Custom Low-Frequency & Power Transformers
Mains and line-frequency power depends on the right transformer. P&A International engineers, prototypes and delivers custom toroidal, EI laminated, encapsulated & PCB-mount, R-Type and three-phase transformers — a few VA to multi-kVA, 50/60 Hz — built exactly to your voltage, regulation, isolation and compliance requirement.
As an engineering-led contract manufacturer founded as an engineering consultancy, we assign one dedicated engineer to your project from design review to qualified samples in 10–15 working days, then scale into volume through our vetted partner-factory network, where every supplier is ISO 9000 certified or better.
consultancy + manufacture
per project, end-to-end
qualified samples with test data
every supplier certified or better
one-off to high volume
Transformer types we make
Toroidal transformers
High efficiency, low stray field and low audible noise — ideal for audio, medical and instrumentation equipment. Compact, cool-running and quiet.
EI laminated & control transformers
Rugged, cost-effective designs for industrial power, control and general-purpose use. Multiple taps, classes of insulation and screen options.
Encapsulated & PCB-mount
Sealed, potted and board-level magnetics for moisture, vibration and safety-critical isolation. Reinforced insulation built to IEC 61558 as specified.
Three-phase transformers
For industrial machinery, renewable-energy systems and three-phase power conversion. Delta/star configurations, taps and screens to your spec.
We also build R-Type transformers — a compact, high-efficiency alternative to toroidal and EI where space and thermal performance matter.
Engineering capability
- Magnetic design & simulation — turns ratio, regulation, flux density, temperature rise and tolerances
- Core & lamination selection (silicon steel grade, toroidal, EI, R-Type) for efficiency and low noise
- Winding, taps, screens and multi-output design to your voltage and regulation targets
- Safety construction — creepage/clearance and insulation systems to IEC 61558 and EN 61558
- Encapsulation/potting and thermal-class selection for harsh environments
- DFM review to hit target cost while preserving performance
- Qualified samples with full test data before any volume tooling
- One dedicated engineer owns the project end-to-end
At a glance
| Types | Toroidal / EI laminated / R-Type / encapsulated & PCB / three-phase |
| Power | A few VA – multi-kVA |
| Frequency | 50 / 60 Hz line frequency |
| Phase | Single-phase & three-phase |
| Isolation | To CE/UL/IEC 61558; reinforced insulation available |
| Prototype | 10–15 working days to qualified samples |
| Quantities | One-off prototypes to high volume |
| Quality | Every supplier in our network is ISO 9000 certified or better |
Why engineers & buyers choose PA
For design engineers
A true design partner — one dedicated engineer, magnetic design and simulation, sample-before-production, and transformers optimised for efficiency, regulation, temperature rise and low noise. We design to your voltage, isolation and mechanical envelope — not just catalogue parts.
For purchasing
Low-risk scalability — predictable 10–15-day prototypes, flexible MOQ from one-off to production, target-cost DFM, a single point of contact, and a vetted ISO 9000+ partner network managed end-to-end by P&A. No hand-offs, no surprises.
3 easy steps to get started
Send us your spec
Send your voltages, VA rating and spec sheet. One dedicated engineer reviews it and confirms the technical details with you.
Proposed design & quote
You receive a proposed design and indicative pricing — typically within 48 hours — to review and refine together.
Samples & production
Qualified samples with full test data in 10–15 working days; on approval we scale into volume through our partner network.
Applications
Audio & consumer electronics · medical & laboratory instrumentation · industrial control & automation · lighting · renewable-energy & energy-storage systems · power distribution & general power conversion.
For switch-mode and high-frequency designs, see our high-frequency & switch-mode magnetics. Explore types in detail: toroidal, encapsulated and three-phase transformers.
Choosing the right power transformer
Getting the transformer right early saves costly re-spins later. A few decisions shape every low-frequency design — and sharing this detail lets us quote and prototype faster:
| Type first | Toroidal for low noise, low stray field and high efficiency (audio, medical); EI laminated for rugged, cost-sensitive power and control; R-Type where space and thermal headroom matter; encapsulated/PCB for sealed, board-level isolation; three-phase for industrial and renewable power. |
| Voltage & regulation | Primary and secondary voltages, taps, and the load regulation you need set the turns ratio, copper size and core. Tighter regulation means more copper and a larger core — we balance it against size and cost. |
| Temperature rise | Core and copper loss drive temperature rise and the insulation class (A/E/B/F/H). We select lamination grade, wire gauge and build to keep the part inside your thermal limit. |
| Isolation & safety | Creepage and clearance, the insulation system (reinforced or screened) and compliance to IEC 61558 / EN 61558, CE and UL are designed in from the start. |
| Mounting | Chassis, PCB, flying-lead or encapsulated — with the mechanical envelope, mounting and terminations to suit your enclosure and assembly. |
What to send us for a fast, accurate quote
The more of this you can share, the quicker we can return a proposed design and price:
- Primary and secondary voltages, VA rating and number of outputs
- Line frequency (50/60 Hz) and single- or three-phase
- Load regulation, taps and any screen requirement
- Isolation and safety requirements, and target standards
- Mechanical envelope — size, mounting, terminations — and thermal limits
- Target cost and annual volume or call-off pattern
- Any reference design, competitor part number or physical sample
Working from a competitor part or a sample is fine — our engineer will reverse-engineer it or design a drop-in equivalent to your specification.
📄 Download the transformer RFQ checklist & selection quick reference (PDF)
Get a quote
Send your voltages, VA rating, spec sheet or sample and one dedicated engineer will reply — typically within 48 hours — with a proposed design and indicative pricing. No project too big or too small.
One dedicated engineer reviews every enquiry and replies with a proposed design and indicative pricing. Your details are used only to respond to your enquiry. Prefer email? support@pa-international.com.au
Frequently asked questions
Which transformer type is right for my application?
What power ratings and voltages do you cover?
Can you build to UL, CE and IEC safety requirements?
Do you make encapsulated or potted transformers for harsh environments?
What are prototype lead times and minimum order quantities?
Low-frequency transformer types we design
Explore the full low-frequency range: toroidal transformers, EI laminated & control transformers, encapsulated & PCB-mount transformers, R-type transformers, three-phase transformers and current transformers. For switch-mode and ferrite designs, see our high-frequency & switch-mode magnetics.