- Vibration Monitoring
- PLC & I/O Cards
- Industrial Communications
- Automation Accessories
- Controllers & Data Acquisition
- AC Drives
- Isolator & Barrier
- Industrial Computers
- Encoders
- Safety Switches & Guard Locking
- Automation Software
- HMI Displays
- Motor Soft Starters
- Servo Drives
- CCTV & Security
- Robotics
- Pneumatic Cylinders
- Machine Vision
Motor Soft Starters
A motor soft starter reduces the voltage applied to a three-phase motor during starting and stopping, which limits inrush current and mechanical shock on the driven machine. Seven Star LLC supplies soft starters in Oman, with Schneider Electric Altistart 22, Altistart 48 and Altistart 480 units, the ABB PSR compact soft starter, soft starters from Danfoss (VLT MCD 600), Carlo Gavazzi and Lovato, and an Allen-Bradley motor controller currently listed, together with the Schneider Electric TeSys Track condition monitoring system. This is a small range, and other frame sizes can be sourced on request.
Read more about Motor Soft Starters 
Category guide
About Motor Soft Starters
A motor soft starter reduces the voltage applied to a three-phase motor during starting and stopping, which limits inrush current and mechanical shock on the driven machine. Seven Star LLC supplies soft starters in Oman, with Schneider Electric Altistart 22, Altistart 48 and Altistart 480 units, the ABB PSR compact soft starter, soft starters from Danfoss (VLT MCD 600), Carlo Gavazzi and Lovato, and an Allen-Bradley motor controller currently listed, together with the Schneider Electric TeSys Track condition monitoring system. This is a small range, and other frame sizes can be sourced on request.
How a soft starter for a motor is selected
Selection starts with the motor full-load current and the supply voltage, then the duty. Pumps and fans are normal starts. Loaded conveyors, crushers, mills and high-inertia fans are heavy starts and need a larger starter or a higher current class for the same motor. The number of starts per hour matters because the thyristors heat up during each ramp. Other points in the type code are the control supply voltage, internal or external bypass, the number of controlled phases, connection in line or inside the motor delta, and a communication option such as Modbus.
Typical soft starter applications
Soft starters are used on fixed-speed centrifugal pumps, where a controlled stop ramp also reduces water hammer, and on fans, compressors and conveyors in water, power and process plants across the GCC. Where the process needs variable speed, an AC drive is the correct device instead. For a quotation, send motor power, voltage and full-load current, the load type, starts per hour and the control voltage.
What to include in your inquiry
These details let us quote the right item the first time.
- Motor power (kW) and rated current
- Supply voltage and number of phases
- Application (pump, fan, conveyor, compressor)
- Communication option
- Enclosure rating and ambient temperature
Missing some of them? Send what you have. A nameplate photo or an old part number is enough to start.
Brands in Motor Soft Starters
All brands →
Related categories
- Vibration Monitoring160
- PLC & I/O Cards102
- Industrial Communications98
- Automation Accessories65
- Controllers & Data Acquisition60
- AC Drives53
- Isolator & Barrier18
- Industrial Computers15
- Encoders13
- Safety Switches & Guard Locking10
- Automation Software9
- HMI Displays8
- Servo Drives4
- Robotics3
- CCTV & Security2
- Pneumatic Cylinders2
Request a Quote for Motor Soft Starters
Looking for a specific model, part number or brand in Motor Soft Starters? Send us your requirements and quantities. Seven Star LLC sources genuine industrial equipment for customers across Oman and the GCC and replies with a formal quotation.
- Genuine OEM products
- Supply across Oman & the GCC
- Formal quotation from our sales team
Free, no-obligation quotation · takes about 1 minute
Other enquiries: [email protected] · WhatsApp
Frequently Asked Questions
How do I size a soft starter for a high-torque or high-inertia load?
Use the motor full-load current as the base, then apply the manufacturer's heavy-duty selection table. Long starting times mean the thyristors carry several times rated current for longer, so the starter is normally chosen one or more frame sizes above the standard-duty selection. Give us the load type, starting time if known, and starts per hour, and we check the size against the manufacturer's data.
Soft starter or variable frequency drive?
Choose a soft starter when the motor runs at fixed speed and you only need to limit starting current and mechanical shock. It is smaller, simpler and produces harmonics only during the ramps. Choose a drive when the process needs speed control, high torque at low speed or energy savings at reduced flow. Starting torque with a soft starter is reduced because torque falls with the square of voltage.
What is a bypass contactor and do I need one?
Once the motor reaches full speed, a bypass contactor closes across the thyristors so the running current no longer passes through them. This removes most of the heat loss and lets the starter sit in a smaller, less ventilated enclosure. Many compact starters have the bypass built in. Larger types may need an external contactor, which must be included in the order.
Can a soft starter reduce water hammer on a pump?
Yes. Water hammer on pump stop comes from the flow collapsing suddenly when the motor is switched off. A soft starter with a deceleration ramp, or a dedicated pump or torque control function, lowers the motor torque gradually so the flow slows and the check valve closes gently. Select a model that offers this function, since basic starters only have a simple voltage ramp.
What information is needed to quote a soft starter?
Motor rated power, voltage and full-load current, the supply frequency, the driven load, starting duty and starts per hour, the control supply voltage, the ambient temperature inside the panel, and whether built-in bypass, motor protection functions or a communication module are wanted. For a replacement, the complete reference from the old starter's label lets us identify the current equivalent.