What does a transformer do?
It steps voltage up or down between different sections of a power system, enabling efficient long-distance transmission while reducing voltage to safe, usable levels for industrial, commercial, or residential applications.
What is the difference between step-up and step-down transformers?
Step-up transformers increase voltage for efficient power transmission, helping reduce energy losses, while step-down transformers reduce voltage to suitable levels for industrial, commercial, or residential applications.
What is the difference between oil-filled and dry-type transformers?
Oil-filled: Uses mineral oil for cooling and insulation, making it suitable for outdoor and high-capacity applications. Dry-type: Uses air or resin insulation and is commonly preferred for indoor installations where reducing fire risk is important.
How do I determine the right transformer capacity?
Size the transformer based on the total connected load in kVA, while allowing an appropriate safety margin for future expansion and motor starting surges. MHS engineers can assist with detailed load calculations to ensure accurate and reliable transformer sizing.
What are mobile or rental transformers used for?
Temporary power during planned outages, substation maintenance, construction projects, or emergency replacement when permanent units fail. MHS provides rapid transformer rentals—typically within 24 hours for standard capacities.
How often should transformers be inspected?
Annually as standard. Oil-filled units: oil testing, insulation resistance checks, thermal imaging. Dry-type: insulation and mechanical inspection. Heavily loaded or critical transformers need more frequent checks.
What causes transformers to fail?
Overloading, poor ventilation, insulation degradation over time, moisture intrusion, or voltage surges/short circuits. Preventive maintenance catches early signs before failure.
Can transformers work outdoors?
Yes, particularly oil-filled units, which are weatherproof and well-suited for outdoor applications. Dry-type units are more commonly used for indoor installations or within protected enclosures where additional environmental protection is available.
Why does transformer efficiency matter?
Efficiency is the percentage of input power converted to output rather than lost as heat. Modern transformers achieve 98–99% efficiency, reducing energy costs and heat over their lifetime.
How long do transformers last?
With proper maintenance, transformers can typically last 25–35+ years, depending on loading levels, ambient conditions, operating conditions, and overall maintenance quality.
Can transformers be rented?
Yes. Mobile transformers are available for temporary needs—substation upgrades, event power, emergency replacement. MHS delivers, installs, and handles all technical support.
How do transformers work with generators?
A transformer steps the generator’s output voltage up or down to match the requirements of the load or distribution network and can also provide electrical isolation for improved safety during parallel operation.
Are transformers rated in kVA or kW?
Transformer capacity is typically rated in kVA, as it is based on apparent power rather than connected load power factor. Unlike generators, transformers are generally specified by kVA capacity rather than kW output.
How is transformer health monitored?
Key maintenance checks include oil quality and dissolved gas analysis for oil-filled units, thermal imaging, load monitoring, and insulation resistance testing. These help identify early signs of degradation and potential faults before they lead to equipment failure.









