Power Series

Digital Switchboard Meters


  • 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. This is a desirable feature when distorted waveforms are present on the line. High resolution/high intensity LED displays can be viewed from almost any angle.


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 32 meters 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.

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 per the connection drawings for the model selected.

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Model 2493:

The 2493 triple display multi-function power meter is designed for easy retrofits into existing switchboard meter panel cutouts. The 2493 features three easy-to-read LED displays, minimum/maximum values at the touch of a button, scaling up to 1250:1 for potential transformers and 5000:1 for current transformers. Optional 0-1mA DC and 4-20mA DC analog outputs are configurable by the user and RS485 communications option is available at no additional cost. The 2493 is also available with a wide choice of power supply options.

  • Literature
  • Specifications
Literature and Technical Information
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Panel Instrumentation

++ Power Series | Models 2491, 2492, 2493
Model 2491: 1 display, 1-3 functions – Select to display
Model 2492: 2 displays, dual function
Model 2493: 3 displays, Triple function
Model 2491, 2492: 4 1/2 digit red, 0.56″ high LEDs
Model 2943: 4 digit red LED (9999 counts) - 0.56″ high LEDs
Display Color: Red
Response time:
2491, 2492: 200ms min. update time for 2491, 2492
2493: 160ms min. update time for V/V/V, A/A/A, Watt/VAR/PF
320ms min. update time for V/A/Hz
Auxulliary power
2491: 120V or 240V AC (±15%), 45-65 Hz, 4.5VA max.
2492: 120V or 240V AC (±15%), 45-65Hz, 4.5VA max.
2493: 120 or 240V AC (±15%), 45-65 Hz, power consumption 10VA max. with Optional 24, 48, 125 VDC Power supplies
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: 50/60Hz and 400Hz
Input Range:
Rated current: A/W/VAR: 0-200%; PF/PA : 20-200%
Rated voltage: V/W/Var: 120%; FPA: 50-120%; Frequency:20-120%
Input Frequency Rate
Volts, Amps, Hertz: 45-65Hz up to the 9th harmonic measuring capability2% 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% continous; PF/PA: 150% continous
Rated current: <0.2 VA per element
Rated voltage: 120V; <0.2 VA per element, 240V; <0.4 VA per element
Accuracy: Reference condition: 25°C, 45-74%RH, at rated input 60Hz sine wave, 30 min. warmup
Voltage:Current:Watt/VAR: ± 0.2% of reading ± 0.1% of full scale
Power Factor ±0.05 Power factor
Phase Angle: ±0.5° Phase Angle
Frequency: ±0.01 Hz @ 40-70Hz, 0.1Hz @ 300-500 Hz
Analog Output
0 to 1mA,0 to ± 1mA: 10VDC compliance into 10k ohm load maximum
4 to 20mA,12 ± 8mA: 15VDC compliance into 750 ohm maximum
Rated voltage: 120V; <0.2 VA per element, 240V; <0.4 VA per element
Response Time: 1 second maximum response time within ±i% of final value
Insulation voltage and resistance:
Input to output/case: 2500V AC for 1 minute / more than 10 Megohm @ 500V DC
Aux. power to case: AC: 2000V AC for 1 minute / more than 10 Megohm @ 500V DC and DC: 500V DC minimum / 10 Megohm minimum @ 100V DC
Aux. power to output: AC: 2000V AC for 1 minute / more than 10 Megohm @ 500V DC and Resistance DC: 500V DC minimum / 10 Megohm minimum @ 100V DC
Output of case: 1000VAC for 1 min./ more than 10 Megohm @ 500VDC
Temperature Range
Operating Temp.: -20 to +60°C at 90% RH maximum (non-condensing)
Storage Temp: -40 to 85 °C
Temp. Coeff.:
Display and Comm: ±150 PPM/°C maximum of full scale
Analog Output: ±250 PPM/°C maximum of full scale
Dimensions: W x D x H = 4.33 x 6.54 x 4.33 inches
2491 1000g (2.2 lbs)
2492 1100G (2.4 lbs)
2493 1250G (2.75 lbs)