Name: Standard Resistor Maintenance Bath Model 455
Brand: Isotech
SKU: 455

What is a standard resistor maintenance bath used for?

A standard resistor maintenance bath holds fixed standard resistors at a stable, uniform temperature so their resistance can be measured accurately. The Isotech Model 455 maintains resistance standards used with thermometry and resistance bridges, controlling from dew point to 40C with +/-0.005C stability.

What temperature range and stability does the Model 455 provide?

The Model 455 controls from dew point to 40C with +/-0.005C stability and gradients. Temperature differences total less than +/-0.015C measured directly in the oil and +/-0.003C measured inside a fixed standard resistor.

How many resistors can the Model 455 hold?

The bath houses several standard resistors at once, depending on their size, so you can maintain a bank of fixed standard resistors and measure their temperature coefficients together.

Why does the bath need special oil?

The bath oil must be very high resistance and very low viscosity. The wrong oil creates larger temperature gradients and can burn out the stirring motor. Isotech supplies the correct 35 liter fill as part number 932-19-72.

Can the Model 455 measure a resistor's temperature coefficient?

Yes. The bath can be programmed to step through a series of temperatures at a controlled ramp rate, so you can determine the temperature coefficient of a fixed resistor as well as hold it at a selected temperature.

What cooling technology does the Model 455 use?

The Model 455 uses solid-state Peltier chilling modules instead of a compressor, giving silent, vibration-free operation with minimal power consumption for a sensitive resistance-standards laboratory.

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Standard Resistor Maintenance Bath Model 455

Isotech Model 455 standard resistor maintenance bath with a fixed standard resistor and color control display

Alternative Views:

Precision oil bath that holds fixed standard resistors at a stable, uniform temperature for resistance metrology.

Dew point to 40°C operating range
±0.005°C stability and gradients (±0.003°C measured inside a fixed standard resistor)
Silent, vibration-free solid-state Peltier cooling
Houses several standard resistors; programmable stepping for temperature-coefficient work
Large color display, Ethernet and USB Host, data logging to USB

Product Code: 455

Product Description

Specifications

The Isotech Model 455 is a precision standard resistor maintenance bath that holds fixed standard resistors at a stable, uniform temperature for resistance metrology. It controls from dew point to 40°C with ±0.005°C stability and gradients, and temperature differences fall to ±0.003°C measured inside a fixed standard resistor. The result of many years of Isotech development, the 455 gives primary and secondary electrical laboratories a quiet, low-maintenance way to keep resistance standards at a known, repeatable temperature.

Who Uses the Model 455?
The 455 is built for national metrology institutes, primary electrical standards labs, and secondary calibration laboratories that maintain fixed standard resistors used with thermometry and resistance bridges. If you calibrate resistance standards or determine the temperature coefficient of resistance, the bath keeps every resistor at the same controlled temperature so your bridge readings reflect the resistor, not the room.

Silent, Vibration-Free Peltier Cooling
Heating and cooling are handled by efficient solid-state Peltier chilling modules that give optimal control around ambient. Solid-state cooling means minimal power consumption (150 W typical), silent operation, and no vibration, with no compressor and no expendable refrigerant to manage. That matters in a resistance laboratory, where mechanical vibration and compressor hum can disturb sensitive standards.

Stability and Uniformity for Resistance Standards
Stability and gradients are held to ±0.005°C, with 0.01°C control resolution. Measured directly in the oil, stability and temperature differences total less than ±0.015°C. Inside a fixed standard resistor that figure drops to ±0.003°C, because the resistor body integrates the small remaining gradients. This tight, uniform control is what separates a resistor’s true value from thermal effects.

Temperature-Coefficient Measurement and Control
The 455 does more than hold a set point. For work where you need to change the bath temperature to determine a resistor’s temperature coefficient, it can be programmed to step through a series of temperatures at a controlled ramp rate, and it houses several resistors at once depending on their size. A large color display, an Ethernet interface for remote monitoring, and a USB Host port make routine work simple, with data logging of both bath and air-intake temperature exported to a USB drive for your records and audit trail.

A Complete Resistance Metrology System
The 455 sits at the center of a resistance-standards workflow. It maintains the 456 fixed standard resistors that feed your thermometry bridge, works with the RBC Resistance Bridge Calibrator (including the Automatic Resistance Bridge Calibrator, A-RBC), and pairs with a microK² precision thermometry bridge for an end-to-end resistance and thermometry calibration chain backed by Isotech North America.

Ordering
Specify the operating voltage required (the supply is field-changeable between 100-130 and 208-240 Vac, 50/60 Hz) and the number and type of resistors you plan to house. The bath is supplied with the correct 35 liter fill of special high-resistance, low-viscosity oil (part number 932-19-72). Isotech North America supports the Model 455 with US-based sales, service, and NIST-traceable calibration.

Literature


455 Standard Resistor Maintenance Bath Datasheet