Frequently Asked Questions
Common questions on diesel generator sizing, canopies, ATS, maintenance, rental and export, with short answers on one page.
All the questions and answers from our site on one page. Each answer links to the page where the topic is covered in detail.
Products and solutions
What does an ATS panel do?
An ATS (automatic transfer switch) continuously monitors the mains. When the power goes out, it sends a start command to the generator and transfers the load to the generator once it is ready; when the mains returns, it transfers the load back to the mains and stops the generator after a cool-down period.
What amp rating should an ATS have?
The ATS is selected according to the generator's rated current. In a 400 V three-phase system, the current is found approximately with the formula kVA × 1.44; for example, a 155 kVA generator draws about 223 A, so the next standard rating up, a 250 A ATS, is selected.
Does the ATS come with the generator?
The ATS panel is a separate option, supplied with the set on customer request. It can be factory-tested and shipped together with the generator, or added to an existing installation later.
Why is a generator canopy important?
The canopy protects the generator from rain, dust and impacts, reduces operating noise and prevents unauthorised access. A well-designed canopy also ensures correct cooling airflow and easy access to service points.
Can a canopy be built for an existing generator?
Yes. By examining the generator's dimensions and the position of the radiator and exhaust, a canopy can be designed and manufactured to fit existing open-type sets. Please get in touch with us for details.
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Selection, sizing and installation
How important is the alternator brand in a generator?
The alternator is the part that converts the engine's mechanical power into electricity; voltage stability, behaviour during motor starting and performance with harmonic loads depend largely on the alternator. As important as the brand is that the alternator is sized correctly for the load and that spare parts, especially the AVR, are available in the region.
Which alternator can be chosen with which engine?
TA-series alternators (model codes TA…, e.g. TA160-10N2) are offered with all twelve engine brands in our line-up. Stamford and Mecc Alte can be chosen on sets with Perkins, Cummins, Baudouin, FPT Iveco, Scania and Volvo Penta engines, and Leroy-Somer on sets with Perkins, Cummins and FPT Iveco engines.
What is PMG excitation and when is it needed?
A PMG (permanent magnet generator) supplies the AVR independently of the alternator's output voltage. It is preferred for large motor starts, for loads that generate harmonics such as frequency drives and UPS, and in applications that require current to be sustained during a short circuit. The data sheet states which models it is offered on.
How many seconds after a power cut does the ATS switch to the generator?
It depends on the settings. In a typical diesel backup power system, the outage detection delay, starting the engine, letting voltage and frequency stabilise and the transfer itself are usually completed together in around 10–15 seconds. In critical facilities such as hospitals, the maximum permitted time is set by the relevant standards and regulations.
Should an ATS be 3-pole or 4-pole?
The decision depends on the facility's earthing system. A 4-pole ATS is used in systems where the generator neutral is earthed separately and the neutral must also be switched. In some systems where the neutral is earthed at a single point, a 3-pole ATS may be sufficient. The choice should be made by the engineer preparing the electrical design.
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Service, maintenance and rental
Does a standby generator that rarely runs still need maintenance?
Yes. In a generator that runs little, oil, fuel and coolant lose their properties over time, the battery weakens and water can collect in the tank. For this reason maintenance is based on the calendar as well as on running hours, whichever comes first.
How long does scheduled maintenance take?
It depends on the generator's power, the work to be done and the conditions on site. A routine service is usually completed on the same day; where parts must be replaced or a load test is needed, the duration is given to you in the service plan.
Do you service generators of other brands?
Yes. As well as sets built by Terex Diesel, we provide maintenance and repair for all generator brands. In your service request, simply give the generator's make, model, power and running hours.
In which regions do you provide scheduled maintenance?
Service is provided in the İstanbul and Ankara regions; for other locations, our team will contact you.
Is a maintenance contract required?
No. You can also request a one-off service. Under a maintenance contract the visit schedule is planned in advance and maintenance records are kept regularly. Details are on our generator maintenance contract page.
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Sectors
What size generator do I need for an irrigation pump?
It depends on the pump's motor power and its starting method. With direct-on-line starting, the motor draws about 3 times its running power at start-up; star-delta or a soft starter reduces this significantly. In our power calculator, select the pump power and starting type to see the recommended generator size.
What kind of generator suits use in the field?
A trailer-mounted set suits generators that will be moved between fields, while a canopied set suits one that stays at a fixed wellhead. A canopy that protects against dust and moisture, a large fuel tank and easy maintenance access all matter in farming conditions.
Which loads should a generator supply in a commercial building?
At a minimum, the loads needed for the safety of people and property, such as emergency lighting, fire pumps, lifts, and security and CCTV systems. If business continuity is required, HVAC, refrigerated cabinets and checkout systems are also connected to the generator.
Why do shopping malls use more than one generator?
With several synchronized generators, some can be taken offline at low load to save fuel, and the building is never left completely without power during maintenance or a breakdown.
What size generator does a construction site need?
The power is determined by the total load of tower cranes, concrete pumps, welding machines, compressors and site cabins, and above all by the starting power of the largest motor. A few tens of kVA may be enough for a small site, while large projects may need hundreds of kVA. Use our power calculator for a first estimate and contact us for exact sizing.
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Export and delivery
Which countries does Terex Diesel export generators to?
We ship the generators built at our facility in Türkiye to more than 100 countries. Our main markets include Libya, Tunisia, Algeria, Iraq, Azerbaijan, Georgia, Kazakhstan, Uzbekistan, Ukraine, the Balkan countries, Dubai (UAE), Tanzania and Argentina. If your country is not on the list, you can still ask for a quote.
What information should I give when requesting a quote from abroad?
Power (kVA), whether the generator will be backup or the primary source (standby / prime), voltage and frequency, open type or canopied, whether you need an ATS or synchronization panel, the fuel tank, and the highest and lowest temperatures and altitude at the site. With this information the first quote is right and needs no revision later.
Which documents are prepared for export?
The documents your customs and your project require are listed and agreed in writing at the quotation stage, before production.
What voltage and frequency should a generator in Dubai have?
The United Arab Emirates grid is 50 Hz, 230/400 V. The 50 Hz / 1,500 rpm ratings in our catalogue match this grid directly; we confirm the site voltage at the quotation stage.
Why does a generator lose power in the Gulf heat?
Hot air is thin; the engine takes in less oxygen and the radiator struggles to reject heat. On a set that will run above 45 °C this loss is significant. We choose the radiator for the highest temperature and move up one rating if needed.
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Company and contact
Where is Terex Diesel located?
Terex Diesel's 2,000 m² production facility is in Tuzla Leather Organised Industrial Zone (Deri OSB), Istanbul, Türkiye (Turkey). Every set is assembled and tested there.
What power range does Terex Diesel manufacture?
Diesel generator sets from 10 kVA to 4,125 kVA. The catalogue lists more than 600 models, all with the TRX model code, in canopied, open-type, trailer-mounted, containerised and dual-set versions.
Which engine brands does Terex Diesel use?
Twelve engine brands: Perkins, Baudouin, Cummins, FPT Iveco, Kofo, Kubota, Quartz, Scania, SDEC, Volvo Penta, Yangdong and Yuchai. The engine is chosen for the project's power, duty, fuel quality and service conditions.
Is every generator tested before shipment?
Yes. Every Terex Diesel generator is tested under full load at the Tuzla facility before it ships. Voltage, frequency, temperature and protection functions are checked during the test.
Does Terex Diesel export generators?
Yes. Terex Diesel has shipped generators from Türkiye to more than 100 countries. Shipping method, export documents and spare parts supply are agreed at the quotation stage.