VMX-PFE-04 Soft starter 3 kW, 230-460 V, series PFE, Motortronics

Motortronics PFE — Compact Soft Starters with Built-in Bypass

Motortronics PFE (engineered based on Fairford Electronics technology) is a range of ultra-compact soft starters for three-phase asynchronous motors rated from 2.2 to 22 kW (nominal current from 5 to 41 A). The primary highlight of this lineup is the built-in bypass contactor, which saves significant enclosure space and reduces heat dissipation during operation. We highly recommend this series for water supply pumps, HVAC fans, and light-duty conveyors where preventing water hammer and starting current overloads is critical under tight budget constraints.

Key Applications for Motortronics PFE Series

• Industrial and Domestic Pumps: Smooth acceleration eliminates destructive water hammer in pipe networks, while controlled deceleration avoids abrupt check valve closures.
• Fans and Exhausters: Lowering starting torque prevents belt slippage and premature wear on ventilation system bearings.
• Light-duty Conveyors and Belts: Soft starting eliminates jerks, preserving the integrity of transported goods and protecting mechanical gearboxes from wear.

Motortronics PFE vs. Competitors

Thanks to the proprietary 3-phase ramp control (3S technology), Motortronics PFE maintains a balanced magnetic field in motor windings during starting compared to 2-phase alternatives like ABB PSR. This minimizes winding heating and starting vibrations.

When Motortronics PFE is NOT Suitable

• Heavy-duty Starts with High Inertia: For crushers, centrifuges, or industrial mills, the thermal capacity of the compact PFE enclosure may be insufficient. In such cases, we recommend using variable frequency drives like Veichi AC310.
• Speed Control Requirement: If you need to regulate motor speed during operation, a soft starter won't work—please browse our general variable frequency drives section.
• More than 10 Starts/Hour without a Fan: With standard passive cooling, the unit might trigger thermal protection during frequent start-stop cycles. To increase starts up to 60/hour, always order the optional cooling fan VMX-PFEFAN01.

Our Engineering Insights on Motortronics PFE

• Simple Commissioning: These units do not require programming or navigating complex digital menus. Simply use a screwdriver to set the initial voltage (Start Level), ramp-up time (Acceleration), and ramp-down time (Deceleration) — it takes under 2 minutes.
• Compact Panel Space: The 45 mm frame width matches standard contactors or circuit breakers, making it extremely easy to mount side-by-side on a DIN rail, saving enclosure costs.
• Control Voltage Requirement: Please note that the internal control board requires an external 24 VDC power supply. If your panel only has 220 VAC, order the compatible VMX-PFE-035 power supply.