As we all know, solenoid is widely used in our daily life like hydraulic mobiles, hydraulic valves, home appliances and office stationery, etc. A solenoid generally consists of solenoid coil, core tube and iron core.  Solenoid coil is a main component of solenoid. The solenoid is an actuator that transfers electrical energy into mechanical energy. How does a solenoid works? To be specific, when solenoid is powered, solenoid coil create electromagnetic force that is used to control machines. So that solenoid coil plays important role in solenoid, how to select solenoid coil? In fact, there is some common sense in solenoid coil selection, how much do you know about that?

Series and parallel connection of solenoid coil

Each coil has certain inductance value. Put two or more coils in series will increase inductance, total inductance equal to sum of each coil’s inductance. Formula for coil series connection: L= L1+L2+L3+L4……

Parallel connection of solenoid coil will decrease sum of each coil’s inductance. Formula for coil parallel connection: L=1/(1/L1+1/L2+1/L3+1/L4……).

Coil winding

In the processing of coil using, quantity of solenoid coil is nonstandard parts, which is wound by special requirement. There are some tips on coil winding.

  1. According to the requirement of circuit, select proper wound method. Besides that, you can decide wound methods based on inductance value, diameter of coil former and etc. The space-winding coil apply to high frequency circuit or UHF, when coil turns is less than 3~5, coil has better property without coil former, at the same time, Q value of coil up to 150~250, its stability is also great. Single layer close winding coil is suitable for short or medium frequency loop, coil’s Q value up to 150~250.
  2. Ensure ampacity and mechanical intensity of coil, choose proper conductor. It is inadvisable that use overground conductor to wind coil, which can avoid increasing resistance and decrease Q value. Meanwhile, overground conductor has small ampacity and mechanical intensity, and coil will be easy to burn or break.
  3. It is better to add an obvious mark on the coil tab, and installation or maintenance of coil will be more convenient.
  4. For different frequency of coil, choose various cores with different materials. Coil for audio band is generally made of silicon steel or Permalloy. Ferrite core is applied into low-frequency.

Methods for increasing Q value of coil

Q value is an important parameter for quality of coil. Improving Q value of coil is a key part for coil winding. How to increasing Q value of coil?

  1. Select coil conductor according to working frequency. For coil who works on the low low-frequency, it usually uses enameled wire or some conductors with insulation to wind. For coil who works on circuit under ten thousand hertz to 2MHz, it was wound by stranded insulation conductors.
  2. Select superior coil frame, and reduce dielectric loss. Compared to common materials, coil frame is made from high frequency dielectric material can reduce the dielectric loss. Ordinary high frequency dielectric material include high-frequency porcelain, Teflon, polystyrene, etc.
  3. Select reasonable size of coil can reduce losses. For a Single layer coil(φ20mm-30mm), when the ratio of its winding length and its outside diameter reach 0.7, loose of coil will be smallest. For a multilayer wound coil, the ratio of winding length and outside diameter reach 0.2-0.5, loose will be smallest.
  4. Select reasonable diameter of shield cover. Shield cover will increase loose of coil and decrease Q value.
  5. Using of iron core can reduce the coil turns. Add an iron core into solenoid coil not only decrease resistance value, but save the volume of coil.
  6. Select bigger diameter of coil. The single layer coil’ s diameter between 12mm to 30mm. Reasonable diameter of multilayer wound coil range from 6mm to 13mm. From the view of volume, the best range of coil diameter is 20mm-25mm.
  7. Reduce distributed capacitance of winding coil.

Using and installation of solenoid coil

All electronic components installation requires rational design and professional layout. For an installer, there are some tips on installation and using of coil.

  • Installation position of coil should accord with the design demands. Otherwise complete machine will be affected.
  • Before install coil, it is necessary for an appearance inspection. The inspection mainly focuses on soundness of coil structure, loose of coil turns, loose of lead contacts, rotation of core, and etc.
  • In the using of coil, trimming methods are considerable.
  • Maintain inductance value of original coil. During using of coil, for maintaining inductance value of coil, don’t change shape and sizes of coil, or distances among coils.
  • Adjustable coil should be installed at position that is easy to adjust, which is convenient for coil to achieve the best working condition.