# 3265B/25A Wayne Kerr DC Bias Unit New ## Wayne Kerr 3265B/25A DC Bias Unit — Key Features at a Glance - **DC bias current:** up to 25 A, set in 25 mA steps (single-unit configuration) - **Compatible analyzers:** 3260B Precision Magnetics Analyzer, 3255BQ, 3255B Inductance Analyzers - **Parallel operation:** up to five 3265B units may be connected in parallel to deliver up to 125 A DC bias current (50 A maximum when paralleled on the 3255BL) - **Maximum compliance voltage:** 11 V DC at 0.25 V AC drive level; 10 V at 1 V AC drive level (f > 12 kHz deduct 0.5 V) - **Variables measured (impedance mode):** L, Z, R, Q, D - **Basic accuracy:** ± 1% (varies with measurement speed, frequency and options chosen) - **Safety & protection:** bias safety interlock socket, 1.6 A measurement-terminal fuses, over-temperature trip, and protection against excess voltage drop and sense lead failure - **Order code:** 1J3265B/25A Processed / reviewed In summary, the Wayne Kerr 3265B/25A is a 25 A DC Bias Unit, an ancillary instrument used in conjunction with Wayne Kerr 3255B-series Inductance Analyzers and the 3260B Precision Magnetics Analyzer. It delivers DC bias current to a wound component under test — inductors, transformers, and chokes — so that L, Z, R, Q, and D can be measured at the operational bias point rather than at the small-signal limit. Current is programmable in 25 mA steps to a maximum of 25 A per unit; multiple units may be paralleled to extend the range up to 125 A DC. ### What is the Wayne Kerr 3265B/25A DC Bias Unit used for? Choose the 3265B/25A for high-current wound-component characterization with the 3255B or 3255BQ Inductance Analyzers, or with the 3260B Precision Magnetics Analyzer when extended 3 MHz bandwidth is not required. Typical applications include SMPS choke saturation testing, three-phase inductor characterization, and DC bias sweeps on EV powertrain magnetics. ### How does the 3265B/25A connect to the analyzer? The 3265B/25A connects to the host analyzer through four BNC-to-BNC links (supplied) for the AC measurement signal path, an I²C bus link for DC current control and status reporting, and a rear-panel bias safety interlock socket that provides door-lock and closed-control-line monitoring. Connection to the component under test is via 2-terminal M8 studs, or via 4-terminal Kelvin leads (Wayne Kerr fine-jaw 1EVA40100 or large-jaw 1EVA40180) for highest accuracy. The unit powers up automatically when the host analyzer is powered on. Factually, the 3265B/25A provides DC bias current in 25 mA increments from zero to 25 A. With basic ± 1% accuracy, an 11 V DC compliance voltage at 0.25 V AC drive level, and a universal 90–255 V AC, 47–63 Hz input, the unit is rated for full accuracy over 15 °C to 30 °C at maximum rated current. The I²C bus link continuously monitors excessive voltage drop and over-temperature status during measurement. Wayne Kerr is recognized in the precision-impedance measurement industry alongside Keysight (E4990A, E4980A) and Hioki (IM3536) as a primary brand for inductor and transformer characterization. The 3265B family extends the 3260B and 3255B-series analyzers into the high-current DC-bias regime that defines real-world power-magnetics behavior — saturation, DC-bias-dependent inductance, and Q degradation under load. Typical use cases for the 3265B/25A include: - Characterizing SMPS chokes and PFC inductors at their full operating DC bias current to verify the published L vs. I curve - EV powertrain magnetics qualification — DC-link chokes, common-mode chokes, and traction inductors at realistic continuous bias - High-current transformer qualification including bias-dependent leakage inductance and core loss - Pre-compliance inductance measurements where the supply designer needs to confirm L(I) holds across the converter's operating current range ## Accessories Supplied All units are supplied with user manual, power cable, spare fuses, 4 × BNC to BNC links and daisy chain control link. ### Optional Accessories (Order Codes) Accessory