How to parallel generators – A complete guide

  • Post last modified:January 5, 2023
  • Reading time:13 mins read

Paralleling generators involves synchronizing the generators to operate at the same frequency and phase and then connecting them together using the correct wiring and cables. Paralleling generators can be a complex and potentially dangerous process, so it is important to follow proper procedures and consult with a qualified professional if necessary. 

In this blog, we will provide a step-by-step guide for paralleling generators, as well as discuss this technique’s conditions, tools, and benefits.

Key Takeaways

  1. Paralleling generators involves synchronizing the generators to operate at the same frequency and phase and then connecting them together using the correct wiring and cables.
  2. Synchronizing generators refers to the process of connecting two or more generators together in such a way that they operate at the same frequency and phase.
  3. Specialized tools and equipment may be required when paralleling generators, such as a synchroscope, frequency meter, and protective gear.
  4. Paralleling generators require that the generators have similar ratings and are in good working condition.
  5. Paralleling generators can be a complex and potentially dangerous process, so it is important to follow proper procedures and consult with a qualified professional if necessary.

What is paralleling in generators?

Paralleling in generators refers to connecting two or more generators to work together to provide a single, larger output.

This is achieved by connecting the output terminals of the generators together, which allows the power from each generator to be combined and used simultaneously.

 

What is synchronizing in generators?

Synchronizing generators refers to connecting two or more generators in such a way that they operate at the same frequency and phase. 

This is necessary to ensure that the generators can operate together without causing damage to the system or disruptions to the power supply. 

Synchronizing generators typically involves using specialized equipment, such as a synchroscope or frequency meter, to measure the phase and frequency of each generator and adjust them as necessary. 

Once the generators are synchronized, they can be connected and operated in parallel to increase the total power output.

 

What are the conditions of paralleling generators?

There are several conditions that must be met to safely and effectively parallel generators. These include:

  1. The generators must be of the same type and have similar ratings and specifications, such as voltage, wattage, and frequency. 
  2. The generators must be in good working condition and properly maintained.
  3. The generators must be connected to a common load, such as a building or equipment, to distribute the power evenly. 
  4. The generators must be properly connected using the correct wiring and cables. 
  5. The generators must be properly synchronized to operate at the same frequency and phase. 
  6. The generators must be properly monitored and controlled to operate safely and efficiently.

Failing to meet these conditions can damage the generators and the electrical system, as well as safety hazards for those working with the equipment. It is essential to follow proper procedures and consult with a qualified professional if necessary.

 

Required Tools:

There are several tools that may be required when paralleling generators, depending on the specific circumstances and the type of generators being used. Some standard tools and equipment that may be needed include:

  1. Synchroscope or frequency meter: These tools are used to measure the phase and frequency of the generators and ensure that they are correctly synchronized before they are connected in parallel.
  2.  Wiring and cables: The generators must be properly connected using the appropriate wiring and cables. This may include cables for connecting the generators to the load and cables for connecting the output terminals of the generators. 
  3. Protective gear: When working with electrical equipment, it is essential to wear protective gear, such as gloves and safety glasses, to protect against electrical shocks and other hazards. 
  4. Monitoring and control equipment: To ensure that the generators operate safely and efficiently, it may be necessary to use monitoring and control equipment, such as ammeters and voltage.
  5. Portable power source: If the generators are being used in a remote location or in an emergency, it may be necessary to have a portable power source, such as a generator or a battery, to provide electricity for the tools and equipment being used. 
  6. Generator transfer switch: To switch reliably between the building’s primary power supply and the generators, a generator transfer switch may need to be built or purchased.

Having the appropriate tools and equipment to properly parallel the generators and ensure a safe and efficient operation is essential.

 

How to parallel generators – Step-by-step guide

  1. Start by gathering all of the necessary tools and equipment, including a synchroscope or frequency. If needed, the meter, wiring and cables, protective gear, monitoring and control equipment, and a portable power source. 
  2. Perform a visual inspection of the generators to ensure they are in good working condition and properly maintained. 
  3. Connect the generators to a common load, such as a building or a piece of equipment, using the appropriate wiring and cables. 
  4. Use the synchroscope or frequency meter to measure the phase and frequency of each generator and adjust them as necessary to ensure that they are properly synchronized. 
  5. Connect the output terminals of the generators together using the appropriate cables and wiring. 
  6. Turn on the generators and allow them to run for a few minutes to ensure that they operate properly. 
  7. Use the monitoring and control equipment to monitor the generators closely and ensure they operate safely and efficiently. 
  8. Make any necessary adjustments to the generators as needed. 
  9. If the generators are being used as a backup power source, use the generator transfer switch to switch between the main power source and the generators safely. 
  10. Once the generators are operating properly, use the total power output to meet the electricity demand. 

