Model 928A Power System Multimeter

The Model 928A Power System Multimeter with Floating-Point DSP Digital Signal Analysis is an AC Power measurement instrument, providing outstanding performance and flexibility in a small, hand-held package. Not only does the Model 928A measure basic data and power quantities, but it also measures power quality including harmonics, flicker, sags, surges and interruptions. Incorporating a graphic LCD display, serial communications, real time clock and an unprecedented combination of features makes the Model 928A the ideal instrument for the power professional.

For current measurements, Model 928A works with several Arbiter external Current Transformers available as accessories to the unit.



Configuration Note The Arbiter Systems®, Inc. Model 928A Power System Multimeter has two identical measurement channels, Channel A and Channel B. Each input channel has a voltage input and a current input. Current inputs are intended for use with external CTs having a nominal output of 0 Arms to 1 Arms or 0 Vrms to 1 Vrms. For basic measurements (voltage, current, frequency, and phase angle) any combination of inputs may be used. For power and energy measurements (active power, apparent power, reactive power, and power factor), one voltage and one current must be selected.


Input Range 1 Vrms to 660 Vrms
Impedance 1.2 megohm, differential


Input Range 0.01 Arms to 1.2 Arms or 0.01 Vrms to 1.2 Vrms
Low Range to < 1 mA or 1 mV
Burden 0.01 ohm maximum (current input style) or 100 kohms nominal (voltage input style)


Voltage and Current

Method Wideband: True rms, 3 kHz Bandwidth
Narrowband: Fundamental magnitude
Accuracy 0.1 % of reading or ± 5 mV, whichever is greater (voltage)
0.1 % of reading + CT errors (current)
1 % of reading + CT errors (low current range)

Phase Angle

A-B Range 0 ° to 360 ° or ± 180 °
A-B Accuracy 0.1 °
Underrange < 1 ° typical


Range 50 Hz or 60 Hz ± 5 Hz
Accuracy 0.005 % of reading


Input Channel A and Channel B, simultaneous
Range 2nd to 50th Harmonic (50 Hz or 60 Hz fundamental)
Accuracy 0.1 % THD + 5 % reading
Display THD; K-factor; Amplitude bar graph; and individual harmonic magnitude and phase (simultaneous)

Waveform Display

Channel A and/or Channel B


Range 0 MVA or MVAh to 99999 MVA or MVAh
± 99999 MVAR or MVARh
± 99999 MW or MWh
± 1.0000 PF, lead or lag
Accuracy 0.1 % of VA, for VA, VAR, and W
0.001 PF



Display 128 pixel x 64 pixel graphic LCD
Keypad 30 key keypad
Serial USB
Memory 512 KB flash
Data User setups, Real Time Clock, Approximately 400 KB measurement data

Power Requirements

Internal Battery

Type 4-AA Cells, alkaline or NiMH (not included)
Operation 30 hours typical with alkaline cells. 60 hours typical with NiMH


Voltage + 7 Vdc, unregulated (not included)
Current < 100 mA
Connector 5.5 mm x 2.0 mm, center positive



Instrument/Size 200.0 mm x 104.2 mm x 37.4 mm (7.9 in x 4.1 in x 1.5 in)
381 mm x 305 mm x 299 mm (15 in x 12 in x 9 in), shipping
Weight 1 kg (2.2 lbs), net
2.5 kg (5.5 lbs), shipping


Temperature Operating: 0 °C to + 50 °C
Nonoperating: – 40 °C to + 75 °C
Humidity Noncondensing