Industrial Control for Genset and Basic Genset Design
The genset market is booming. The genset market was estimated at $20.93 billion in 2018 and is expected to increase to $27.24 billion by 2023.
One big reason for the uptick in sales is due to the myriad industries who need generators to help them keep their business running 24/7. And it’s not just heavy industries that are increasingly relying on generators.
But not everyone knows what a genset is. Nor do they understand what it does or what its basic design is. Keep reading to learn everything you need to know about a genset generator.
What a Genset Is
A genset is also known as a generator set. It’s a piece of equipment that’s portable.
It consists of an engine and an alternator/electric generator. It’s used to provide energy.
How Gensets Work
Generators are a combination of a prime mover, which is typically an engine, along with an alternator. The engine converts the mechanical energy which is obtained from an external source into electrical energy as the output.
The mechanical energy is used to spin the alternator rotor, which converts mechanical energy into electrical energy. Generators do not create electrical energy.
Generators Force the Movement of Electrical Charges
Instead, gensets use the mechanical energy that’s been supplied to it to force the movement of electrical charges. Those electric charges are present in the wire of its winding through an external electrical circuit.
The alternator is made of two main parts which are the rotor and stator. When the alternator rotor is spun through the magnetic field between the toro and stator, it creates a voltage on the alternator stator.
The flow of electric charges creates the output electric current provided by the generator. Michael Faraday discovered the principle of electromagnetic induction with which today’s generators work on.
Generators Produce a Great Deal of Heat
Converting mechanical energy to electrical energy produces a tremendous amount of heat. It’s vital the interior components are instantly cooled to prevent damage to the generator.
Most gensets are either hydrogen cooled, air cooled or liquid cooled. Which type of cooling system is used depends on the size and type of the generator.
Smaller generators typically use air cooling systems which don’t reject heat as quickly as hydrogen or liquid cooling systems do. The most efficient method for large generators is hydrogen cooling.
Parts of a Generator
The engine provides the source of the input mechanical energy to the genset. How much power output the generator supplies is directly proportional to the size of the engine.
When considering engines for generators consult with the manufacturer to get engine operation specifications and maintenance schedules.
An alternator works with the battery to generate power for the electrical components of the genset. There are both stationary and moving parts within the alternator.
All parts work together to cause relative movement between the electric and magnetic fields. This is what generates electricity.
There are different types of alternators used in gensets. To select the right type of alternator, it’s necessary to define the purpose of your needs and the working conditions.
- Fuel System
Fuel tanks should typically be able to keep generators running for six to eight hours. In smaller gensets, the fuel tank is part of the generator’s skid base or is mounted on the generator frame.
In larger, commercial generators, external fuel tanks may need to be erected and installed. Those are subject to the approval of local officials.
Type of Fuel Used
Generators can run using a variety of fuels such as:
- Natural gas
- Propane (liquid or gaseous forms)
Smaller engines typically run on gas while larger engines use either liquid propane, propane gas, natural gas or diesel. Some engines can also operate using a combination of diesel and gas in a bi-fuel operation mode.
- Voltage Regulator
The voltage regulator takes a tiny portion of the gensets output of the AC voltage. It then converts it into a DC current.
Next, the voltage regulator feeds the DC current to the exciter windings.
Maintains an Equilibrium When at Full Capacity
This cycle continues until output voltage equivalent capable of operating at full capacity is generated. As output increases, the voltage regulator produces less DC current.
At full operating capacity, the voltage regulator maintains a state of equilibrium.
- Cooling and Exhaust System
Check coolant levels daily. Flush the cooling system and raw water pump every 600 hours. Clean the heat exchanger after every 2,400 hours of operation. Follow the National Electric Code to ensure a free flow of cooling air.
Some generators use fresh/raw water as a coolant. However, that’s more typical for small generators in city applications or large units over 2250 kW.
Hydrogen, Radiators, and Fans
Hydrogen is used for the stator windings in large generators. It’s more efficient at absorbing heat.
For all gensets, a standard radiator and fan are mounted on the generator. It works as the primary cooling system.
- Lubrication System
Lubrication ensures durability and smooth operations over long periods of time. Oil is stored in a pump to lubricate the engine.
The lubricating oil should be checked every eight hours during operation. Every 500 hours, check for leakages and change in the oil!
- Battery Charger
The start function is battery-operated. The battery charger charges the generator battery by supplying it with precise float voltage.
A low float voltage means the battery is undercharged. High float voltage shortens the life of the battery.
Most battery chargers are made from stainless steel to prevent corrosion. They’re fully automatic and require no adjustments.
- Control Panel
The control panel acts as the “brains” of the genset. It controls the genset operation, monitors and protects it.
There are several industrial control products used in the genset control panel and on the generator itself.
Each generator differs in its ability to withstand electrical overloads and fault currents. Circuit breakers protect generators from this happening. Depending on the size and purpose of the generator, the circuit breaker can be a simple push button switch type, an MCB (Miniature Circuit Breaker, or an MCCB (Molded Case Circuit Breaker).
HMI (Human Machine Interface)
The Human Machine Interface acts as the operator interface to the control system. An HMI can be a series of push buttons, switches, pilot lights or an HMI graphical display. “HMI” typically refers to the graphical display.
The HMI application software allows users to monitor both historical and live operating data, alerts to alarms and provide maintenance alerts.
Pilot devices include:
- Selector switches
- Indicator lamps
- Toggle switches
Gauges are used alone on simpler gensets or in conjunction with an HMI on larger, more complex systems. These indicate certain parameters such as:
- Battery voltage
- Duration of operation
- Engine rotation speed
- Oil pressure
- Temperature of coolant
Constant monitoring allows the built-in shutdown component to take over when they’ve crossed their threshold levels.
Terminal blocks connect, terminate and/or secure wires. They are several individual terminals that are arranged in a long strip.
Using an electrical signal, electromagnetic relays are the components that control switching of circuits in a generator. Relays are the link between the lower power input to the high-power output.
The disconnect switch quickly disconnects the genset from power and is a vital important safety feature.
A PLC (programmable logic controller) is an industrial computer control system. It’s there to continuously monitor the performance of the generator and manage its parameters.
- Base Frame
The base frame is the steel frame that includes an anti-vibration system. It is the skid on which all parts of the genset is mounted. By mounting everything on this steel or aluminum plate, the genset is made portable.
The base frame may also serve to raise the generator to a certain height that is specific to the customer’s requirements.
Depending on the user’s requirements, the genset can be enclosed within a cabin, for both soundproofing and protection from elements.
Automatic Transfer Switch
The automatic transfer switch is responsible for the alternation between the main source and the auxiliary source, the genset. This ensures a continuous supply of electricity should one source fail.
Benefits of a Genset
There are many benefits to a well-built, industrial quality genset such as:
- Automatic loading control
- Automatic or manual paralleling
- Fuel efficiency
- Local or remote operation
- Low emissions
- Scalable design
Gensets are also easily transportable whether they need to travel by land, sea or air. Most are designed with minimal interfaces to ensure rapid installation and global commissioning.
Many units can also be combined into scalable blocks.
Industries Who Rely on Gensets
There are a great many industries that rely on a genset generator to keep them running smoothly no matter what, such as:
- Building management
- Food processing
- Government and state services
- Hospitality and tourism
- Power plants and energy
Even labs, farming facilities, and healthcare offices often rely on gensets to ensure they can continue working even during power outages or power shortages.
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