Hydraulic motor-AC generator coupling

• Vardges
In summary, the conversation discussed the possibility of using a hydraulic motor and AC generator to produce high efficiency electric energy. It was determined that the efficiency would not be very high due to losses in the conversion process. The conversation then shifted to the idea of using a hydraulic press mechanism to drive a reciprocating pump and couple it to a 100 KW PM generator, but this idea was deemed impossible due to the laws of thermodynamics.
Vardges
Hi there. I have an idea which is interesting. Let's suppose, we have AC generator which has capability of 100 KW and 100 RPM. And we have hydraulic motor which produces 500 RPM and 2400 Nm torque. Additionally, I attach 5:1 gearbox for reducing 500 RPM to 100 RPM for Ac generator. Please, share your thoughts, is it possible to produce high efficiency and electric energy with this combination?

Die Energie der Welt ist konstant (Clausius)

Vardges said:
Hi there. I have an idea which is interesting. Let's suppose, we have AC generator which has capability of 100 KW and 100 RPM. And we have hydraulic motor which produces 500 RPM and 2400 Nm torque. Additionally, I attach 5:1 gearbox for reducing 500 RPM to 100 RPM for Ac generator. Please, share your thoughts, is it possible to produce high efficiency and electric energy with this combination?
Welcome to PF!

Depends -- what is making the hydraulic motor spin? And what do you consider "high efficiency"?

The hydraulic motor will need a power of at least 125 kW. Where is the point?

Last edited:
Vardges said:
Hi there. I have an idea which is interesting. Let's suppose, we have AC generator which has capability of 100 KW and 100 RPM. And we have hydraulic motor which produces 500 RPM and 2400 Nm torque. Additionally, I attach 5:1 gearbox for reducing 500 RPM to 100 RPM for Ac generator. Please, share your thoughts, is it possible to produce high efficiency and electric energy with this combination?
125kW input for 100 kW output is not generally considered high efficiency. In practice it would be even less than that.

russ_watters said:
Welcome to PF!

Depends -- what is making the hydraulic motor spin? And what do you consider "high efficiency"?
The hydraulic motor is spun by hydraulic pump. And the hydraulic pump is powered by electric motor.

Here is the clarification of what I want to get. I want to use hydraulic mechanism to get electric power. Hydraulic mechanism can be cylinder or hydraulic motor.

Dale said:
125kW input for 100 kW output is not generally considered high efficiency. In practice it would be even less than that.

Hydraulic motors have 10 times more power density than electric motors have. I want to get mechanical advantages from hydraulic motor torque to generate electric power. That's all.

You cannot generate electric power from nowhere. You need a power source: A generator driven by hot gas, water, wind, ..., light shining on solar cells, or something else.

Converting energy from one type to another is always associated with losses. Electricity -> mechanical motion -> electricity means you get strictly less electricity out than you get in. It does not matter which type of motor and conversion you use.

russ_watters
Vardges said:
Hydraulic motors have 10 times more power density than electric motors have.
Power density is not relevant to the question of efficiency. For efficiency all that is considered is the input power and the output power. It doesn't matter how dense the power is, just how much goes in and how much comes out.

Based on your numbers above at least 125 kW hydraulic power goes in and at most 100 kW of electric power comes out. That is not a very high efficiency, but might be acceptable in some scenarios (e.g. If the hydraulic power were very inexpensive so you could sell the smaller amount of electrical power for more)

Vardges said:
I want to use hydraulic mechanism to get electric power
Sure. That is what a hydroelectric power plant does. As @mfb and I have said, the efficiency of such a conversion is strictly less than 1.

Last edited:
russ_watters
Dale said:
Power density is not relevant to the question of efficiency. For efficiency all that is considered is the input power and the output power. It doesn't matter how dense the power is, just how much goes in and how much comes out.

Based on your numbers above at least 125 kW hydraulic power goes in and at most 100 kW of electric power comes out. That is not a very high efficiency, but might be acceptable in some scenarios (e.g. If the hydraulic power were very inexpensive so you could sell the smaller amount of electrical power for more)

Sure. That is what a hydroelectric power plant does. As @mfb and I have said, the efficiency of such a conversion is strictly less than 1.

Guys, here is the point. A typical hydraulic press consumes 5-7 KW electricity to obtain 50 ton (500 kilo Newton) capacity for pushing/pulling. Its hydraulic rod travel is 2in/sec. Let's suppose, if I use that rod in a reciprocating pump, I will get a very high torque, especially if the AC PM generator is has a very low RPM (50 RPM is available in the market!). I want to use hydraulic press mechanism in reciprocating pump and couple them to 100 KW PM generator. That's it.

Vardges said:
typical hydraulic press consumes 5-7 KW electricity ... couple them to 100 KW PM generator.
Perperual motion machines do not work and are not discussed on PF. Thread closed

russ_watters

1. How does a hydraulic motor-AC generator coupling work?

A hydraulic motor-AC generator coupling works by using hydraulic power to rotate a motor, which in turn rotates an AC generator to produce electricity. The hydraulic fluid is pressurized and flows through the motor, causing it to rotate and drive the generator. This process allows for the conversion of hydraulic power into electrical energy.

2. What are the advantages of using a hydraulic motor-AC generator coupling?

One of the main advantages of a hydraulic motor-AC generator coupling is its efficiency. Since it utilizes hydraulic power to drive the motor, it can be more efficient than traditional mechanical systems. It also allows for precise control over the speed and power output, making it ideal for applications where variable speeds are necessary. Additionally, it can operate in a wide range of environments, including high temperatures and harsh conditions.

3. What are some common applications of a hydraulic motor-AC generator coupling?

A hydraulic motor-AC generator coupling is commonly used in industrial and commercial settings, such as in power plants, manufacturing facilities, and construction sites. It can also be found in various types of machinery, including cranes, excavators, and pumps. It is also used in renewable energy systems, such as hydroelectric power plants, to convert the energy of moving water into electricity.

4. Are there any maintenance requirements for a hydraulic motor-AC generator coupling?

Like any other mechanical system, a hydraulic motor-AC generator coupling requires regular maintenance to ensure its proper functioning. This includes regular inspections, lubrication of moving parts, and replacement of worn-out components. It is important to follow the manufacturer's recommended maintenance schedule to prevent breakdowns and ensure the longevity of the coupling.

5. How can a hydraulic motor-AC generator coupling be controlled?

A hydraulic motor-AC generator coupling can be controlled through various means, such as manual control valves, electronic control systems, or computerized control systems. These control systems allow for precise control over the speed and power output of the coupling, making it suitable for a wide range of applications. The type of control used depends on the specific needs and requirements of the system it is being used in.

Replies
6
Views
1K
Replies
19
Views
2K
Replies
4
Views
833
Replies
7
Views
2K
Replies
3
Views
2K
Replies
2
Views
1K
Replies
74
Views
3K
Replies
12
Views
4K
Replies
6
Views
2K
Replies
6
Views
1K