Category: Yip Shing News

Diesel Generator Low Voltage? Analysing Failure Causes, Extending Generator Lifespan and Maintenance Methods

Posted on by Admin

Published on 19 December, 2025

With proper maintenance and an optimal operating environment can further extend the lifespan of Diesel Generators.
With proper maintenance and an optimal operating environment can further extend the lifespan of Diesel Generators.

Diesel generators are the core equipment in backup or primary power systems. When the unit experiences operational abnormalities, such as insufficient output voltage from the diesel generator, it can affect the operation of critical equipment. To ensure a stable power supply, operators need to understand the causes of diesel generator failures and the corresponding solutions. This article will analyse several common failure symptoms and causes, while breaking down the average lifespan of generators, helping you gain better direction in operation and maintenance.

Common Diesel Generator Failures and Cause Analysis

Diesel generators are widely used as primary or backup power sources in hospitals, factories, residential buildings, and data centers. Once a unit fails, it can prevent connected devices from functioning normally. Below are common diesel generator failure scenarios and potential causes to help you initially identify the root of the problem:

Failure Symptom Potential Causes
Unable to start or difficult to start Fuel supply interruption, low battery voltage, starter motor failure, engine damage, etc.
Shutdown during operation or abnormal output Clogged fuel filter, incomplete diesel combustion, leaks in oil or water circuits, cooling system abnormalities, low oil pressure, overload operation, etc.
Unable to stop after starting Solenoid valve stuck, control coil burned out, relay adhesion, abnormal ECU signals, etc.
Unstable output voltage or frequency Governor failure, AVR failure, coil short circuit, unstable engine speed
Abnormal AC voltage output Unstable engine speed, damaged AVR, stator winding open circuit, worn carbon brushes, etc.
Abnormal noise or vibration Worn parts, loose fixing bolts, damaged bearings
Abnormal exhaust smoke Black smoke is often due to excess fuel or clogged filters; white smoke is due to cold engine load or burned cylinder gasket; gray-white or blue smoke is often related to oil burning.

Since there are many causes of diesel generator failures, having basic knowledge can improve maintenance efficiency. Additionally, if the generator is supported by a professional after-sales service and technical team, issues can be resolved more quickly, significantly reducing downtime and minimizing impact on equipment operation.

What to Do If Diesel Generator Voltage Is Insufficient?

During operation, if the measured output voltage is below the rated value (The rated voltage is the normal output set during machine design, such as three-phase 400V or 380V), it indicates low diesel generator voltage, which requires immediate resolution. Common causes include:

  • AVR failure or incorrect settings are preventing the generator from providing sufficient voltage.
  • Open circuit, short circuit, or insufficient current in the excitation coil responsible for generating the magnetic field, failing to maintain the field needed to induce the rated voltage.
  • Loose or oxidized connection points in the diesel generator, causing a voltage drop and resulting in low
  • Poor contact or excessive wear on carbon brushes and slip rings, affecting current transmission.
  • Sudden connection of large loads with insufficient response performance, causing a temporary significant voltage drop.

Solutions

First, inspect, adjust, or replace the AVR to ensure the excitation system operates normally. Next, thoroughly check all connection terminals to rule out voltage drop issues caused by looseness or oxidation, and clean or replace worn carbon brushes and slip rings. If the temporary voltage drop is due to sudden large loads, improve the sequence of load startup, and confirm the sensitivity of the diesel engine governor to ensure the unit can quickly restore stable voltage and frequency.

How Long Is the Average Lifespan of a Diesel Generator?

Generally, well-designed and properly maintained medium to large industrial diesel generators have an average lifespan of over 8,000 hours, with some reaching 30,000 hours or even 50,000 hours. This means the unit can typically last 15 to 25 years. The actual lifespan depends on the generator model, size, and usage intensity, and can be further extended with proper maintenance and suitable operating environments.

Factors Affecting Diesel Generator Lifespan

Factors influencing diesel generator lifespan include:

  • Daily operating hours and load conditions: Long-term high-load operation accelerates component wear and shortens lifespan.
  • Environmental conditions: Harsh environments like high temperature, high humidity, dust, or corrosive gases accelerate part aging.
  • Maintenance frequency and consumable replacement: Timely replacement of engine oil, fuel filters, coolant, and air filters ensures normal operation.
  • Unit quality and manufacturing standards: Brand and design determine basic durability and performance stability.
  • Operating habits: Including correct startup and shutdown procedures, avoiding frequent premature power cuts or excessive operation.
  • Fuel quality and usage: Using poor-quality fuel can clog the injection system and cause component damage.

