Digital multimeter with insulation resistance measurement BM887 TRMS VFD, T, Riso 50V-1000V 102166

Safety and Precision in One Device

Working with modern electrical installations, especially where variable frequency drives (VFD) are present or insulation testing is required, demands equipment that not only measures parameters but primarily protects the user and the installation itself. The BM887 multimeter is a tool designed for preventive and emergency diagnostics, combining the functions of an advanced True RMS meter with a powerful insulation resistance tester. Thanks to the use of low-pass filters (LPF), the device effectively filters out high-frequency interference typical of VFDs, enabling reliable voltage and frequency readings even in challenging environmental conditions.

Comprehensive Insulation and Network Diagnostics

A key advantage of this model is the ability to perform insulation tests at five different voltages: 50 V, 100 V, 250 V, 500 V, and 1000 V. This allows flexible adaptation of the test to the type of circuit being examined—from delicate electronics to heavy-duty industrial installations. The meter achieves an insulation resistance measurement range up to 25 GΩ, which is sufficient to detect even subtle insulation defects before they lead to serious failures. To facilitate field work, the LOCK-TEST function is included, which locks the measurement result after completion, eliminating the need to continuously hold the button during long continuity tests.

Furthermore, the device features a unique SMOOTH mode that stabilizes the display readings during insulation resistance measurements. This means the operator does not have to interpret fluctuating values on the screen—instead, they receive a stable result, significantly speeding up the assessment of the installation's technical condition. Additionally, the Beep-Jack™ function automatically detects incorrect probe connections to the input jacks and emits an audible warning. This simple solution significantly reduces the risk of meter damage by the user during quick replacement of test leads.

Ease of Operation and Work Safety

Performing measurements in complex electrical circuits requires not only precision but also confidence in safety. The BM887 meets rigorous safety standards: CAT III 1000V and CAT IV 600V, making it a safe tool for work on main distribution boards and industrial installations. The large, dual LCD display with backlight allows simultaneous reading of the numerical value (up to 6000 counts) and a dynamic bargraph (updated 40 times per second), which is invaluable when observing real-time value changes, such as during the search for short circuits or overloads.

The device is equipped with a range of features that facilitate daily work:

• Remote probe with button – enables continuity measurements or insulation tests without needing to hold the meter housing in hand (e.g., during installation in hard-to-reach locations).
• MAX/MIN mode – automatically records extreme values during the measurement, which is crucial when diagnosing momentary voltage drops or surges.
• Auto-ranging – the meter automatically selects the appropriate measurement range, saving the operator time.
• Temperature measurement – a range from -40°C to +537°C allows quick temperature checks of heating elements or motors without using an additional thermometer.

In practice, this means the ability to precisely read AC and DC voltage up to 1000 V, as well as current up to 20 A, utilizing True RMS technology for both types of current. Frequency measurement is supported by an LPF filter for VFDs (up to 440 Hz), and the capacitance range reaches 20 mF. The automatic lead resistance calibration function further increases accuracy in the resistance range by eliminating errors introduced by the test leads themselves. Thanks to the combination of robust construction and advanced software functions, the BM887 becomes a versatile tool for electricians seeking a single device for full diagnostics—from simple voltage measurements to complex insulation integrity tests in industrial systems.