Dc Slip Ring

DC Slip Ring is a Rotating Electrical Connection device designed specifically for DC power supply and signal transmission. Its core function is to achieve stable power and signal transmission between rotating and fixed components through physical contact between brushes and conductive rings. Compared to AC Slip Rings, DC Slip Rings have significant advantages in low-frequency signal transmission, high current carrying, and high reliability demand scenarios, and are widely used in industrial automation, medical equipment, aerospace, and new energy fields.

Technical Characteristics

Low contact resistance and high conductivity

DC slip rings use precious metals (such as gold and silver) or copper alloys as conductive materials, and their contact resistance can be stably controlled at ≤ 5m Ω (the industry average is ≤ 50m Ω), ensuring a temperature rise of ≤ 35 ℃ when transmitting high currents (such as 100A/60V). For example, a certain model of DC slip ring has a contact resistance fluctuation range of less than 0.2m Ω and a lifespan of over 120 million revolutions when transmitting 50A current. In addition, its dynamic contact resistance stability (≤ 0.005 Ω) is improved by 99.9% compared to traditional carbon brush slip rings (fluctuation range>5m Ω), significantly reducing power loss and heating risks.

High speed and low-noise design

The DC slip ring supports a maximum speed of 18000 revolutions per minute (traditional slip rings usually have 8000 revolutions per minute), and the contact pressure between the electric brush and the conductive ring is precisely tuned (1.5-2.5N). Combined with self-lubricating materials, the operating noise is ≤ 45dB (A), which is about 70% lower than that of carbon brush slip rings. In the application of industrial robot joints, a certain type of slip ring can stably transmit 24V/20A DC power at 15000 revolutions per minute, with noise levels in compliance with ISO 15665 standard, and can maintain stable performance even at extreme temperatures ranging from -40 ℃ to+100 ℃.

Anti electromagnetic interference and signal stability

The DC slip ring significantly reduces the temperature drift effect of contact resistance (<0.01m Ω/℃) by optimizing the brush material and conductive ring structure, ensuring the stability of signal transmission in high-temperature environments. In medical CT equipment, a certain type of slip ring can simultaneously transmit 48V/10A DC power and 1080P@60Hz High definition video signal, and under strong electromagnetic interference environment (such as 100V/m electromagnetic field strength), the signal error rate is less than 10 ⁻¹ ². In addition, its insulation resistance is greater than 10 ¹⁴ Ω, and its dielectric strength is greater than 5kV (DC), effectively shielding external interference.

Application scenarios and industry value

Medical equipment field

In spiral CT equipment, the DC slip ring needs to support continuous rotation of the X-ray tube at a rate of 3-5 revolutions per second, while transmitting high-power (30kW) and high-definition video signals. A certain type of slip ring has achieved optical fiber assisted transmission technology 4K@60fps The lossless transmission of medical images can maintain stable performance even at extreme temperatures ranging from -40 ℃ to+85 ℃. According to market research, the global market size of medical imaging equipment slip rings is expected to grow from 180 million yuan in 2023 to 280 million yuan in 2030. DC slip rings occupy over 45% of the high-end market share due to their high reliability and low maintenance costs.

Industrial Automation and New Energy

In industrial robot joints, DC slip rings can synchronously transmit power (24V/20A) and real-time control signals (such as CAN bus) with a response delay of less than 0.5ms. In wind power pitch systems, a certain type of slip ring supports power transmission (60V/100A) and synchronous transmission of SCADA monitoring data, with an anti vibration kinetic energy of 12g (acceleration), meeting the IEC 61400-1 standard. In addition, the modular design of the slip ring supports quick replacement of conductive rings and brushes, reducing maintenance time by 80% compared to traditional solutions.

Aerospace and Military Industry

In satellite communication antennas, DC slip rings need to withstand high radiation (total dose>100krad) and extreme temperature differences (-180 ℃ to+120 ℃) in the space environment, and their fiber transmission loss is less than 0.2dB/km in the C-band (4-8GHz). In military radar systems, a certain type of slip ring supports 360 ° unrestricted rotation of phased array antennas, with a transmission power density of 60W/cm ², while controlling the signal phase error to<0.05 ° to ensure radar detection accuracy.

Maintenance and upkeep guide

Daily cleaning and testing

Use a dust-free cloth dipped in isopropanol (concentration ≥ 99.5%) to clean the surface of the conductive ring and electric brush, avoiding the use of cleaning agents containing grease. Use a contact resistance tester (such as Fluke 1508) every quarter to test the performance of the slip ring. The normal contact resistance should be ≤ 5m Ω. If there is abnormal noise (>50dB) or temperature rise (>40 ℃), the machine should be stopped immediately for inspection.

Replacement of electric brush and conductive ring

When the electric brush wears down to one-third of its original length, it needs to be replaced. When the surface wear depth of the conductive ring is greater than 0.1mm, it needs to be repaired or replaced. When replacing, it is necessary to ensure that the contact pressure (1.5-2.5N) between the new electric brush and the conductive ring matches the material (such as gold to gold, silver to silver), to avoid signal interruption caused by poor contact. In addition, it is necessary to regularly check the tension of the brush spring (standard value 1.8-2.2N) to ensure contact stability.

Lubrication and Sealing Management

Apply high-temperature grease (such as Mobil SHC 634) to the bearing area every 5000 hours, with a dosage controlled at 0.1-0.2g/bearing. In humid environments (relative humidity>80%), desiccants (such as silicone particles) should be replaced every 6 months, and sealing rings (such as O-rings) should be checked for aging or damage. For slip rings designed with lubrication free bearings, the bearing clearance should be checked every 2 years (standard value 0.01-0.03mm).

Life management and fault diagnosis

Develop a replacement plan based on the cumulative number of rotations (recommended ≤ 90 million rotations) or time (recommended ≤ 7 years). In extreme working conditions such as high speed and high temperature, the maintenance cycle needs to be shortened to 45 million revolutions per minute or 4 years. When diagnosing faults, the signal waveform can be detected through an oscilloscope (normal waveform should have no distortion or attenuation), or the surface temperature can be monitored using an infrared thermometer (normal temperature rise ≤ 35 ℃). If arc erosion marks are found on the surface of the electric brush, the electric brush should be replaced immediately and the surface smoothness of the conductive ring should be checked (Ra ≤ 0.4 μ m).