Integrated Soft Start – How it came about, why it is so great, and why everyone is talking about it.

We thought we’d take a moment to talk about American Rotary’s integrated soft start. For years, phase converters have had a reputation of drawing a huge inrush current upon start up. This disproportionate power draw has resulted in, among other things, dimming the neighbor’s lights, demand charges from the utility, and large increases on power bills. The engineering team took this age-old problem by the horns and set out to find a solution.

After investigating various forms of “soft starting” a motor (most of which are inefficient and/or delicate, not to mention very expensive), the lead engineer and co-founder, David Rehm, took it to a new level all together. His original idea was to make the soft start feature solid state (so that no failure of moving parts would ever occur), and to keep the cost down enough that everyone could afford this feature. The team set up meetings with the engineering department at Baldor Electric. After a year of design and development, we were ready to begin the testing phase of the new generator. What resulted surprised us all!

The new generator design achieved an 83% reduction in inrush (starting) current – and was granted a soft start rating. What’s more, is that American Rotary’s soft start phase converters deliver all the power required for hard starting, heavy duty applications, along with balanced pure sine wave output and power factor correction (I’ll address these features in another entry) for CNC and other voltage sensitive applications. This motor-integrated solid state soft start design is proprietary and exclusive to the Baldor/GENTEC American Rotary phase converter generator. It is affordable, reliable, made in the USA, and no one else has it.

Our marketing department launched the new Baldor/GENTEC phase converter with gusto! And the product is everything we hoped it would be. Then, as days and weeks went by, we started seeing the phrase “soft start phase converter” popping up in all sorts of places… Unfortunately, many phase converter manufacturers now claim that they too have soft start when indeed they do not. Many phase converter manufacturers use a regular stock motor by rewiring it for low voltage and cutting off the exposed rotating shaft (consequently, most of these companies are uninsured since the remnant of the shaft is a huge safety hazard). A regular stock motor is going to take the values of capacitance (in microfarads) shown here:

3HP: 240-360
5HP: 300-600
7.5HP: 600-900
10HP: 800-1200
15HP: 900-1800
20HP: 1600-2400
30HP: 2400-3000
40HP: 3200-4000
50HP: 4000-5000

Therefore, one way to verify a claim of “Soft Start” is to check the starting capacitance of the phase converter (How many microfarads are used in the starting circuit – or – how many capacitors and at what values are used?). If the microfarads fall within the values above, it is simply a stock motor and is not using integrated soft start.

American Rotary’s Soft-Start phase converter generator uses anywhere from 1/3 to 1/6 of the capacitance needed to start a stock motor. This also reduces inrush current by the same amount, which virtually eliminates demand charges from the utility and dimming the neighbor’s lights.

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