Choose High-Performance Cummins® Diesel Generators

We use globally renowned Cummins® generators, which are efficient, durable, and offer strong endurance, reducing the probability of issues like low diesel generator voltage or operational abnormalities, while comprehensively improving operational efficiency. Whether renting or purchasing generators, we provide complete pre-sales and after-sales services, including on-site surveys, transportation, installation and commissioning, as well as comprehensive maintenance and emergency support. This helps identify diesel generator failure causes, extend generator lifespan, and ensure stable power supply. Feel free to contact us— we will provide suitable generator products based on your needs and budget.

Diesel Generator Efficiency and Fuel Consumption: Principles, Uses and Advantages

Posted on by Admin

Published on 31 October, 2025

The principle of a diesel generator is to convert the energy released by diesel combustion into electrical power.
The principle of a diesel generator is to convert the energy released by diesel combustion into electrical power.

A reliable electricity supply is indispensable across all industries. When problems arise with the mains supply, or power is insufficient, a diesel generator serves as an emergency or even primary source of electricity. This is especially true for construction sites, large-scale events or critical facilities such as data centres, where dependable power provision has a direct impact on daily operations. This article outlines the principles, uses and advantages of diesel generators, and explains the factors influencing their efficiency and fuel consumption.

Principle of Operation

The central feature of a diesel generator lies in its effective conversion of the energy produced by diesel combustion into usable electricity. The operation takes place in two key stages:

Stage One: Diesel Engine Produces Mechanical Power

The principle behind a diesel generator is similar to that of an internal combustion engine found in vehicles. Its core is a diesel engine which generates mechanical energy through four repeating processes: Intake, Compression, Combustion and Exhaust.

1. Intake: The cylinder intake valve opens to admit fresh air into the engine.
2. Compression: The piston moves upwards, compressing the air within the cylinder and raising its temperature significantly.
3. Combustion and Expansion: At this high temperature and pressure, atomised diesel is injected into the cylinder, where it ignites spontaneously, causing a forceful explosion that drives the piston.
4. Exhaust: The piston rises again to discharge the combustion gases.

These processes repeat continuously, with the piston’s motion driving the crankshaft to rotate at a speed. This produces the steady mechanical energy required by the generator.

Stage Two: Conversion to Electricity

The mechanical energy generated by the engine is transferred to an alternator. The principle of electromagnetic induction is used: the engine rotates the internal rotor (a magnet) within a stationary set of windings (the stator), generating an electric current. This current is stabilised and regulated by a controller, ensuring a stable supply suitable for daily use.

Efficiency and Fuel Consumption

Two key indicators for evaluating a diesel generator are its efficiency and fuel consumption. How can one achieve maximum efficiency? How does one properly calculate fuel usage to keep operational costs under control? The following explains these issues:

Efficiency of Diesel Generators

Efficiency refers to the proportion of diesel’s chemical energy converted into electrical energy. Typically, diesel generators achieve a conversion rate of about 30% to 40%, depending on the model and load—It is more efficient than other types of power generation equipment (such as gasoline generators). Operating at consistently low or excessive loads can result in incomplete combustion of fuel, reducing efficiency and possibly causing damage to generator components.

Calculating Fuel Consumption

Many factors affect a generator’s fuel consumption—including unit output, load factor, engine technology and operational conditions. A commonly used formula is:

Fuel consumption (litres per hour) ≈ Power (kW) × Load factor (%) × Fuel consumption rate (g/kWh) ÷ 1000 ÷ 0.84 (fuel density)

For example, a 100 kW generator operating at 75% load with a specific fuel consumption of 220g/kWh would consume roughly:
100 kW × 75% × 220g/kWh ÷ 1000 ÷ 0.84 ≈ 19.6 litres per hour.

Larger generator sets generally achieve superior efficiency when operating at their optimum load. Selecting a generator of suitable output to meet practical needs is vital to controlling costs.

Main Advantages

Despite alternatives such as natural gas and solar power, diesel generators continue to be chosen in many sectors for the following reasons:

  • High reliability: Diesel generators can start rapidly and reach their rated capacity within seconds, providing an immediate emergency supply should the mains fail.
  • Greater fuel efficiency: Diesel has a higher energy density than petrol, providing more electricity per litre and lowering long-term fuel costs.
  • Durability and longevity: Diesel engines are robust, operate at lower speeds and experience less wear, so they typically outlast petrol engines when maintained correctly.
  • Relatively straightforward maintenance: Compared to natural gas systems, diesel generators are simpler to maintain and repair, and the necessary expertise is widely available.
  • Enhanced safety: Diesel has a higher flash point and is less volatile than petrol, making it safer to store and handle.

