China Hot selling Komat Su PC200-7 PC220-7 PC400-8 PC450-8 20y-979-6121 Air Compressor with high quality

Product Description

Product Description

We(HangZhou BST) export construction machinery parts, specializes in the manufacturing and supplying of Shantui, Cat and komat su parts for over 15 years.  Our company has a complete range such as  engine parts ,transmission parts,hydraulic parts,  electrical parts,drive parts,undercarriage parts, filter. Models such as komats D60/80/155,PC2-6420    Plunger     
6735-81-8031    TurboCharger
6732-11-3140    Nozzle 
20Y-30-07201    Roller Carrier
2A5-30-00111    Track Roller Assy:
20Y-27-77110    Sprocket
205-70-19570    Teeth
708-2L-5711    Block Cyl (R)
708-2L-33340    Retainer Shoe

komat su PC200-7 PC220-7 PC400-8 PC450-8 20y-979-6121 Air Compressor

Product Description
Part No.  20y-979-6121
Part Name

 air compressor

warranty 1 year
delivery time 3-5 days 
package wooden case
MOQ 1 piece
delivery way By express/Air/Sea,as your needs



Q1:You are a trader or manufacturer . 
      We are a trader .

Q2: How about the payment terms ?
We usually accept T/T . Other terms also could be negotiated .

Q3: Warranty 
      3-6 months warranty.  If any parts break during the warranty, Just offer us the proof . We’ll send you a new 1 !

Q5:If parts be lost during delivery , how solve ? 
      We’ll resend the parts free of charge . 

After-sales Service: 1 Year
Warranty: 1 Year
Type: Crawler
Application: Bulldozer & Excavator
Certification: ISO9001: 2000
Condition: New
US$ 50/Piece
1 Piece(Min.Order)

Request Sample

air compressor

How does variable speed drive technology improve air compressor efficiency?

Variable Speed Drive (VSD) technology improves air compressor efficiency by allowing the compressor to adjust its motor speed to match the compressed air demand. This technology offers several benefits that contribute to energy savings and enhanced overall system efficiency. Here’s how VSD technology improves air compressor efficiency:

1. Matching Air Demand:

Air compressors equipped with VSD technology can vary the motor speed to precisely match the required compressed air output. Traditional fixed-speed compressors operate at a constant speed regardless of the actual demand, leading to energy wastage during periods of lower air demand. VSD compressors, on the other hand, ramp up or down the motor speed to deliver the necessary amount of compressed air, ensuring optimal energy utilization.

2. Reduced Unloaded Running Time:

Fixed-speed compressors often run unloaded during periods of low demand, where they continue to consume energy without producing compressed air. VSD technology eliminates or significantly reduces this unloaded running time by adjusting the motor speed to closely follow the air demand. As a result, VSD compressors minimize energy wastage during idle periods, leading to improved efficiency.

3. Soft Starting:

Traditional fixed-speed compressors experience high inrush currents during startup, which can strain the electrical system and cause voltage dips. VSD compressors utilize soft starting capabilities, gradually ramping up the motor speed instead of instantly reaching full speed. This soft starting feature reduces mechanical and electrical stress, ensuring a smooth and controlled startup, and minimizing energy spikes.

4. Energy Savings at Partial Load:

In many applications, compressed air demand varies throughout the day or during different production cycles. VSD compressors excel in such scenarios by operating at lower speeds during periods of lower demand. Since power consumption is proportional to motor speed, running the compressor at reduced speeds significantly reduces energy consumption compared to fixed-speed compressors that operate at a constant speed regardless of the demand.

5. Elimination of On/Off Cycling:

Fixed-speed compressors often use on/off cycling to adjust the compressed air output. This cycling can result in frequent starts and stops, which consume more energy and cause mechanical wear. VSD compressors eliminate the need for on/off cycling by continuously adjusting the motor speed to meet the demand. By operating at a consistent speed within the required range, VSD compressors minimize energy losses associated with frequent cycling.

6. Enhanced System Control:

VSD compressors offer advanced control capabilities, allowing for precise monitoring and adjustment of the compressed air system. These systems can integrate with sensors and control algorithms to maintain optimal system pressure, minimize pressure fluctuations, and prevent excessive energy consumption. The ability to fine-tune the compressor’s output based on real-time demand contributes to improved overall system efficiency.

By utilizing variable speed drive technology, air compressors can achieve significant energy savings, reduce operational costs, and enhance their environmental sustainability by minimizing energy wastage and optimizing efficiency.

air compressor

Are there differences between single-stage and two-stage air compressors?

Yes, there are differences between single-stage and two-stage air compressors. Here’s an in-depth explanation of their distinctions:

Compression Stages:

The primary difference between single-stage and two-stage air compressors lies in the number of compression stages they have. A single-stage compressor has only one compression stage, while a two-stage compressor has two sequential compression stages.

