Overload transformers are primarily used in scenarios where there are short-term, periodic high load demands. Their core function is to cope with equipment start-up shocks, power consumption peaks, or emergency loads, preventing ordinary transformers from tripping or being damaged due to short-term overload. At the same time, there is no need to excessively expand capacity for occasional peak loads.

1. Classification of core application areas

1. Industrial manufacturing field (main scenario)

Industrial equipment often experiences “starting surge currents” or “short-term process overloads,” and overload transformers can accommodate these intermittent high-load demands.

Motor drive scenarios: When equipment such as machine tools, fans, water pumps, and compressors are started, the current can reach 3-5 times the rated value (for example, a 10kW motor requires 30-50kW of power at the moment of startup). An overload transformer can withstand this short-term surge, preventing tripping during startup.

Heating process scenarios: Plastic molding machines, high-frequency quenching equipment, etc., require short-term high power during the heating and temperature rise phase, and return to low power during the heat preservation phase. Overload transformers can match the load characteristics of “high-low power cycling”, reducing the overall cost of the equipment.

In heavy machinery scenarios, such as cranes and crushers, short-term overload may occur during the lifting of heavy objects or crushing of hard materials. An overload transformer can ensure stable operation of the power system and prevent shutdown due to load fluctuations.

2. Power distribution and emergency response

In the power system, there is often “peak-valley fluctuation” in electricity load. Overloaded transformers can handle short-term overload during peak hours, reducing the pressure on the expansion of the distribution system.

Civil power distribution scenario: During peak electricity usage periods in residential areas and commercial complexes (such as during the summer when air conditioners are turned on en masse or during the winter when heating equipment is operating at full capacity), the load on the distribution transformer may temporarily exceed its rated value. An overloaded transformer can withstand 1.2-1.5 times its rated load (typically for 1-2 hours), thus avoiding widespread power outages.

Emergency power supply scenarios: In hospitals, standby power supplies and emergency power supply systems in data centers may experience short-term fluctuations in load during the instantaneous switch between primary and standby power sources. Overloaded transformers can stabilize the voltage, preventing emergency equipment (such as ventilators and servers) from shutting down due to unstable voltage.

Temporary power supply scenarios: temporary electricity usage at construction sites, and temporary power distribution for outdoor events/activities, where loads are random (such as electric welding machines, temporary lighting, and air conditioners starting simultaneously). Overloaded transformers can handle sudden high load demands, enhancing power supply reliability.

3. Transportation sector

The power system or supporting equipment of transportation vehicles often experiences short-term overload due to changes in operating conditions, requiring an overload transformer for adaptation.

Regarding new energy vehicles: During the initial charging phase (fast charging stage), charging piles will output a short-term high current (for example, a peak power of 120 kW for a fast charging pile, with a short-term overload up to 150 kW). An overload transformer can meet this demand while avoiding losses caused by long-term high-power operation.

In the field of rail transit: When subways and light rails accelerate or ascend slopes, the traction system requires short-term high power (for example, the rated power of the traction transformer is 200 kW, but it needs to be over 300 kW during startup). The overload transformer can match the power demand and ensure smooth operation.

In the fields of shipping and aviation: The propulsion system of ships, deck machinery (such as cranes), or aircraft ground power supply equipment may experience short-term overload under specific operating conditions (such as ship unloading at port or aircraft ground maintenance power supply). Overload transformers can ensure the normal operation of the equipment.

4. Special equipment and people’s livelihood

Some special equipment or public facilities, due to their functional requirements, experience short-term high loads and require the support of overload transformers.

Special processing equipment: electric welding machines, laser cutting machines, etc. During welding or cutting, the current/power increases sharply (for example, an electric welding machine with a rated power of 10 kW may experience a short-term overload to 20 kW during welding). An overload transformer can prevent the equipment from frequent restarts or damage.

In the field of medical equipment, medical devices such as CT machines and magnetic resonance imaging (MRI) require short-term high power at the moment of startup or scanning (for example, the power of MRI can reach 80 kW during startup, with a short-term overload of 100 kW). An overload transformer can ensure stable operation of the equipment and avoid affecting the diagnosis and treatment process.

In the field of agricultural production, large irrigation pump stations and grain dryers may experience short-term overload due to the simultaneous startup of multiple devices during peak irrigation or drying seasons. Overload transformers can address this demand and ensure the progress of agricultural production.

II. Core commonalities of application scenarios

The key criteria for selecting an overload transformer essentially revolve around the following characteristics of the load:

Overload is short-term: the duration of overload is usually from a few minutes to a few hours, and it will not remain in a state of exceeding rated load for a long time (otherwise, it will cause overheating and damage to the transformer).

Overload is either periodic or sporadic: such as motor startup, peak electricity usage, etc. Load fluctuations occur regularly or are not continuous, so there is no need to configure an ordinary transformer with an excessively high rated power for peak loads.

Impact load exists: When the load starts or the operating conditions change, instantaneous high current/high power will be generated. Ordinary transformers are prone to tripping due to the impact, while overload transformers can withstand this impact.