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Dr. Robert Holcomb and team have designed and built these units in house. Overview Three different units were tested at the main HES location, in Sarasota, FL.
System A: 3 phase to 3 phase, delta, 208 VAC (40 kW)
System B: 3 phase to 3 phase, delta, 480 VAC
System C: Split phase to 3 phase, 208 VAC Additionally, a site visit to a building where a 15 kW 3 phase to 3 phase device was installed:
System D: 3 phase to 3 phase, delta, 208 VAC (15 kW)
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All these extracts make more sense with the photographs of the devices and wiring.
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System A System A (Figure 1) was examined on Tuesday, October 25, 2022. This device is a three phase to three phase converter. Three phase power was supplied by a diesel generator outside the building.
Note that in all of these devices are using the same configuration, where the input and output voltage taps are at the same connection points:
Two smaller gage wires per phase are hooked up to the system (total of six wires) to run the system in ‘normal’ mode. When these wires are disconnected, the system is said to be in ‘bypass’ mode. Voltage taps for the DENT Elite Pro XC Power Meter are shown below. The DENT power measurement unit uses the colors black=L1, red=L2, and blue=L3 for both voltage and current in its standard configuration as per the manual.
Comparison of clamp-on current measurement using an independent Mastech MS2115A meter and HES (Klein Tools CL800) showed some differences, but variations in the signal were seen in all meters due to the orientation of the meters. Given previous testing by other independent firms, it is unlikely measurement devices are suspect (Table 1).
With the system loaded in a standard HES configuration, with load, the clamp on meters showed respective input and output currents as shown in Table 2.
However, this is an AC, not DC system, so simple multiplication of currents and voltages cannot be done to calculate true power, due to the phase angle differences (power factor, PF = cosine(phase angle)) between voltage and current. This can be done at HES by two different methods, using the DENT instruments Elite Pro XC Power Meter, and the handheld PCE Instruments PCM1 (PCE PCM1). The DENT system uses current coils to measure AC current, but a minimum of approximately 5 Amps must be flowing for current to be measured. Measurements by the DENT data acquisition system, as originally configured showed power output exceeding power input (see Figure 4 and Figure 5); 4.1kW input and 7.9 kW output:
Temperatures of the core of the system were taken (Figure 6); temperatures rose from 24.9C to 26.4C in approximately 8 minutes. Cooling fans on external power were used to keep the system cool, but no large temperature excursions were found.
Moving the system did not show any change to the voltages and currents from the system.
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