VARIABLE SPEED DRIVES (VSD) & SOFT STARTERS
1. Variable Speed Drives (VSDs)(Also known as: VFDs – Variable Frequency Drives, or AC Drives)
Raise and Lower supplies and installs Variable Speed Drives and soft starters to control motor speed and protect against electrical surges.
Purpose:
To control the speed and torque of an electric motor by varying the frequency and voltage of the power supplied to the motor.
How It Works:
- Converts incoming AC power to DC.
- Then inverts DC back to controlled AC with variable frequency/voltage.
- The frequency determines motor speed.
Main Features:
- Full control over motor speed.
- Allows energy savings at reduced speeds.
- Can provide torque boost at startup.
Typical Applications:
- HVAC fans and pumps
- Conveyors
- Elevators
- Mixers
- Any application requiring variable speed control
Advantages:
- Energy-efficient (especially for variable load applications)
- Precise motor control
- Reduced mechanical stress during start/stop
- Can reverse motor direction electronically
2. Soft Starters
Purpose:
To gradually start and/or stop an electric motor by controlling the voltage ramp-up (not speed control).
How It Works:
- Uses thyristors or similar semiconductors to slowly increase the voltage to the motor during startup.
- Motor reaches full speed at full voltage.
- Main Features:
- Soft start/stop
- Limited to full-speed operation
- Reduces inrush current and mechanical shock
Typical Applications:
- Pumps
- Compressors
- Fans (when speed control isn’t critical)
- Conveyor belts (simple start/stop control)
Advantages:
- Simple and cost-effective
- Reduces mechanical wear and tear
- Smaller size and easier installation
Improves power quality during startup
| Feature | Variable Speed Drive (VSD) | Soft Starter |
|---|---|---|
| Speed Control | Yes | No |
| Startup Current Reduction | Yes | Yes |
| Energy Savings | Significant (var. load) | Minimal |
| Motor Protection | Advanced Features | Basic |
| Complexity | High | Low |
| Cost | $$$ (Higher) | $ (Lower) |
| Application Type | Continuous Speed Variation | Simple Start/Stop |
In Summary:
- Choose a VSD if you need variable speed, energy savings, or precise motor control.
- Choose a Soft Starter if you only need to reduce startup current and protect mechanical parts during startup/stop, but don't need speed control.
Ready to improve energy efficiency and extend the life of your equipment? Whether you need advanced motor speed control with a Variable Speed Drive or a cost-effective Soft Starter solution, Raise and Lower is here to help. Our expert team supplies and installs the right systems for your needs, ensuring reliability, performance, and long-term savings. Contact us today to discuss your requirements and discover how we can provide tailored solutions that keep your operations running smoothly.
