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Will the standard Zig-Zag connection shown in the Acme General Catalog serve as an I-Trap™?

No. The I-Trap™ is specifically designed to reduce high neutral currents.

To eliminate the problem of overheated neutral conductors, why not increase the size of the neutral?

First, increasing the neutral size does not eliminate the harmonic problem – they are still present in the system and may cause transformer overheating and possibly failure.

Second, installation of a new neutral conductor in long runs may be difficult and cost prohibitive when compared to the cost of installing an I-Trap™ unit.

What advantage does the I-Trap™ have over harmonic filters?

Harmonic filters must be matched to their load and they may cause a leading power factor, which, when tuned to a specific frequency, can actually aggravate the harmonic problem.

Will the I-Trap™ increase fault currents in my system?

The I-Trap™ will not increase three phase or phase-to-phase fault currents but can increase the available fault current on line to ground faults.

Will the I-Trap™ reduce phase amps?

Phase amps have been reduced by 18% in Acme laboratory tests. Depending on the conditions for a particular electrical system, the percentage will vary.

Will the I-Trap™ reduce neutral to ground voltages?

Yes. Lab tests have shown significant reductions.

Is the I-Trap™ for use on 480/277V systems?

It is for use on 208Y/120V systems only. For other voltages, contact the factory.

Where should the I-Trap™ be installed in the system?

It is recommended that the I-Trap™ be installed as close as possible to the harmonic producing loads on the three phase system. This location would typically be on the line side of a distribution panel that feeds the harmonic producing equipment.

How do I select the correct I-Trap™ for my system?

A measurement of current flowing in the neutral conductor from the load to the supply transformer will need to be taken with an RMS meter.

What causes a neutral current to flow in a balanced three phase system?

The vector addition of three phase fundamental currents will add to zero on a balanced system without harmonics. However, if triplen* harmonic currents are present, they will add in the neutral.
With high concentrations of non-linear loads, the neutral current can be as high as two times the line current.

* Harmonics which are odd multiples of three (3rd, 9th, 15th, 21st, etc.). Odd triplen harmonics add together in the neutral conductor