Motor Power vs Starting Method
Selecting the Best Starting Method for Your Motor
Electric motors require a suitable starting method to ensure reliable operation and prevent excessive electrical or mechanical stress.
The correct starting method often depends on the motor power and the characteristics of the driven equipment.
Small Motors (Typically below 5.5 kW)
Smaller motors can usually start direct-on-line (DOL) without causing unacceptable current surges.
Common Methods
- Direct-on-line starter
- Simple contactor control
Typical Applications
- Small pumps
- Fans
- Small machinery
Medium Motors (5.5 kW – 75 kW)
As motor size increases, starting current becomes more significant. Controlled starting methods are often required.
Recommended Methods
- Soft starter
- Variable frequency drive
These systems reduce starting current and mechanical stress on equipment.
Typical Applications
- Industrial pumps
- Conveyor systems
- Compressors
- Large fans
Large Motors (Above 75 kW)
Large motors require more advanced starting methods to manage electrical demand and protect mechanical systems.
Common Solutions
- Soft starter systems
- Variable frequency drives
- Reduced voltage starters
These systems help prevent voltage dips and reduce mechanical shock during startup.
Other Factors Affecting Starting Method
Motor power is not the only consideration when selecting a starting method.
Other important factors include:
- Supply network capacity
- Mechanical load characteristics
- Required speed control
- Energy efficiency goals
- Process automation requirements
Expert Motor Control Solutions
Motor Control Scotland designs and supplies motor control systems for a wide range of industrial applications, from simple starters to fully integrated automation systems.
Our product range includes:
- SoftStart Core, +Safe, and Smart Series
- DrivePanel Core, +Safe, and Smart Series
- Custom PLC, HMI, and SCADA integrated systems
If you need assistance selecting the correct starting method for your motor, our engineers can help specify the most suitable solution.