1 to 3 Phase Converters

SRABBEY-Unit_with-Man-copy2zDemand for three-phase power is growing much faster than the availability of three phase electrical service. Many agricultural, telecommunications, industrial and municipal applications are best powered by three phase equipment. However, in most rural and remote areas only single-phase service is available.The 1-to-3 Power Source Phase Coverter from Precise Power solves this problem. Using revolutionary Written-Pole® technology, the 1-to-3 Power Source Phase Coverter avoids the high fuel costs, high maintenance costs and pollution of fossile-fuel powered engines. It delivers power quality superior to that of conventional phase converters. And it’s far more cost effective than the extension of three-phase service for both utilities and their customers.

The 1-to-3 Power Source Phase Coverter is:

Cost effective
The 1-to-3™ avoids extending three-phase distribution where single-phase service already exists. Upgrading the line to three-phase typically costs $30,000 to $60,000 per mile.
Cost saving
A 1-to-3 Power Source Phase Coverter can avoid $12,000 to $60,000 per year in monthly fees for three-phase power. In addition the Written-Pole® motor driving the 1-to-3 Power Source Phase Coverter is highly efficient, resulting in a full load efficiency exceeding 84%. This can reduce energy costs by thousands of dollars, year after year. And since the utility delivers only unity power factor to the 1-to-3 Power Source Phase Coverter there is no power factor penalty charge. In some Areas this can provide significant additional savings.
Low maintenance
The 1-to-3 Power Source Phase Converter can be used effectively in place of internal combustion engines that are often used as prime movers for pumps or generator sets. The Written-Pole® motor requires very little maintenance compared to engines. Air and noise pollution is reduced and reliability is greatly improved.
Power quality improvements
The 1-to-3 Power Source Phase Coverter allows weak single-phase lines to deliver strong three-phase power with excellent voltage regulation and precise 60hz frequency. In addition the Written-Pole® motor will provide ride through for a momentary utility power interrupt of several seconds or less. The motor generator also isolates the application (and the utility) from harmonics that can be harmful to sensitive loads.
Low starting current
Written-Pole® motors start up on only about three times operating current or less. This eliminates excess voltage sag or “flicker” that can cause problems on distribution lines.

Written-Pole® Converter Supplies Quality Three-Phase Power to Remote Load; Meets Stringent Flicker Specification

ABSTRACT: A Written-Pole® PowerRide™ motor drives a 3-phase generator. The M-G set provides 3-phase power to drive any appropriate load, such as 3-phase electronics, industrial loads, or 3-phase motors. The generator portion is significantly over-sized to provide large starting current for conventional motors up to 50 HP and provides clean, well-balanced voltage sinewave output. The Written-Pole® motor improves power quality on the distribution line and supplies ride-through during voltage sags and blackouts caused by recloser operations. A “velvet start” design is also described in which the starting current of the motor is actually less than full load operation current. This results in very low flicker during start. A case study is presented showing avoided cost of $200,000 for 3-phase extension, as well as avoiding 3-phase availability charge of $15,000 per year.

INTRODUCTION: Written-Pole® motors change the magnetic poles on the rotor while the motor operates. They start with low starting current and then run synchronously. The first Written-Pole® motors were built “inside-out,” with the rotor outside of the stator. This was done to provide high inertia to ride through power interruptions. Low starting current does not overheat the motor windings, and high inertia loads start easily. These motors are called “external rotor” or PowerRide™ design.

This paper discusses a Remote 3-Phase Power Source. This is a single-phase Written-Pole® motor connected to a conventional 3-phase generator. One model uses a 60 HP ride-through motor driving a 180 kW (rated) generator. The over-size allows the generator to start and run a conventional 50 HP induction motor that has very high start current. For example, the 480 volt single-phase Written-Pole® motor operates at 100 amp fully loaded. There is a “velvet start” (option) that starts the machine at 80 amp. When the 480 volt, 50 horsepower, 3-phase motor load starts, it draws 800 amp per phase on all three phases, even while the distribution line sees only about 180 amp single-phase. During running, the utility only sees the unity power factor single-phase motor as a load, with complete isolation from any harmonics etc., from the customer load. Use of a ride-through Written-Pole® motor allows the customer load to continue operation for several seconds during interrupts on the utility (reclosers) and also isolates the customer load from voltage dips and transients. It is expected rural electric suppliers may use this power source to profitably provide 3-phase power to any customer with any 3-phase load within the Written-Pole® motor limits.