EMHEATER Variable Speed Drives (VSDs) deliver accurate control of electric motors by adjusting the frequency and voltage supplied to the motor. This allows motors to run only at the speed required for the application, resulting in significant energy savings and improved process control.
Clean Imports (part of TCGC) is the official sole distributor of EMHEATER products in Southern Africa.
Variable Speed Drives (VSDs)
What is a Variable Speed Drive (VSD)?
A Variable Speed Drive (VSD) converts fixed-frequency AC power into a variable-frequency AC supply. By controlling both frequency and voltage, the drive regulates motor speed, torque and power output with high precision.
Key advantages of speed control:
- Motors use only the energy needed for the process
- Reduced mechanical stress and longer equipment life
- Improved process accuracy (based on feedback such as flow, pressure or temperature)
EMHEATER products are technically Variable Frequency Drives (VFDs). In South Africa the term “Variable Speed Drive (VSD)” is most commonly used, so we use this naming convention.
Related reading:
EMHEATER VSD Range
3-Phase Input and Output
3-Phase (220V ±15%) Input
3-Phase (~220V) Output
3-Phase (380V ±15%) Input
3-Phase (~380V) Output
3-Phase (440~550V) Input
3-Phase (~480V) Output
3-Phase (440~550V) Input
3-Phase (~525V) Output
3-Phase (550~790V) Input
3-Phase (~690V) Output
Single-Phase to 3-Phase Converters
Voltage Boosting (Step-Up) Drives
1-Phase (220V ±15%) Input
3-Phase (~220V) Output
1-Phase (220V ±15%) Input
3-Phase (~380V) Output
T-Series (Vector Control Inverters)
For Synchronous (Permanent Magnet) Motors
3-Phase (220V ±15%) Input
3-Phase (~220V) Output
3-Phase (380V ±15%) Input
3-Phase (~380V) Output
Custom cabinet solutions (VSD + peripherals in one enclosure) are available on request.
Benefits of using a Variable Speed Drive
- Energy savings of 25–70% on pumps, fans and other variable-torque applications
- Controlled starting current and smooth acceleration
- Extended motor and equipment life
- Adjustable operating speed and torque
- Controlled stopping and reverse operation
- Reduced power-line disturbances
- Built-in protection against over/under voltage, phase loss and overload
- Power-factor correction and advanced control features (PID, multi-motor control, communication interfaces)
How Variable Speed Drives Work
A modern VSD consists of three main stages:
- Rectifier – Converts incoming AC to DC
- DC Link / Filter – Smooths the DC voltage
- Inverter – Converts DC back to variable-frequency AC using Pulse Width Modulation (PWM)
The higher the output frequency, the faster the motor runs. This allows precise control from near-zero speed up to and beyond the motor’s base speed.
Common Applications
VSDs are widely used in:
- Pumps and water supply systems
- Fans and HVAC
- Conveyors and material handling
- Steel, cement, sugar, paper, rubber, plastic and textile industries
- Machine tools and process control
- Agriculture and irrigation
ESKOM energy-saving fact sheets:
VSD vs Soft Starter
VSDs offer all the benefits of a Soft Starter plus continuous speed control. Choose a Soft Starter when only soft starting is required and initial cost is the main priority. Choose a VSD when process optimisation, energy savings or speed control is needed.
Peripherals for VSDs
Many installations benefit from additional peripherals to improve performance, protection and reliability. We supply a complete range of peripherals for EMHEATER VSDs, including:
- DC Bus / Link Chokes (Reactors)
- AC Input & Output Chokes (Reactors)
- EMC / EMI Filters
- Sine Wave Filters
- Dynamic Braking Units & Braking Resistors
Spare Parts & Accessories
Genuine EMHEATER spare parts and complementary accessories are available, including keypads, control cards, power cards, IGBT modules, fans, capacitors, reactors, filters and more.
Need a quotation or technical advice?
Contact us today – we supply end users and resellers nationwide with flexible partnership options.
