A pancake slip ring is one of the popular slip rings you will come across, especially in alternators, wind turbines and other mechanical and electric motors that have vertical length limitations. The pancake ring gets its name from the thin platter like design that offers very low vertical height and more horizontal length. There are various models and specifications for pancake slip rings, depending on the unique application and device. As such, it is essential to review your options carefully before making a decision. Here is a brief overview of the pancake slip ring, its specifications and how to find the right choice for your application.
Pancake slip ring specifications
Pancake slip rings are provided for various applications, so the design, volume, and diameter vary from one model to the next. However, there are general specifications for standard pancake slip ring as follows:
1. Electrical specifications
Pancake slip rings can carry 2 to 48 different circuits with a current rating of 5-20A per circuit. The voltage rating is 240/440 VAC/DC, with a dielectric strength below 500V at the 50HZ frequency. The electrical noise maximum is 10micro ohm with an insulation resistance of 1000M ohm.
2. Mechanical specifications
Pancake slip rings can come in inner diameter specifications ranging from 12.7mm – 80mm and thickness of 20mm to 91.9mm. The contact material features gold or other metal protected by an aluminum housing and can withstand temperature ranges between -30°C and +80°C. Pancake slip rings are also available in more than 18 typefaces designed for different applications.
How pancake slip rings work
Most pancake slip rings work in the same way as high voltage slip rings ad feature two main parts. The first is a stationary brush made of graphite using fiber brush technology, while the other is a rotating ring. The diameter and material used in the rotating component vary depending on the unique application requirements. However, these slip rings use the same underlying mechanism. The stationary metal graphite brushes convert electrical signals to the rotating component.
Pancake slip rings vs. other slip rings
Although most slip rings transfer electric signals and data from stationary parts to rotating components, pancake slip rings have unique design merits that isolate it in the group. There are several types of slip rings available, including through bore, PCB, miniature, fiber optics and USB slip rings, among others. Each model suits unique applications and you can also order custom slip rings for your device or application. The advantages and shortcomings of pancake slip rings are as follows.
- Special metallic brush and high vacuum technology augment rotating performance
- Low friction, electric noise and torque
- Can be used in fluid media to function as pneumatic or hydraulic slip rings
- Designed for applications with limited vertical space
- The design isn’t as strong as other high voltage slip rings
- Unsuitable for high-speed requirements
Uses of pancake slip rings
Although pancake slip rings offer the most efficient results when paired with silver, there are several other aspects to consider before ordering these electromechanical devices. Choosing a pancake slip ring is all about identifying reputable vendors and brands that provide slip rings specific to your machinery or application. Some of the applications that suit a pancake slip ring include:
1. Automobile showrooms
The flat design of pancake slip rings makes them ideal for low, medium speed, which suits automobile showrooms. The slip rings can accommodate the rotation of heavy mass and showroom vehicles tend to be displayed in circular paths and motions. Slip rings are behind the functioning of most automobile showrooms.
2. Offshore cranes
Offshore cranes may feature a combination of high voltage slip rings but always include a pancake design. They are useful in running components that have limited vertical space, especially those that involve full rotation.
3. Microwave ovens and motors
A microwave offers the most common use of pancake slip rings, which are responsible for the rotating disk inside the appliance. Pancake slip rings are available in different speeds and tracks, so you will find them in a wide variety of electric motors that run rotating components.
Choosing pancake slip rings and specifications
When purchasing new pancake slip rings, it is essential to outline all specifications before you start comparing existing options. There are several reputable brand names for pancake slip rings, such as Senring SNK series, Moflon MP 220 Series, JINPAT LPK Series and Rotarx and more. Here are a few insights to help you distinguish the ideal pancake slip ring for your needs:
- Use waterproof slip rings if your operation is outdoors to prevent rain damage and other weather elements.
- If you are using pancake slip rings in highly explosive operations such as mining, choose models customized for these harsh operating conditions. This is also important when the slip ring is installed on high heights.
- Pancake slip rings have varied RPM (rotation per minute), so you should choose according to equipment specifications. Some require high speed, while others work better with low RPM models.
- Choose freely definable cables. Although most models come with the standard 300mm rotor/stator cable, make sure it is freely definable and recommendable for your equipment.
- Purchase slip rigs from reputable vendors and brands. Although the demand for slip rings isn’t as high as other electromechanical devices, it is still essential to choose trustworthy vendors that have a growing reputation in the market.
Pancake slip rings are used in several electric motors and electromechanical systems that involve rotating parts. The slim design suits applications where there is more horizontal room than vertical space. Nonetheless, it is essential to determine if pancake slip rings are the ideal model for your machinery and application. Although there are various standard designs in the market, you will probably require custom designs. Fortunately, most vendors allow custom orders to ensure the slip ring is optimized for the unique operating environment. Pancake slip rings are application-specific and only used in devices that support them. As such, you should review your specifications carefully before ordering the slip ring to ensure it suits the operation.