Stroke and force

The open frame solenoid is designed for long strokes. As such, the pole piece designs are conical to maximize performance over longer strokes. To improve efficiency, the solenoid stroke should be minimized in the appli­cation.

Figure 1

Operation Considerations

A. Temperature
Coil data for the open frame solenoids shows the values at ambient temperature 20°C and with a stan­dard heat sink. If a solenoid is used at a rating shown in the coil data, it is designed so that the coil temperature rises and reaches equilibrium at approximately 65°C. In applications where the ambient temperature is higher than 40°C, possible thermal damage can occur. Temperature rise tests should be performed by the user to assure that the coil does not reach 105°C. Custom models can be constructed to operate at temperatures higher than 105°C without thermal damage.

B.  Return Spring
The open frame solenoid does not include a return spring. Therefore, the application must include a return spring.

C. Plunger & Shaft Modification
It is not recommended for the user to modify the plunger or shaft, as the shafts are manufactured and plated at the factory. Custom configurations can be considered by the Shindengen factory.

D. Solenoid Installation
The open frame solenoid uses tapped holes for mount­ing in the frame. Caution needs to be observed that the mounting screws used to attach these solenoids are the correct length so as not to damage the coil.

General Characteristics

Insulation class:Class E (120°C), Lead wire class A (105°C)
Dielectric strength:AC 1000V 50/60 Hz 1 min. (at normal temp. and normal humidity)
Insulation resistance:More than 100 Mohm at DC 500V megger (at normal temp. and normal humidity)
Expected life:300,000 cycles

Note: Solenoid cycle life is very dependent upon side load, frequency of use and environmental conditions. Cycle life tests should be performed by the user.

How to select a solenoid

Before selecting an open-frame solenoid, the following information must be determined:

A. Force
The actual force required in the application should be increased using a safety factor multiplier of 1.5 to arrive at the force value that should be used in your specification.

B.  Duty Cycle
Use the following formula to calculate duty cycle. Also note the maximum on time.
                                        On Time     
Duty Cycle (%) =   On Time + Off Time   x  100

C.  Stroke
Stroke is determined by application requirements.

D.  Operating Voltage
Operating DC voltage is determined by the application and voltage available.

After determining these specifications, the correct solenoid can be selected for the application using force-stroke characteristic tables and graphs. The coil data is also provided on our datasheet for different sizes of magnet wire.

To determine the force output of the solenoid after temperature rise, please use the amp-turn force graphs (located at the end of this guide) after calculating the amp-turns.

Ordering Information

When ordering an open frame solenoid, use the part numbers provided in the datasheet.
Example of a complete part number: SK0520A06AA


For open frame solenoids without modifications the following part number system is used on product labels. Example part number: SK0520A06AA 9405
SK0520A06AA 9405
Part Number Date Code (year and week)
Note:  A custom solenoid (any modification to a standard design) requires the assignment of a special part number which will identify the custom model and date code.
Performance Charts

Use the links below to access performance charts for Small Push-Pull Solenoids.

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