How does the duty cycle affect the performance and lifespan of a solenoid

When we started working on a solenoid project, customers have little knowledge of the application and related operation of solenoid and they don't know how the duty cycle of the solenoid will affects the performance of the device.  In fact, the product duty cycle plays a significant impact and interaction on the performance and life of a solenoid. As a professional solenoid man- ufacturers, we are glad to share our comment as below for reference:

Part  1 : Product Performance
1.1 Magnetic Force: The duty cycle affects the solenoid magnetic force. The longer of duty cycle, the strong current and power of solenoid is needed, in this way,  the unit  can allows  more                    current to flow through the solenoid coil to generate greater force. At the same time, a stronger magnetic field and magnetic force will be generated to drive plunger in linear movement.   
1.2 Response Time: The working duty cycle  affects the response time of the solenoid. Solenoids with higher duty cycles usually have faster response times, which allowing the magnetic field           to build up faster. This is critical in applications that require fast responding action,
1.3 Position Accuracy: In actual application, solenoids are used to control the position of components, and the duty cycle affects the accuracy of position control. A reasonable duty cycle can         adjust the corresponding magnetic force and push the plunger with high precision.

Part 2: Life cycles
2.1 Heating: Heating is one of the main factors affecting the lifespan of a solenoid.  80% to 100% of working duty cycle means that the solenoid is energized for a longer time, and the solenoid       coil  will generates more heating due to presentation of the working duty cycle. Overheating can cause insulation breakdown, reduced magnetism force , and increased wear on mechanical        parts. that  will  shorten the lifespan of the solenoid.
2.2 Wear: The duty cycle also affects the wear and tear of the solenoid. Every time the solenoid is energized and keep the plunger in moving, the friction of plunger is generated on the inside              components. The high presentation of the duty cycle is driving frequency in high rate, which increases the wear on the plunger, solenoid coil, and related mechanical parts. This can cause          the solenoid to degrade in performance and  eventually function failure.
2.3 Electrical stress: High presentation of duty cycle operation puts the solenoid under greater electrical stress. Repeated on-off cycles can cause arcing at the contacts, which can corrode the        contacts and  cause product failure. In addition, the high-frequency switching caused by long duty cycles can generate electromagnetic interference (EMI), while affecting the performance            and life of  other related electronic components and causing the performance of the solenoid itself to degrade.

Part 3: Relationship between duty cycle and power consumption
   The power consumption of a solenoid is related to the duty cycle. The current and the corresponding resistance value through the solenoid coil will be larger, and the duty cycle needs to be         longer also. the higher of the power consumption will be increasing accordingly. According to this formula, the average power consumption of the solenoid will also increase proportionally.        For example, assuming that the current and resistance remain unchanged, if the duty cycle is doubled, the average power consumption used will also double.

Part 4: Current and heating:

  The longer of the duty cycle, the greater of the current will go through the solenoid and heating of temperature rising will be in high condition accordingly. This is why solenoids will be hotter. If the duty cycle is too long, the solenoid will be in overheat, which will not only increase the power consumption, but also damage the solenoid and its surrounding components. On the other hand, a lower of duty cycle reduces the solenoid consumption, which keep the current and the temperature in reasoan condition.  

Part 5: How to Calculate Solenoid Duty Cycle
Solenoid duty cycle is expressed as a percentage, representing the proportion of time that  the solenoid is energized. Here is a detailed breakdown of the calculation process:

Duty Cycle = Off Time / (On Time + Off Time) x 100 (D = Ton / Toff ​×100%)
If the energized time is continuous, the solenoid needs to be rated for 100%. However, if the solenoid is energized for 15 seconds, then de-energized for 45 seconds, and then energized again, the total switching period is 60 seconds. This represents a 25% duty cycle. the sample calculation as below: 

For example: 120 seconds on + 120 seconds off 
120/(120+120)×100
120/240 x 100 = 50%  , the working duty cylce is 50%.

60% is: 120 seconds
Off time = T
60 = 100 x 120/(120 + T)

The rated of duty cycle is usually based on operation at a standard ambient temperature of 35°C and a specific DC 6--24V voltage . Most of our solenoids ( our product ranges included the push pull solenoid, open frame type solenoid, tubular solenoid , latching solenoid , automotive solenoid, rotary solenoid, solenoid valve and electromagnet ) can provide the standard duty cycles from 10% to 100%, suitable for application in a variety  projects application.

Part 6 ：  Does the duty cycle of a solenoid be adjusted?

Yes, the duty cycle of a solenoid can be adjusted. Here are some common ways as below:

6.1 Adjusting the frequency:  In some cases, changing the frequency can adjust the duty cycle. However, this method is not as simple as using a PWM controller. When changing the          frequency, the time of each cycle will also change; if the on time is kept relatively constant, the duty cycle will be affected accordingly.
6.2 Using a variable resistor or adjust the power current: In simple circuits, a variable resistor or inceasing the current can be adjusted force as well as the working duty cycles. By changing the value of the resistor, the power current across the solenoid will be changing the force as well as  the duty cycle accordingly.  

Part 7: Practical Application
Measurement: In product applications, one should measures the starting force and shutdown times  that require specialized equipment such as an oscilloscope. An oscilloscope can display the electrical waveform of the signal controlling the solenoid, allowing accurate measurement of the time interval distance. If the temperature rise is too high, it can be adjust the current and the duty cycle accordingly.
Adjustable Duty Cycle: In some cases, the duty cycle of a solenoid may change through the long operation time. To calculate the duty cycle, you need to measure the corresponding duty cycle at the specific point in time that determines the duty cycle.

Part 8: Conclusion:
Finally, the solenoid duty cycle is a critical point that affects the performance and lifespan of a solenoid. It determines the average magnetic force, responding time, and positioning accuracy of the solenoid, which is essential for the proper design of various applications such as automotive systems, industrial machinery and circuits. However, it also directly affects the life of the solenoid through heat, mechanical wear and electrical stress. Therefore, careful consideration and optimization of the solenoid duty cycle is essential to achieve the best performance and ensure the life and reliability of the solenoid in different applications.  If  you have any question about the working duty cycles , pls contact us through email : info@drsoenoid.com