The TPU is a chassis-mounted thick-film power resistor series engineered for demanding high-voltage and high-power applications where non-inductive performance, broad resistance coverage, and long operational stability are required in a compact heatsink-mount package. Three models address different power levels: the TPU300 at 300W, TPU600 at 600W, and TPU800 at 800W, all rated at a bottom plate centre temperature of 85°C or below. Mounting the resistor’s bottom case directly onto a system heatsink is essential for achieving rated power — heat is conducted through the bottom case into the heatsink, and thermal management design should reference the bottom case centre temperature as the governing ambient condition.
The resistance range of 0.5Ω to 1MΩ is exceptionally wide, making the TPU series applicable across a broad spectrum of circuit functions — from low-impedance current limiting to high-impedance voltage divider and discharge networks. Tolerance options of ±1%, ±2%, ±5%, and ±10% allow the series to serve both precision and standard-duty roles, with a temperature coefficient of resistance spanning ±50ppm/°C to ±260ppm/°C depending on selected variant. The non-inductive thick-film construction suppresses series reactance that would otherwise degrade performance in switching and high-frequency power circuits, making the TPU suitable for gate resistors, snubber networks, and pulse-handling applications alongside its primary use in high-voltage power systems.
High-voltage capability is a defining characteristic of the TPU series. Insulation voltage is rated at 6kVdc to 10kVdc standard, with special-request variants available up to 12kVrms, and maximum working voltage stands at 5000Vdc. Insulation resistance is guaranteed at 10GΩ or above for the TPU300 and TPU600, and at 100GΩ or above for the TPU800, measured at 1000Vdc for one minute. These ratings confirm suitability for medium-voltage power electronics, high-voltage capacitor discharge circuits, and systems where creepage and clearance distances place stringent demands on the resistive component. Withstanding voltage is tested at both 6kVdc and 50Hz AC, ensuring compatibility with DC bus and mains-derived high-voltage environments alike.
Reliability across environmental stresses is validated by a comprehensive set of endurance requirements. Load life testing at rated voltage over 1000 hours (90 minutes on, 30 minutes off) limits resistance drift to ±(0.5%R+0.1Ω). Humidity resistance at 40°C and 90–95% relative humidity for 240 hours holds drift within ±(0.4%R+0.1Ω), and high/low temperature cycling across −55°C to +125°C for five cycles limits change to ±(0.2%R+0.1Ω). Short-time overload capability is rated at 1.5 times rated power for 5 seconds — 10 seconds for the TPU800 — with drift held to ±(0.2%R+0.1Ω). These characteristics collectively confirm the TPU as a high-stability component suited to continuous industrial duty.
Application note: The TPU series is well suited to power supply and control equipment where both high voltage and stable, predictable resistance are required in the same component. In automatic control and power electronics systems, the combination of non-inductive construction, wide resistance range, and high insulation voltage allows a single series to fulfil diverse circuit roles — from precision voltage dividers across high-voltage rails, to gate and snubber resistors in converter stages, to discharge and bleed resistors in high-voltage capacitor banks. The chassis-mount format and M5 screw terminals ensure secure mechanical and electrical integration into panel and rack-mounted systems, while the M4 mounting provision allows direct attachment to aluminium heatsink extrusions or cold plates for effective thermal management across all three wattage variants.
