Winding Resistance Test Equipment & Micro-Ohmmeters
ED&D winding resistance test systems and micro-ohmmeters support transformer winding temperature determination, coil evaluation, and low-resistance measurement. The HOT-30 provides multi-channel resistance and thermocouple measurement for transformer winding temperature evaluations, while the 4176 Micro-Ohmmeter measures resistance from 1 µΩ to 30 kΩ using a four-wire Kelvin connection.
Multi-Channel Transformer Testing
The HOT-30 combines multiple resistance and thermocouple channels for
transformer temperature-rise evaluations.
Four-Wire Kelvin Measurement
The 4176 micro-ohmmeter measures resistance from
1 µΩ to 30 kΩ using a four-wire Kelvin connection.
Provide the equipment type, expected resistance range, number of windings or measurement points, required temperature inputs, test procedure, and data-output requirements.
Transformer Winding and Low-Resistance Measurement
Winding resistance and low-resistance test equipment is used to evaluate transformer windings, coils, conductive paths, and low-resistance electrical connections during design verification, safety testing, component evaluation, and production testing.
The winding-resistance method is used to calculate average winding temperature from cold and hot resistance measurements using the calculation and timing requirements specified by the governing procedure. Unlike a thermocouple, which measures temperature at a local point, the resistance method reflects the average temperature of the winding.
Multi-channel systems measure resistance and thermocouple temperature during transformer heating programs. Low-resistance instruments are used for transformer windings, coils, shunts, conductors, and electrical joints that require four-wire Kelvin measurement.
Important note: suitability depends on the required resistance range, channel count, connection method, test setup, and governing procedure.
HOT-30 Hot Winding Resistance Measurement System
The HOT-30 is a multi-channel hot winding resistance measurement system for acquiring resistance and thermocouple measurements from multiple transformer windings during temperature-rise evaluations.
Product Details
- Up to 8 resistance reading channels
- Four-wire measurement method
- Up to 12 temperature reading channels
- Uses 24 AWG Type K thermocouples
- Designed for transformer winding-resistance temperature testing
- Supports measurement of multiple transformer windings
Included accessories: 8 Cat5e data cables, 8 isolation modules, 8 banana jack sets, 8 Kelvin probe sets, 12 Type K thermocouples (72 in.), and 1 USB Type A to Type B cable.
Application note: the HOT-30 is intended for transformer evaluations requiring resistance and thermocouple measurements from multiple points during a heating period.
4176 Programmable Digital Micro-Ohmmeter
The 4176 programmable digital micro-ohmmeter measures resistance from 1 µΩ to 30 kΩ using a four-wire Kelvin connection. It is intended for transformer windings, coils, shunts, wire, and other resistance-measurement applications.
Product Details
- Measurement range from 1 µΩ to 30 kΩ
- Basic accuracy of 0.04%
- Seven ranges, manual or auto-range
- Separate source and sense terminals for four-wire Kelvin measurement
- Accepts banana plugs, spade lugs, or wire connections
- Adjustable-intensity VFD display
- Remote operation through RS-232
- Optional USB interface available
Typical applications: transformer winding resistance measurement, coil testing, shunt measurement, wire resistance verification, and other electrical resistance measurements.
Resistance Measurement Instrument Comparison
| Model | Primary Use | Typical Application | Relevant Specifications |
|---|---|---|---|
| HOT-30 | Multi-channel hot winding resistance measurement | Multi-winding transformer evaluations using resistance and thermocouple measurements | Up to 8 resistance channels and 12 temperature channels |
| 4176 | Low-resistance measurement | Transformers, coils, shunts, wire, and conductors | 1 µΩ to 30 kΩ range with 0.04% basic accuracy |
Frequently Asked Questions
What is the HOT-30 used for?
The HOT-30 measures winding resistance and thermocouple temperature across multiple channels during transformer temperature-rise evaluations.
Why use the winding-resistance method instead of only thermocouples?
The winding-resistance method is used to calculate the average temperature of the winding, while a thermocouple typically measures temperature at one local point.
What does the 4176 micro-ohmmeter measure?
The 4176 measures resistance from 1 µΩ to 30 kΩ using a four-wire Kelvin connection. Typical applications include transformers, coils, shunts, wire, and other electrical resistance measurements.
Provide the resistance range, number of measurement points, temperature-input requirements, and test procedure.
Measurement Applications
- Transformer winding temperature determination
- Multi-winding resistance monitoring
- Resistance and thermocouple measurement during heating periods
- Motor, inductor, and coil resistance evaluation
- Resistance measurement of shunts and conductors
- Transformer and inductor winding resistance verification
- Electrical joint and connection resistance checks
- Resistance checks during production and fault investigation