Shindengen Small Push-Pull DC Solenoids Technical Guide
Small push-pull solenoids have the same features as the conventional push-pull solenoid. The push-pull solenoid design uses a coil with the maximum amount of magnet wire in the smallest amount of space. This coil assembly is then packaged in a metal housing using highly permeable steel to obtain the maximum force in the minimum size and weight.
This small push-pull solenoid size is a very cost-effective solution when small movements are required and/or available electrical power is limited.
Stroke and Force
The conical pole piece configuration is the standard design for the small push-pull solenoid. For the best performance efficiency, the stroke should be kept to a minimum.
Coil data for small push-pull solenoids shows the values at ambient temperature 20°C and without the use of a heat sink. If a solenoid is used as rated in the coil data, it is designed so that the coil temperature rises and reaches equilibrium at approximately 85°C. Possible thermal damage can occur in applications where the ambient temperature is higher than 20°C. Temperature rise tests should be performed by the user to assure the coil does not reach 120°C. Custom coils can be constructed to operate at temperatures higher than 120°C without thermal damage.
B. Air Gap Spacer
The small push-pull solenoid uses an air gap spacer between the armature and the case. This spacer is installed to prevent the armature and base from mechanical contact with each other, which would cause residual magnetism.
C. Return Spring
The small push-pull solenoid does not include a return spring. Therefore, the application must include a return spring.
D. Shaft Modification
It is not recommended that the user modify the shaft, as shafts are fabricated before assembly. Special shaft configurations are considered upon request.
E. Solenoid Installation
The small push-pull solenoid uses tapped holes for mounting in the base. 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.
|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:||Standard life: 5 million 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 a push-pull solenoid, the following information must be determined:
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.
Duty Cycle (%) = On Time + Off Time x 100
Stroke is determined by application requirements.
D. Operating Voltage
Operating DC voltage is determined by the application and voltage available.
After determining the specifications listed above, the correct solenoid for the application can be selected using the torque characteristics tables. Coil data is also provided in tables that use American Wire Gauge (AWG) for magnet wire. If the exact operating voltage is not in the coil data table use the nearest voltage shown in the table.
To determine the force output of the solenoid after temperature rise, please use the amp-turn force graphs at the end of this guide after calculating the amp-turns.
When ordering a small push-pull solenoid, the correct part number needs to be determined, from the following combination of characteristics (1-5):
- M – Metric Thread
F – SAE Thread
- Solenoid Size (example – 144C)
- Coil Voltage from datasheet tables (at 100% duty cycle)
Example of a complete part number:
The part number above distinguishes a SmallPush-Pull solenoid with  Metric Threads;  size 144C;  6V coil.
For small push-pull solenoids (no modifications) the solenoid label will include the part number and date code. The date code identifies the year and week of manufacture.
Example part number: M 144C-6V 9401
Coil Voltage at
(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.
Use the links below to access performance charts for Small Push-Pull Solenoids.
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