Three-Phase Reactors for Motor Protection and Smooth Starting
Large motors are the backbone of industries – powering pumps, fans, compressors, conveyors, and more. But when they start, they can pull a huge surge of current, putting stress on both the motor and the electrical system. That’s where three-phase reactors come in.
What is a Three-Phase Reactor? A three-phase reactor is an inductive device with three windings – one for each phase of an AC power supply. It’s designed to control the flow of current, improve power quality, and protect equipment from electrical stress. In motor applications, it’s often called a motor starting reactor because of its role in limiting high inrush current when motors are switched on.
Why Motors Need a Reactor During Startup When a large motor starts, it can draw 6 to 8 times its normal running current. This can cause: Voltage dips in the network (lights flickering, other equipment slowing down)
Excessive heat and mechanical stress on the motor windings Higher risk of tripping breakers or damaging the power supply A three-phase motor starting reactor acts like a cushion – it temporarily reduces the current flow, allowing the motor to start gently. Once the motor reaches around 80–90% of its speed, the reactor is bypassed, and the motor runs at full voltage.
Applications – Motors That Commonly Use Starting Reactors Three-phase motor starting reactors are used with large three-phase induction motors and synchronous motors in: 1. 2. 3. 4. 5. 6.
Pumps – Water treatment plants, oil refineries, and irrigation. Fans & Blowers – Cooling towers, ventilation systems, and industrial air handling. Compressors – Refrigeration, air compression, and process plants. Cranes & Hoists – Port cranes, gantry cranes, and heavy lifts. Marine Propulsion – Ship thrusters and propulsion motors. Mining Equipment – Crushers, mills, and conveyor drives.
Typical kVA Range Motor starting reactors can range from 15 kVA for smaller industrial motors to 2,000+ kVA for large plants, marine systems, and heavy industries.
Benefits of Using Three-Phase Reactors for Motors
Reduced Current Surge – Protects motors and wiring. Improved Power Quality – Prevents voltage dips in the network. Extended Motor Life – Less mechanical and thermal stress. Cost-Effective – A simple, reliable alternative to soft starters for certain applications. Low Maintenance – No complex electronics to fail.
Why Choose Miracle Electronic Devices Pvt. Ltd. At Miracle, we’ve been manufacturing transformers, reactors, and inductors for over 30 years, supplying to industrial, marine, medical, and renewable sectors worldwide.
ISO-certified facilities
Custom designs for voltage, kVA, and environment requirements Proven track record in exports to the US, Europe, and Asia-Pacific Engineering expertise for reliable, high-performance power solutions Whether you need a standard three-phase reactor or a custom-built motor starting reactor, we deliver performance, durability, and global quality standards. Contact us today to discuss your motor starting and power quality requirements. Read more: Three-Phase Reactors for Motor Protection and Smooth Starting
