Written-Pole® single-phase motors are the largest single-phase electric motors available in the market today. The application of Written-Pole® technology allows these revolutionary new motors to operate on existing single-phase distribution, eliminating the need for three-phase power. Their low starting current and energy efficient operation, combined with their simple robust construction, make Written-Pole® motors the preferred choice when compared to phase converters with three-phase motors.

Ranging in size from 15 to 60 horsepower, Written-Pole ® single-phase motors are ideal for a variety of applications including irrigation, grain drying, grain handling, aeration, rolling mills and oil production.

Advantages of Written-Pole® Single-Phase Motors

True Single-Phase Operation

Written-Pole® single-phase motors are true single-phase motors that do not require phase converters to operate on a single-phase service. The motor's capacitor start/run design is similar in concept to conventional single-phase motors, however the innovative use of Written-Pole® technology allow for dramatically reduced starting currents and increased operating efficiencies compared to conventional single-phase motors.

Low Starting Current

Written-Pole® single-phase motors exhibit starting current requirements comparable to conventional single-phase motors one-fourth their size. This feature reduces annoying voltage sags when starting without requiring users to install complex reduced voltage starters.

Their low starting current dramatically enhances the capability of a single-phase service to support much larger motors than previously thought possible, eliminating the need for costly three-phase service extensions.

Starting and Running Current Comparison
230 Volt Single-Phase

Conventional Single-Phase

Written-Pole® Single-Phase

Rating

FLA

LRA

Rating

FLA

LRA

5

22

150

20

68

130

7.5

28

220

30

100

185

10

39

288

40

130

245

15

70

377

60

200

360

FLA – Full Load Amps, LRA – Locked Rotor Amps

Energy Efficient, Unity Power Factor Operation

The technology used in Written-Pole® single-phase motors represents a significant leap forward in single-phase motor design. Their energy efficient, unity power factor operation reduce utility bills, while decreasing the electrical load on distribution wiring, transformers, and starting contactors.

Single-Phase Performance Comparison
230 Volt Single-Phase

 

Conventional

Written-Pole®

Comparison

Rating (hp)

15 Hp

30 Hp

100% higher

Full Load Amps (line)

70

100

43% higher

Locked Rotor Amps (line)

377

185

51% less

Efficiency (%)

82.0%

94.1%

15% higher

Power Factor

0.86

Unity

16% higher

Input Power (kW)

13.6 kW

23.8 kW

75% higher

Input Demand (kVA)

16.1 kVA

23.8 kVA

48% higher

Written-Pole® single-phase motors increase the available horsepower for single-phase applications without a corresponding increase in current and power requirements.

Three-Phase Performance using Single-Phase Power

While their low starting current and high operating efficiency eliminate the need for three-phase power in many applications, Written-Pole® single-phase motors also compare favorably to premium efficiency three-phase motors in many areas. In fact, Written- Pole® single-phase motors often go beyond three-phase performance, enhancing the system's performance by reducing starting current requirements to levels below that of three-phase motors and eliminating the need for reactive power through their unity power factor operation.

Three-Phase Performance Comparison
208 Volt Three-Phase, 230 Volt Single-Phase

 

Premium Efficiency Three-Phase

Written-Pole®
Single-Phase

Comparison

Rating (hp)

30 Hp

30 Hp

Equal

Full Load Amps (line)

75

100

33% higher

Locked Rotor Amps (line)

473

185

61% less

Efficiency (%)

94.1

94.1

Equal

Power Factor

0.84

Unity

19% higher

Input Power (kW)

23.8 kW

23.8 kW

Equal

Input Demand (kVA)

27.0 kVA

23.8 kVA

11.9% less

Note: Equivalent line current for a 208 volt three-phase Written-Pole motor would be approximately 66 amps.

A Written-Pole ® single-phase motor's lower starting current and unity power factor operation provide real-world benefits even when compared to premium efficiency three-phase motors.

Simple Robust Construction

Written-Pole® motors are constructed with materials and manufacturing methods similar to those used in premium efficiency three-phase motors. These time-proven practices ensure that Written-Pole ® single-phase motors are designed to operate reliably for many years.

The simple design also allows for field servicing of capacitors and capacitor switching without dismantling the motor, reducing downtime and cost of service.

Pre-Packaged Controls

All Written-Pole ® single-phase motors are supplied with the controls required for starting and operating, including the starting contactor, overload protection, start/run capacitors, capacitor switching, etc. This ensures that the controls are sized and installed correctly further enhancing performance and reliability.

Written-Pole® is a registered trademark of Precise Power Corporation