Compression Process:

In a single-stage compressor, the entire compression process occurs in a single cylinder. The air is drawn into the cylinder, compressed in a single stroke, and then discharged. On the other hand, a two-stage compressor utilizes two cylinders or chambers. In the first stage, air is compressed to an intermediate pressure in the first cylinder. Then, the partially compressed air is sent to the second cylinder where it undergoes further compression to reach the desired final pressure.

Pressure Output:

The number of compression stages directly affects the pressure output of the air compressor. Single-stage compressors typically provide lower maximum pressure levels compared to two-stage compressors. Single-stage compressors are suitable for applications that require moderate to low air pressure, while two-stage compressors are capable of delivering higher pressures, making them suitable for demanding applications that require greater air pressure.


Two-stage compressors generally offer higher efficiency compared to single-stage compressors. The two-stage compression process allows for better heat dissipation between stages, reducing the chances of overheating and improving overall efficiency. Additionally, the two-stage design allows the compressor to achieve higher compression ratios while minimizing the work done by each stage, resulting in improved energy efficiency.


Intercooling is a feature specific to two-stage compressors. Intercoolers are heat exchangers placed between the first and second compression stages. They cool down the partially compressed air before it enters the second stage, reducing the temperature and improving compression efficiency. The intercooling process helps to minimize heat buildup and reduces the potential for moisture condensation within the compressor system.


The choice between a single-stage and two-stage compressor depends on the intended application. Single-stage compressors are commonly used for light-duty applications such as powering pneumatic tools, small-scale workshops, and DIY projects. Two-stage compressors are more suitable for heavy-duty applications that require higher pressures, such as industrial manufacturing, automotive service, and large-scale construction.

It is important to consider the specific requirements of the application, including required pressure levels, duty cycle, and anticipated air demand, when selecting between a single-stage and two-stage air compressor.

In summary, the main differences between single-stage and two-stage air compressors lie in the number of compression stages, pressure output, efficiency, intercooling capability, and application suitability.

air compressor

What is the difference between a piston and rotary screw compressor?

Piston compressors and rotary screw compressors are two common types of air compressors with distinct differences in their design and operation. Here’s a detailed explanation of the differences between these two compressor types:

1. Operating Principle:

  • Piston Compressors: Piston compressors, also known as reciprocating compressors, use one or more pistons driven by a crankshaft to compress air. The piston moves up and down within a cylinder, creating a vacuum during the intake stroke and compressing the air during the compression stroke.
  • Rotary Screw Compressors: Rotary screw compressors utilize two intermeshing screws (rotors) to compress air. As the male and female screws rotate, the air is trapped between them and gradually compressed as it moves along the screw threads.

2. Compression Method:

  • Piston Compressors: Piston compressors achieve compression through a positive displacement process. The air is drawn into the cylinder and compressed as the piston moves back and forth. The compression is intermittent, occurring in discrete cycles.
  • Rotary Screw Compressors: Rotary screw compressors also employ a positive displacement method. The compression is continuous as the rotating screws create a continuous flow of air and compress it gradually as it moves along the screw threads.

3. Efficiency:

  • Piston Compressors: Piston compressors are known for their high efficiency at lower flow rates and higher pressures. They are well-suited for applications that require intermittent or variable air demand.
  • Rotary Screw Compressors: Rotary screw compressors are highly efficient for continuous operation and are designed to handle higher flow rates. They are often used in applications with a constant or steady air demand.

4. Noise Level:

  • Piston Compressors: Piston compressors tend to generate more noise during operation due to the reciprocating motion of the pistons and valves.
  • Rotary Screw Compressors: Rotary screw compressors are generally quieter in operation compared to piston compressors. The smooth rotation of the screws contributes to reduced noise levels.

5. Maintenance:

  • Piston Compressors: Piston compressors typically require more frequent maintenance due to the higher number of moving parts, such as pistons, valves, and rings.
  • Rotary Screw Compressors: Rotary screw compressors have fewer moving parts, resulting in lower maintenance requirements. They often have longer service intervals and can operate continuously for extended periods without significant maintenance.

6. Size and Portability:

  • Piston Compressors: Piston compressors are available in both smaller portable models and larger stationary units. Portable piston compressors are commonly used in construction, automotive, and DIY applications.
  • Rotary Screw Compressors: Rotary screw compressors are typically larger and more suitable for stationary installations in industrial and commercial settings. They are less commonly used in portable applications.

These are some of the key differences between piston compressors and rotary screw compressors. The choice between the two depends on factors such as required flow rate, pressure, duty cycle, efficiency, noise level, maintenance needs, and specific application requirements.

China Hot selling Komat Su PC200-7 PC220-7 PC400-8 PC450-8 20y-979-6121 Air Compressor   with high qualityChina Hot selling Komat Su PC200-7 PC220-7 PC400-8 PC450-8 20y-979-6121 Air Compressor   with high quality
editor by CX 2023-10-03

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