What Is a Low Frequency Transformer?
A low frequency transformer operates at power frequencies of 50 Hz or 60 Hz, and is used to step up or step down AC voltage in power distribution, isolation, and instrumentation applications. Unlike high frequency transformers that rely on ferrite cores, low frequency transformers typically use grain-oriented silicon steel laminations to handle the higher flux densities required at mains frequency.
Working Principle
An alternating current in the primary winding creates a time-varying magnetic flux in the laminated core. This flux induces a voltage in the secondary winding according to Faraday’s law. The turns ratio Np/Ns defines the voltage ratio, while the core cross-sectional area determines the maximum flux capacity at a given frequency.
Key Specifications Table
| Parameter | Typical Value | Note |
|---|---|---|
| Frequency | 50 / 60 Hz | Mains power frequency |
| Core material | Grain-oriented silicon steel | Low core loss at 50 Hz |
| Power range | 1 VA to 500 kVA | Depends on application |
| Efficiency | 95 – 98% | Load dependent |
| Insulation class | Class B / F / H | Thermal rating |
| Dielectric strength | 2 – 4 kV | Hipot test |
Selection Steps
Step 1: Define the VA rating and voltage ratio. Step 2: Select core material and lamination thickness based on frequency and loss budget. Step 3: Calculate core cross-section area and number of turns. Step 4: Choose winding wire gauge for current density. Step 5: Verify insulation and creepage distance for safety standards.
Applications
Low frequency transformers are widely used in power distribution transformers, isolation transformers for medical equipment, audio output transformers, uninterruptible power supplies (UPS), and grid-connected metering current transformers.
Sirui Technology Custom Low Frequency Transformers
Shaanxi SiRui Technology Co., Ltd. manufactures custom low frequency transformers with ISO9001 quality management, RoHS, REACH, SGS and CTI certification. We supply OEM and ODM transformer solutions with fast sample delivery for global buyers. Send your RFQ to sales@sirui-tech.com for quotation within 24 hours.
FAQ
Q: Can you make a 50 Hz isolation transformer with custom voltage rating? A: Yes, we produce custom low frequency isolation transformers from 1 VA to hundreds of kVA with any turns ratio. Q: What is the lead time for samples? A: Standard samples ship within 7-10 days. Q: Do you provide safety certification? A: Yes, we support CE, UL, RoHS and REACH compliance as required.