- Resources & Support
- Powering Good
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 allow for dramatically reduced starting currents and increased operating efficiencies compared to conventional single-phase motors.
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.
|Description||Written-Pole® Single-Phase||Conventional Three-Phase||Conventional Diesel|
|Rated Output (hp)||75||75||75 (pump hp)|
|Rated Input Voltage||480||480||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.|
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, 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®|
|Full Load Amps (line)||75||100||33% higher|
|Locked Rotor Amps (line)||473||185||61% less|
|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.