Written-Pole® Motor Advantages
True Single-Phase Operation
BELLE™ 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 BELLE™ Written-Pole® technology allows for dramatically reduced starting currents and increased operating efficiencies compared to conventional single-phase motors.
Low Starting Current
BELLE™ 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
| Description | Written-Pole® Single-Phase | Conventional Three-Phase | Conventional Diesel |
|---|---|---|---|
| Rated Output (hp) | 75 | 75 | 75 (pump hp) |
| Rated Input Voltage | 460 | 460 | NA |
| Full Load Speed (rpm) | 1800 | 1775 | NA |
| Full Load Current (amps) | 116 | 83 | NA |
| Peak Starting Current (amps) | 220 | 430-575 | NA |
| Operating Efficiency (%) | 94.5 | 94.5 | 25.0% |
| Power Factor (pf) | Near Unity | 0.85 | NA |
| Input Power (kW at Rated Output) | 59.2 | 59.2 | 179 kW |
| Input Demand (kVA at Rated Output) | 59.2 | 67.7 | NA |
| Starting Demand (kVA) | 101 | 365-420 kVA | NA |
| Hourly Operating Cost | $6.55 per hour ($0.11 per kWh) | $6.55 per hour ($0.11 per kWh) | $11.26 per hour ($2.60 per gallon) |
| Monthly Demand Charges | Peak kVa demand is lower for Written-Pole® single-phase motors than comparable three-phase motors resulting in lower demand bills where applicable. | ||
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, BELLE™ Written-Pole ® single-phase motors also compare favorably to premium efficiency three-phase motors in many areas. In fact, BELLE™ 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 | 30 | 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 BELLE™ Written-Pole® single-phase motor's lower starting current and unity power factor provide real-world benefits even when compared to premium efficiency three-phase motors.
Download BELLE v. Diesel Comparison
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