Description Order Code Kelvin clip leads (fine jaws) **1EVA40100** Kelvin clip leads (large jaws) **1EVA40180** Power transfer bus bars **4-324-6009-PAIR** Filter pad (washable) **HMDEC10** 1009 DC bias fixture **1J1009** 1009 50A lead set **5-328-2005** ## Wayne Kerr 3265B/25A — Core Specifications The 3265B/25A must be used in conjunction with a compatible host analyzer. The specifications below are reproduced verbatim from the Wayne Kerr Technical Data Sheet covering the 3265BQ/25A, 3265B/25A, 3265B/10A, 3265B/5A DC Bias Units and the 1009 DC Bias Fixture. DC Bias Current — Rated 25 A maximum per unit, programmable in 25 mA steps DC Bias Current — Paralleled Up to 5 units in parallel for up to 125 A DC (25 mA steps). On the 3255BL: up to 50 A maximum. Compatible Host Analyzers 3260B Precision Magnetics Analyzer, 3255BQ, 3255B Inductance Analyzers Measurement Frequency Range (when paired) 20 Hz to 1 MHz with 3255BQ. 20 Hz to 500 kHz with 3255B. Operates with 3260B Precision Magnetics Analyzer. Compliance Voltages Maximum compliance voltage (<12 kHz) 11 V DC at 0.25 V AC drive level. 10 V compliance at 1 V AC drive level. For f>12 kHz deduct 0.5 V. Variables Measured In impedance mode: L, Z, R, Q, D. Not applicable to Rdc, or transformer measurements. Basic Accuracy ± 1%. Varies with measurement speed, frequency and options chosen. Measurement Terminals 2-terminal measurement via M8 studs. 4-terminal measurement via Kelvin leads and M8 studs. Measurement terminals internally protected by 1.6 A fuses against normal inductor back-EMF or accidental disconnection of inductor. Front panel fuses easily replaced. Interlock Bias safety interlock socket on rear panel of analyzer provides door lock and closed control lines. Control Connections I²C bus link controls application of DC current and monitors status of analyzer. Status data includes excessive voltage drop and over temperature. Optional Facilities 3265B bias units may be connected in parallel to give five times the rated current. Temperature Range Storage: −40 °C to 70 °C. Operating: 0 °C to 40 °C, 20 A (3265BQ/25A and 3265B/25A). Full accuracy: 15 °C to 30 °C (at maximum rated current). Power Supply Universal 90 to 255 V AC, 47 to 63 Hz. Input current 9 A rms max. Power factor >0.9. Unit powers up automatically when connected to a powered analyzer. Isolating switch provided. Cooling Fan cooled. Intake front, exhaust rear. Fan filter accessible on front panel. Over-temperature trip provided. Dimensions & Weight Height 190 mm (7 1/2"), Width 440 mm (17 3/8"), Depth 520 mm (20 1/2"). Weight 15 kg (33 lb). Applications Permits measurement analysis of wound components with levels of DC bias current higher than the standard 1 A. **⚠ Important — Host Analyzer Required** The 3265B/25A is an ancillary instrument and does not function as a standalone meter. It must be operated with a compatible Wayne Kerr host analyzer as listed above. The 3255BL may **only** be used with the 3265B/5A and 3265B/10A. For extended 3 MHz operation with the 3260B, the 3265BQ/25A variant is required. **⚠ Important — Kelvin Leads & High-Current Hardware** 4-terminal Kelvin measurement requires Kelvin clip leads — fine-jaw (**1EVA40100**) or large-jaw (**1EVA40180**). For paralleled-unit configurations, **Power transfer bus bars (4-324-6009-PAIR)** are required to safely carry the high combined currents between units. Contact your Test Architect to confirm the correct lead and bus-bar configuration for your application. This webpage was written by a human with an A.I. "Intern", which may contain errors. Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer. ## Details - **Price:** 0.0 USD - **Vendor:** Wayne Kerr - **Type:** Ana Oth - **Tags:** Analyzers, Manufacturers, Other, product_manual_group_1, Product_new, Wayne Kerr ## Variants | Variant | Price | Available | |---------|-------|-----------| | Default Title | 0.00 USD | In stock | --- > Source: [ValueTronics](https://valuetronics.com/products/3265b-25a-wayne-kerr-dc-bias-unit-new) > Updated: 2026-05-19