How to Choose a Magnetic Latching Solenoid for Your Project
It is not just a matter of size or voltage when you choose a latching solenoid. You should make sure that it holds magnets in a way that is consistent with how you actually use it. You can use this simple engineering-based selection method for your product design or OEM projects.
1 Define motion and mechanical requirements
First, you should consider the basic laws of motion for actuators.
Essential factors:
Stroke length in mm: The stroke length is simply the distance that is moved.
Holding position: Is it a single position, extended, retracted, or dual position?
Type of load: Is it a push, pull, or rotate coupling?
Mounting space: What is the length, diameter, and screw holes?
Return type: Is it spring return or bistable magnetic return?
👉 Tip: Latching solenoids can be a powerful option when you need a bistable position but do not want to use power continuously.
⚙️ 2. Determine how much force is needed
You need to consider two forces in determining how much power is needed.
2.1 Force to Actuate
The force you need to move your load during switching. The forces include:
Force of friction
Force of spring
Force due to weight from outside or gravity
2,2 Force to Hold
The force you need to maintain your position when power is off. The forces include:
Resistance due to vibration
Safety factor, which is between 30% and 50%
Engineering rule: The required force must be more than or equal to load force, friction, and safety factor.
3 Determine the electrical parameters
The device is pulse-driven, which means it is a latching solenoid.
The parameters you should consider include:
Is it a latching solenoid?
Is it rated for a specific voltage, such as 5V, 12V, or 24V?
Is it driven with a specific duration, which is between 20-200 ms?
Resistance and current in a coil
Amount of power needed for switching
Driver circuit (H-bridge or reversing)
👉 Note: You’ll probably only need pulse energy, not continuous power.
4 Select type of latching structure
Some types are better suited for different uses:
Type Feature Common Application
Magnet that stays in placeSmart locks, IoT, and low power, small sizes
Two CoilsReliable switching and automation
Single Coil Reverse PulseSimple driver for Battery devices 🏭
5 . Think about the weather
The environment has a big impact on reliability.
Temperature range for operation
Duty cycle and switching frequency
Vibration or shock
Protection from humidity or IP
Resistance to corrosion, plated or material
6. Test for reliability and lifespan
Medical devices or production tools:
Rated life cycle – 100,000 to 1 million cycles
Control of residual magnetism
Sleeve and plunger wear
Noise level when used
7 Feature
The latching solenoid is commonly utilized in situations where a device is necessary to retain a position without the requirement for a continuous flow of electricity. This is because the solenoid holds its last position due to the use of permanent magnets or mechanical latching, making it perfect for situations where there is a need to save energy, reduce the use of heat, and use batteries, as you are bound to demonstrate in your content for Weilong.
8 Think about integration and customization
OEM customization is needed for several projects:
Design of mounting bracket
Wiring and connectors
Changing stroke length
Unique holding force
Special voltage for some coils
Feedback sensor – find correct position
✅ Quick Selection Checklist for Engineers
Stroke length needed: ____ mm
Force needed to switch: ____ N
Force of holding: ____ N
Voltage needed: ____ VDC
Time between pulses: ____ ms
Space limit: ____ mm
Temperature for operation: ____ °C
Life cycle goal: ____ cycles
