Isotech 455 Standard Resistor Maintenance Bath

The Isotech 455 Resistor Maintenance Bath has been specially developed for the long-term and extremely stable conditioning of standard resistors used in thermometric bridges and advanced resistance measurement setups. Thanks to years of development and practical experience, this bath offers an exceptional combination of stability, uniformity, and ease of use. The instrument is ideal for laboratories that want absolute control over the temperature of their reference resistors, or that want to determine the temperature coefficient of fixed resistors.

Designed for maximum stability

The 455 bath uses efficient solid-state Peltier modules for both heating and cooling. This technology ensures extremely accurate temperature control around the ambient temperature, with minimal energy consumption, quiet operation, and complete absence of vibration. Temperature stability is ±0.005 °C, while total temperature differences in the bath remain less than ±0.015 °C when measured directly in the oil. Within a fixed standard resistor, stability is even better than ±0.003 °C. This performance makes the bath particularly suitable for measurements where even the smallest temperature variations affect the resistance.

Large capacity for multiple resistors

The bath offers sufficient space to place multiple standard resistors simultaneously, depending on their dimensions. This allows laboratories to work efficiently and condition multiple references in parallel. The system is also ideal for determining temperature coefficients, whereby the bath temperature is varied in a controlled manner. The liquid in the bath plays a crucial role. Isotech supplies a specially developed oil with very high electrical resistance and low viscosity, which is essential for minimizing temperature gradients and protecting the internal circulation motor. Using unsuitable oil can lead to poorer performance or even damage to the system.

Modern operation and advanced control

The latest generation of the 455 is equipped with a large color display with clear graphics. The interface is designed for intuitive operation and provides direct access to all settings and measured values. The Ethernet interface allows remote monitoring of the bath temperature, which is ideal for automated laboratories or long-term stability measurements. For applications where the temperature needs to be varied—for example, to determine TCR values—the bath can be programmed to automatically cycle through a series of temperatures at a controlled ramp rate. In addition, the system records both the bath temperature and the air inlet temperature. This data can be easily exported to a USB stick for further analysis or archiving.

Robust construction and practical dimensions

The 455 bath is built for intensive use in professional laboratories. Its construction is sturdy, thermally efficient, and designed for long-term reliability. With a height of 910 mm, a width of 635 mm, and a depth of 710 mm, the bath offers a spacious internal capacity without taking up unnecessary floor space. The total weight is 66 kg, which contributes to the stability of the system. The bath operates at 150W typical and supports both 100–130 V and 208–240 V, with the voltage configuration adjustable in the field.

Applications

The Isotech 455 is ideal for:

> Conditioning standard resistors for thermometric bridges
> Investigating temperature coefficients of fixed resistors
> Use in combination with the Automatic Ratio Bridge Calibrator (A‑RBC)
> Long-term stability measurements under controlled conditions

Thanks to its combination of stability, flexibility, and modern controls, the bath is suitable for both primary and secondary laboratories. The Isotech 455 Resistor Maintenance Bath provides an exceptionally stable and accurate environment for maintaining and characterizing standard resistors. With its modern controls, quiet operation, programmable temperature profiles, and solid construction, it is a reliable and future-proof solution for laboratories that require absolute temperature control for their resistance standards.