Two Principal Applications

In Hong Kong, diesel generators have broad applications as both standby supplies and main power sources:

Outdoor Power

Diesel generators provide dependable electricity for outdoor concerts, major events, temporary exhibitions, or construction sites not connected to the grid, enabling the continued use of equipment and preventing disruptions.

Emergency Back-up Power

In residential and commercial buildings, diesel generators are often installed as an emergency measure to keep fire safety systems, water supplies and other essential functions operational during power outages. Facilities where no interruption to power is tolerable—such as hospitals, data centres and telecommunications stations—rely on standby diesel generators for continuous protection.

Reliable Cummins Diesel Generator Series

Given the efficiency and advantages diesel generators provide for both primary and back-up supply, it is important to select machinery that is reliable and established. We offer a comprehensive range of generators by Cummins®, a globally respected manufacturer with nearly a century of experience in engine design. Cummins generators are renowned for high efficiency, durability and endurance. Each unit is thoroughly tested before sale, and after-sales support is available to ensure safety and reliability. If your business requires a dependable diesel generator, please contact us for hire or purchase.

Frequent Power Dips! Why Your Building Needs an Immediate Emergency Generator Inspection?

Posted on by Admin

Published On 12 April, 2024

Frequent Power Dips! Why Your Building Needs an Immediate Emergency Generator Inspection?

In recent weeks, unexpected voltage dips in multiple regions across Hong Kong resulted in several elevator entrapment incidents. The reason? Can be wildfire, thunderstorms, or even equipment faults. These incidents serve as an important reminder that unforeseen circumstances beyond our control, like natural disasters, can disrupt the stable supply of power.

To help reduce the potential impacts of power outages caused by external factors, buildings falling within certain criteria are required to install emergency power systems. The Hong Kong Fire Services Department (HKFSD) regulations stipulate that qualified buildings should be equipped with emergency generators, which should be capable of activating and providing electricity within 15 seconds upon the disruption of the main power source.

When unexpected power issues occur, emergency diesel generators integrated with an Automatic Transfer Switch (ATS) can help ensure the safe operation of elevators. The ATS is designed to detect power disruptions to the main power supply. When a power outage occurs, the ATS of the emergency diesel generator for elevators switches the power source, automatically supplying power to essential systems. Complementing this setup, the DeepSea 7320 genset controller has become a favoured choice for our diesel generators. Deployed in various local building projects, its trusted reliable control and monitoring capabilities have proven essential in ensuring a smooth transition during utility failures.

However, to prevent generators from failing to start or function properly, regular inspections and maintenance checks are crucial. It is important to check the battery status, gauge the fuel level and confirm the ATS’s proper functioning. At Yip Shing, we are committed to comprehensive safety checks and preventative care programs to keep your backup energy systems running smoothly. Our services include:

1. Regular generator repair and maintenance (monthly, quarterly, annually etc)
2. Provision of generator testing reports and maintenance reports
3. Replacement of generator parts and engine oil
4. Assembly of backup generator sets compatible with ATS systems
5. Generator rental to ensure stable power supply during power electrical replacements

If trapped in an elevator, don’t panic and alert building management using the alarm or intercom. Follow their instructions and wait for the rescue. Do not try to force open the doors or use the emergency hatch since this can be risky. Elevators are designed with safety features and communication systems. If needed, use the emergency contact numbers posted inside the lifts. Call “999” for immediate life-threatening situations. Remember, the safest action is to stay calm and wait for elevator technicians to arrive. Help comfort others until then.

While natural disasters are beyond our control, property management and elevator maintenance providers should have comprehensive emergency plans to ensure the safety and well-being of elevator passengers in unforeseen circumstances. Be proactive! Email us and schedule your generator inspection today.
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Joining the Lai See (Red packet) reuse and recycle program

Posted on by Admin

Published On 24 March, 2023

利是封回收重用大行動地球一小時2023

We’re more than just a company – we are passionate about sustainability and preserving our planet! Our team recently took part in a Lai See (Red packet) reuse and recycle program. We believe that small actions can make a big difference. That’s why we’re joining Earth Hour this Sat (25 March, 2023 at HKT20:30). It’s a global event reminding us all to take action to protect our planet. Join us to show some love to our Earth!