MI 7010C AccuLoss® Automatic Capacitance Bridge

Advanced metrology for capacitance, induction and reactor loss

The MI 7010C AccuLoss® is a fully automated, microprocessor-controlled capacitance bridge based on current comparator technology. Designed for laboratories operating at the highest level of electrical metrology, the instrument offers exceptional accuracy for capacitance, inductance, reactor loss, AC resistance and transformer applications.

With a wide ratio range, automatic self-balancing, a large touchscreen and extensive automation options, the 7010C is a versatile and future-proof solution for both low and extremely high voltages.

A versatile bridge for capacitance and inductance

The 7010C can perform both 2-wire and 3-wire capacitance measurements. Three-wire measurements are used with large capacitors to eliminate the influence of lead impedance. The instrument supports capacitance ratios up to 1000:1, with a standard capacitance range of 10 pF to 10,000 pF. For applications requiring higher ratios, the 7010C can be expanded with the MI 7020 Two-Stage Range Extender, which increases the total ratio range to 2,000,000:1. For inductance measurements, the 7010C displays both the reactance ratio and the absolute inductance value (from mH to hundreds of kH). The bridge automatically compensates for frequency changes, which is essential for large inductive loads.

Reactor loss and tan delta measurements

In Reactor Loss mode, the 7010C performs the same measurements as in inductance mode, but also calculates:

> Power factor (PF)
> Impedance (Z)
> Active power (P)
> Reactive power (Q)
> Apparent power (S)

The bridge displays all parameters in engineering notation and warns when the applied voltage reaches 90% of the nominal value of the standard capacitor. The Hold function allows a snapshot to be captured and saved via USB.

Ideal for high-voltage and transformer laboratories

The 7010C is suitable for a wide range of applications, including:

> Shunt reactor loss measurements
> Power and potential transformer calibration
> High-voltage capacitor calibration
> High-voltage dividers
> Corona loss measurements
> Dielectric and insulation testing
> Inductance measurements up to hundreds of henries

With optional CG series high-voltage capacitors (up to 800 kV), the 7010C can be used in HV laboratories for tan delta, inductance and loss measurements at very high voltages.

Automatic operation via touchscreen

The 7010C has a large, clear touchscreen that can be used to set all functions:

> Cx and Cs input
> Dissipation factor
> Number of measurements and statistics
> Frequency (50/60 Hz)
> Extender ratio
> Measurement windows and filters

The interface supports storage and loading of test configurations, automatic measurement sequences and direct USB export. All measurement data can be transferred to a PC via IEEE-488 for further analysis or archiving.

Current comparator technology for maximum accuracy

The 7010C utilises a two-stage compensated current comparator, minimising phase and amplitude errors. Automatic self-balancing makes the instrument particularly suitable for large inductive loads where frequency variations occur — a challenge for traditional manual bridges. Built-in lead compensation minimises the influence of cable length, which is essential for large capacitors and high-voltage setups.

Optional range extenders and accessories

The 7010C can be expanded with:

> 7020 Two-Stage Range Extender (2000:1 or 1000:1)
> 7200ACC Current Comparator for CT calibration
> 7201ACT electronically assisted CT
> CG series high-voltage capacitors (50–500 kV)
> Custom HV cable sets
> Shielded rack on wheels

These extensions make the system suitable for both laboratory and field applications.

Top-level technical performance

> Capacitance: 10 pF – 10,000,000 pF
> Ratios: 1:1 to 1000:1 (expandable to 2,000,000:1)
> Dissipation factor: 0–10%, resolution 1 ppm
> Inductance: 700 µH–700,000 H
> Test frequencies: 50 and 60 Hz
> Accuracy: < 15 ppm for all Cx ratios
> Tan delta: ±1% of measurement + 10 ppm
> Warm-up: < 5 minutes
> 7-inch touchscreen

A complete solution for capacitance and inductance metrology

The 7010C AccuLoss® offers a unique combination of accuracy, automation and versatility. By combining capacitance, inductance, reactor loss and high-voltage measurements in a single instrument, it provides a powerful and future-proof solution for laboratories working at the highest level of electrical metrology.