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Yokogawa 2490 Power Series Plus Digital Switchboard Meter AC Amps/ AC Volts/ Frequency

  •  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
AC Amperes Measuring Capabilities Available Connection Single Phase
Maximum Input Rating 0-1 Amp AC
0-5 Amp AC
Electrical Legend Amps AC
Kiloamps AC
AC Voltage  Measuring Capabilities Available Connection Single Phase
Maximum Input Rating 0-150 Volt AC
0-300 Volt AC
Electrical Legend Volts AC
Kilovolts  AC
Frequency Measuring Capabilities Available Connection Single Phase
Maximum Input Rating 150 Volt AC
300 Volt AC
Electrical Legend Hertz
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 1 AMP AC 11      
5 AMP AC 15
150 Volts 21
300 Volts 25
Frequency - 150 V Rating 81
Frequency - 300 V Rating 83
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) Maximum scaling ratio for Amps is 5000:1 (25.00 kiloamps for 5A input).
2) Maximum scaling ratio for volts is 1250:1 (150 kilovolts for 120V input).
3) AHD suffix not available with Frequency Meter.
4) AFB and AHF suffix not available with Amp or Volt meters.
5) 120/240V Auxiliary power is standard with all 2491 models.
6) NIST Calibration Certificate: Specify and add $50.00 each per unit.
7) NIST Calibration Certificate with Test Data: Specify and add $100.00 each per unit.
8) Certificate of Conformance: No charge, but specify with order.
Example Product
  Base Model Max. Input Frequency Analog Output Communication
Dual Function Digital Switchboard
150 Volts
400 Hz
4 to 20 mA
2491 21 2 AHD 1
Ordering Information
Model Description Price
2491 Yokogawa 2490 Power Series Plus Digital Switchboard Meter;
AC Amps/ AC Volts/ Frequency
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