It is important to follow proper safety procedures and consult with a qualified professional if necessary.

 

How do parallel generators share the load?

When multiple generators are connected in parallel, they can share the load by dividing the total power demand among themselves. This is typically achieved through the use of load-sharing equipment, which monitors the power output of each generator and automatically adjusts the load on each generator to ensure that they are operating at their maximum capacity.

For example, if the total power demand is 1000 watts and two generators are connected in parallel, each generator will be assigned a load of 500 watts. Suppose one generator can produce more power than the other.

In that case, the load-sharing equipment will automatically redistribute the load so that each generator operates at its maximum capacity. This can help ensure that the generators operate efficiently and provide a reliable power source.

It is important to note that load sharing only works when the generators are properly synchronized and connected in parallel.

If the generators are not synchronized or not connected properly, they may not be able to share the load evenly, which can result in damage to the generators and the electrical system.

 

What happens if two generators are not synchronized?

If two generators are not properly synchronized, they can cause a number of problems. The most serious problem is that they can create a power surge, which can damage equipment and potentially cause a fire.

In addition, if the generators are not synchronized, they may not be able to provide a stable power supply, which can cause issues with sensitive equipment. 

Furthermore, running two un synchronized generators can be inefficient, as they may need help to operate at their full potential. It is important to synchronize generators to ensure they can operate safely and efficiently properly.

 

Can we synchronize two generators of different frequencies?

Yes, it is possible to synchronize two generators of different frequencies. 

However, it requires the use of special equipment, such as a frequency converter, to adjust the output of one generator to match the other. 

This can be a complex and expensive process, so it is generally only recommended if absolutely necessary. It is always best to use generators with the same frequency to avoid potential issues.

Related: Can you parallel two non-inverter generator?

 

Problem associated with paralleling AC generators

One of the main problems associated with paralleling AC generators is that it can be difficult to ensure that the generators operate at the same frequency and phase. 

This is because the frequency of an AC generator is determined by the speed at which the generator’s rotor turns. Small differences in the speed of the generators can cause significant differences in the output frequency. 

This can make it difficult to synchronize the generators, and if they are not properly synchronized, they may not be able to be safely connected.

A few other problems are

  1. Difficulty in synchronizing the generators: As mentioned earlier, it can be difficult to ensure that the generators operate at the same frequency and phase, making it difficult to connect them safely. 
  2. Uneven load distribution: It can be challenging to evenly distribute the load among the generators, which can reduce the system’s overall efficiency. 
  3. Potential for damage to the generators: If the generators are not properly synchronized and connected, there is a risk of damage to the generators and other components of the power system. 
  4. Increased complexity: Paralleling multiple generators can add complexity to a power system, making it more challenging to operate and maintain. 
  5. Increased cost: Paralleling multiple generators can be more expensive than using a single, larger generator due to the additional equipment and labor required.

 

Can I safely parallel two identical AC generators to get 240V?

It is generally not recommended to parallel two identical AC generators to get 240V, as this can be a complex and potentially dangerous process. 

To safely parallel two AC generators, they must be properly synchronized and connected, which requires specialized equipment and expertise.

It is typically best to use a single, larger generator that is capable of providing the desired output voltage rather than attempting to parallel multiple generators.

Additionally, it is important to carefully consider the load the generators will be expected to handle and ensure that the generators are properly sized and rated for the intended application. 

It is always best to consult with a qualified electrician or other experienced professional before attempting to parallel AC generators.

FAQs

It is generally possible to parallel different-size generators, but it can be a complex and potentially dangerous process. To safely parallel generators of different sizes, they must be adequately synchronized and connected, which requires specialized equipment and expertise.

It is possible to run multiple generators in parallel, but whether or not you can run two generators from different brands at the same time will depend on the specific generators and the setup of your system.

It depends on the type of generator and how it is set up. In general, running two generators in parallel can increase the amount of power they can produce, but it will not necessarily double the wattage. This is because each generator has its own maximum output, and the combined output of the two generators will be limited by the lower of the two outputs.