Electrical Slip Ring Technology Research – Contact Resistance
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Slip ring technology is widely used in celestial navigation, optical tracking, optical measurement, optical search devices and automated machinery. In this article, experimental and engineering analysis of contact resistance and insulation properties of the electrical slip ring.
1. The contact resistance of the slip ring
If the contact resistance of the conductive slip ring is large, the current through the contact point relative temperature will be high, may even cause the wire brush and slip ring welding, while the contact pressure increases, these will affect the information transfer effect, and therefore the better the smaller of contact resistance. Factors that affect the size of the contact resistance include: a contact portion of the material, the form of the contact surface and the contact pressure.
Select the contact portions of the material
Slip ring made of a conductive ring and wire brush the two main parts. Its main properties are: high conductivity, good thermal conductivity, high melting point, small resistance temperature coefficient (has antioxidant, anti-sulfide, anti-corrosive gases and other characteristics); has a certain hardness, wear resistance and other characteristics. After testing, the choice of brass conductive ring better, you can use gold wire brush nickel wire, nickel gold wire but is expensive, generally used in beryllium (QBe2), in addition, can also choose brass plated layer of palladium on the surface meet good electrical properties, have a good anti-corrosion effect.
Contact style of wire brush and slip ring
Contact style of point contact and surface contact, general slip rings are point-contact. Contact resistance of point contact is small, because the contact area is small, small current through, after several tests, the maximum current is not more than 10 amps, if the slip ring to transfer current of more than 10 amps, you should consider taking surface contact type. Surface contact type require relatively large radial dimension, the structure is more complex, the location must have enough space to be used.
Wire brush pressure on the slip ring
Wire brush pressure for slip ring directly affects the size of the contact resistance, the greater the pressure the smaller the contact resistance, however, increasing the pressure of a certain limit, if it exceeds the limit will increase the friction torque, the contact part of the wear large. Determine the size of this pressure is very important that this pressure to make a good wire brush pressure in the slip ring, but does not affect the rotation of the slip ring. Experimental results show that the pressure in the 12 ~ l5 grams more appropriate, after several tests, the minimum contact resistance of slip ring can be done to 0.03 ~ 0.05Ω.
2. Insulation properties of slip ring
Slip ring is better insulation, the insulation resistance between the ring is greater than 100MΩ, breakdown voltage 1000V without breakdown. Slip ring made up of many conductive rings, 1.5mm minimum distance between the rings is appropriate, it depends on machined 1.5mm slot, but the main thing is to ensure dielectric strength that after potting. Radial size of the conductive slip ring is large, easy glue, small size is difficult, now we can make an outside diameter of 12.7mm mini slip ring. Slip ring of dielectric strength depends mainly on potting process and insulation material.
ARS design and manufacture slip rings for a wide range of industry applications. Ars’s products provide reliable transfer of signal, power, fluid and gas from stationary to a rotating structure.
More details please visit http://www.arslipring.com/
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