Yokogawa 2490 Power Series Plus Digital Switchboard Meter Power Factor and Phase Angle

  •  Scaling of the instrument for PT (potential transformer) primary ratings up to 1250:1; and CT (current transformer) primary ratings up to 5000:1.
  • Adjustable transducer output proportionate to the primary input setting.
  • Electrical legends (i.e., Watts, Kilowatts, Megawatts) can be set by the user and indicated by a red LED adjacent to the selected legend.
  • Display average setting: Adjustable to obtain a “rolling average” of inputs. Increasing the number of samples reduces annoying “digit bounce” by the least significant digit.
  • All settings are stored in non-volatile memory. If there is a loss of power to the instrument, all settings will remain as they were prior to power loss.
  • Accuracy of ±0.2% of reading, ±0.1% of full scale.
  • True RMS current and voltage measuring capability. A most desirable feature when distorted wave forms are present on the line.
  • High resolution/ high intensity LED displays that can be viewed from almost any angle.

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The POWER SERIES Plus digital switchboard meter was developed by Yokogawa Corporation of America to provide our customers with a versatile AC digital power meter. The heart of our POWER SERIES Plus meter is a programmable ASIC Power Measurement Chip (PMC) which was jointly developed by the General Electric Company and Yokogawa Electric Corporation. This unique PMC capability will continue to expand into many new power measurement and control products offered by Yokogawa Corporation of America.

The design of the POWER SERIES Plus combines a high accuracy digital switchboard meter with transducer output which can be configured in the field by an end-user, or when installed in new electrical equipment by an OEM. It eliminates requirements for a large inventory of dedicated instruments, and provides flexibility when new panel designs or system upgrades require changes in instrument transformer ratings. Our rugged metal case fits standard panel cutouts for switchboard meters and makes it a perfect replacement for less versatile instruments. The RS-485 communications option allows up to 32meters to be networked together for remote monitoring and control. In addition, the POWER SERIES Plus can be set up and locked out for security via the remote communications option.

Up to Three Screen
Ideally designed for easy retrofit into existing switchboard meter panel cutouts.
The 2491 has only one, easy to screen LED screen, while the 2492 features two different LED screens, to aid the user in comparing two different frequencies.

Highly Customizable
The POWER SERIES Plus can be configured for primary and secondary transformer inputs, legends, outputs and averaging function. At Yokogawa, we program each model according to the specified options required by the user. This minimizes the number of steps to set up the instrument at the job site or on the factory floor.

Each model is programmed only for the options selected, so there are no unnecessary menu items. If you select a Voltmeter without analog output, then set up will be limited to PT ratios, LED display, and average setting. All can be accomplished in less than one minute. If no transformer is required, the ratio entered for PT P and PT S is 1 (1:1).

Sturdy Construction
The POWER SERIES Plus is enclosed in a rugged steel case treated with zinc chromate to resist corrosion. The cover assembly and faceplate are constructed of high temperature polycarbonate material and have several gaskets which seal out dust and moisture from the front cover. The 26 position terminal board is a glass-filled polycarbonate material with #8 nickel-plated brass terminals inserted.

Power Series Plus - General Specifications
Power Factor Measuring Capabilities Available Connection 1P2W
3P4W (2 1/2 Element)
3P4W (3 Element)
Maximum Input Rating 120V AC 1 Amp
240V AC 1 Amp
120V AC 5 Amp
240V AC 5 Amp
Electrical Legend Power Factor
Power Angle Measuring Capabilities Available Connection 1P2W
3P4W (2 1/2 Element)
3P4W (3 Element)
Maximum Input Rating 120V AC 1 Amp
240V AC 1 Amp
120V AC 5 Amp
240V AC 5 Amp
Electrical Legend Power Angle
Display Type 4 digit red LED (9999 counts)
Response Time 200ms min. update time
Input Rating Current 0 to 1A AC; 0 to 5A AC
Voltage 0-120V AC, 0-240V AC (W/VAR/PF/PA)
0-150V AC, 0-300V AC (Volt/Freq)
Frequency 50/60 Hz and 400 Hz
Input Range Rated Current A/W/VAR: 0-200%; PF/PA : 20-200%
Rated Voltage V/W/VAR: 0-120%; PF/PA: 50-120%; Frequency: 20-120%
Input Frequency Range Volts, Amps, Hertz 45-65Hz up to the 9th harmonic measuring capability
±2% of Specified Accuracy
Sustained Input Rated Current A/W/VAR/PF/PA: 200% continuous; 10x rating for 5 seconds
Rated Voltage V/W/VAR/FREQ : 120% continuous; PF/PA : 150% continuous
Accuracy Reference condition: 25°C, 45-74%RH, at rated input 60Hz sine wave, 30 min. warm-up Voltage ±0.2% of reading ±0.1% of full scale
Frequency ±0.01 Hz @ 40-70Hz, ±0.1Hz @ 300-500 Hz
Analog Output and Response Time 0 to 1mA, 0 to ±1mA 10VDC compliance into 10k ohm load maximum
4 to 20mA, 12 ±8mA 15VDC compliance into 750 ohm maximum
1 second maximum response time within ±1% of final value
Temperature Coefficient Display and Comm: ±150 PPM/°C maximum of full scale
Analog Output ±250 PPM/°C maximum of full scale
Influence of Input Voltage <0.05 Power Factor (10-120% of rated voltage)
Input Frequency <0.05 Power Factor (45-65Hz)
Load Resistance (Analog Input) 0 to 1mA, 0 to ±1mA : 0 - 10K ohm within ±0.05% of full scale
4 to 20mA, 12 ±8mA : 0-750 ohm within ±0.05% of full scale
Dimension W x D x H = 4.33 x 6.54 x 4.33 inches
How to Order

2491 Single Phase Digital Switchboard

# -# -# -# -#
Maximum Input Rating Power Factor 1P2W 71        
Power Factor 1P3W 72
Power Factor 3P3W 73
Power Factor 3P4W (2 1/2 Elements) 74
Power Factor 3P4W (3 Elements) 75
Power Angle 1P2W 91
Power Angle 1P3W 92
Power Angle 3P3W 93
Power Angle 3P4W (2 1/2 Elements) 94
Power Angle 3P4W (3 Elements) 95
AC Input Rating 120 Volt/1 Amp 11
120 Volt/5 Amp 15
240 Volt/1 Amp 21
240 Volt/5 Amp 25
Frequency 50/60 Hz 1
400 Hz 2
Analog Output
No Output AAA
0 to 1 mA AFA
0 to ± 1 mA AFB
4 to 20 mA AHD
12 ± 8 mA AHF
Communication None 0
RS-485 1
Notes 1)  These models have a 3 1/2 Digit Display
2) 120/240V Auxiliary power is standard with all 2491 models.
3) NIST Calibration Certificate: Specify and add $50.00 each per unit.
4) NIST Calibration Certificate with Test Data: Specify and add $100.00 each per unit.
5) Certificate of Conformance: No charge, but specify with order.
Example Product
  Base Model Max. Input AC Input Rating Frequency Analog Output Communication
Single Phase Digital Switchboard
Power Angle 1P2W
120 Volt/5 Amp
400 Hz
4 to 20 mA
2491 91 15 2 AHD 1
Ordering Information
Model Description Price
2491 Yokogawa 2490 Power Series Plus Digital Switchboard Meter;
Power Factor and Phase Angle
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