WattNode

The WattNode^® watt-hour transducer is used to measure electrical energy. The WattNode outputs pulses at a rate proportional to the watt-hours of energy flowing in the circuit being measured. The WattNode works with "safe" and easy to install split core current transformers (CTs).

The watt-hour pulses are counted by a Pulse Adapter connected to a Smart Sensor port on the Energy Logger Pro. When the pulse data is retrieved from the logger it is converted to kWh and kW measurements, which can be plotted, analyzed, and exported to Excel and other applications.

The WattNode is the smallest kWh transducer currently available. It is commonly installed inside an existing electrical panel which avoids the trouble and cost of installing a sub-panel. The screw terminal blocks unplug, making wiring fast and easy. The pulse output is optically isolated, so it can be connected to a Pulse Adapter and logger without any safety concerns.

The WattNode measures True RMS power with an accuracy 0.5% even with leading or lagging power factors, chopped or distorted waveforms, and high harmonic content. This makes the WattNode idea for monitoring motors controlled by variable speed drives. To assure reliability and accuracy, each WattNode is tested and calibrated using an automated NIST traceable calibration system. Long-term accuracy is assured by the use of fixed, precision resistors, not potentiometers.

For more detailed information, download the PDF of the WattNode Spec Sheet and Users Guide.

Four WattNode models are available from stock. Other models for 400 and 600 Vac electrical systems can be special ordered. Consult the WattNode User's Guide for information on how to select the correct WattNode model for your application.

WattNode models are available for use on single-phase, three-phase wye, and three-phase delta electrical systems with voltage ratings from 120 to 600 VAC. Current transformer available from 5 amps to over 1500 amps. There is a WattNode and CT combination available to measure virtually any electrical load.

The full scale measurement range of a WattNode depends on the model and current rating of the CTs. CTs are available in several styles, opening sizes, and many different full-scale current ranges. For maximum measurement resolution use a CT with a full scale current rating that matches or is slightly larger then the load current. Refer to the Current Transformer page for complete details.

Some Points To Remember:

WattNode's use 2 or 3 CTs and all the CTs must be the same current rating.
Delta models have 2 CT inputs and are typically use to measure single and 3 phase motor loads at a location remote from an electrical panel where there is no neutral wire.
Wye models have 3 CT inputs and are used to measure single and 3 phase motor, lighting, whole building loads at a location, typically in an electrical panel, where there is a neutral wire.
WattNodes and CTs have a 130% over range capability.

For assistance in selecting a WattNode model for your application please call 800-450-4454 or email us at sales@datalogger.com