Why Industries Trust Authorised Carlo Gavazzi Soft Starter Distributors

Why Industries Trust Authorised Carlo Gavazzi Soft Starter Distributors

14 May 2026 · 9 min read · Trans-Digi Global

Industries buy Carlo Gavazzi soft starters through authorised channels for the same reason they specify the brand: they want the published performance, the certifications and the manufacturer support to apply to the unit in their panel. For the compact RSGD range, that published performance is specific: starting current cut to about 3.5 times motor current, Class 10 overload protection built in, and ratings from 12 to 100 A in 45 mm and 75 mm wide housings.

In this article

• Who Carlo Gavazzi is
• Why soft starting matters more with modern motors
• RSGD at a glance
• How to select an RSGD
• Soft starter or VSD?
• What the authorised route gives you in practice
• Soft starters in our project work
• Frequently asked questions
• Get the right soft starter
• Sources

A soft starter is an electronic device that ramps up the voltage to a fixed-speed AC motor at start, and ramps it down at stop, to limit inrush current and mechanical shock. Trans-Digi Global supplies the Carlo Gavazzi RSGD soft starter in Singapore, and as our partners page states, everything we sell comes through authorised channels, with the documentation to prove it.

Who Carlo Gavazzi is

Carlo Gavazzi is an international group that designs, manufactures and markets electronic equipment for industrial and building automation, including sensors, monitoring relays, solid-state relays, energy management systems and soft starters. Its products are marketed across Europe, the Americas and Asia-Pacific through 24 of its own sales companies and more than 60 independent national distributors (Carlo Gavazzi). Its typical customers include original equipment manufacturers (OEMs) of packaging, conveying and HVAC equipment, which is where the compact RSGD fits best.

Why soft starting matters more with modern motors

Singapore’s National Environment Agency set minimum energy performance standards (MEPS) for motors at IE3 level, noting that electric motors accounted for about 80% of the 2015 electricity consumed by companies regulated under the Energy Conservation Act, and that electricity typically makes up over 95% of a motor’s life-cycle cost (NEA consultation on MEPS for motors).

Higher-efficiency motors bring a side effect at start-up. Carlo Gavazzi’s RSGD/RSGT brochure compares typical starting currents as multiples of motor rated current:

Lower starting current, the brochure notes, “avoids nuisance trips of protection devices and reduces mechanical shocks during motor starts.” That matches the US Department of Energy’s observation that starts and stops are hard on motors “because of repeated stresses from starting currents, and acceleration and deceleration of mechanical components” (DOE motor and drive system sourcebook).

RSGD at a glance

From the Carlo Gavazzi RSGD datasheet:

• Ratings: 12 to 45 A in a 45 mm wide housing; 55 to 100 A in a 75 mm wide housing; 220 to 400 V AC (RSGD40) or 220 to 600 V AC (RSGD60).
• Control: two-phase control with a self-learning algorithm that adapts the start to the load; only three settings (full-load current, ramp-up, ramp-down).
• Integrated bypass: the unit goes into bypass once the motor reaches full speed.
• Protection: integrated electronic overload protection (Class 10) on the VD210, VX210, VX310 and VX311 models.
• Soft stop: torque control during ramp-down for smoother deceleration, which Carlo Gavazzi says eliminates water hammer when stopping pumps.
• Communication: Modbus RTU over RS485 on the “C” models.
• Standards: EN 60947-4-2; UL and cUL listed; CCC.

Mind the temperature rating

Soft starters are rated at a stated surrounding temperature, and Singapore panels often run warm. The RSGD datasheet gives the derating clearly:

The brochure adds that when the temperature inside the panel exceeds the soft starter’s rated temperature, typically 40 °C, the unit must be derated. Size for the panel’s real internal temperature, not the room’s.

How to select an RSGD

1. Note the motor full-load current (FLC) and supply voltage from the nameplate.
2. Identify the load type. The datasheet’s application table suggests a trip class for each, for example class 5 for a centrifugal pump that starts in under 10 s, class 10 for conveyors, class 20 for centrifugal fans over 0.5 m diameter, and class 30 for crushers.
3. Pick the model from the datasheet selection table by FLC and trip class. A heavier trip class can call for a larger rating than the FLC alone suggests.
4. Check starts per hour. Soft starters are typically designed for 10 to 20 starts per hour; the RSGD 75 mm models are rated for 10 starts per hour at the rated overload cycle (AC53b: 3-12:348, meaning three times rated current for 12 seconds followed by 348 seconds off).
5. Apply temperature derating for the panel’s internal temperature.
6. Choose the control voltage (110 to 400 V AC or 24 V AC/DC) and whether you need Modbus.
7. Check the overload arrangement. For class 20 or 30 operation, the datasheet notes an external overload device may be required.

Soft starter or VSD?

A soft starter only manages the start and stop; once the motor is up to speed, the RSGD switches to bypass and the motor runs at full speed from the supply. A variable speed drive controls speed continuously. The US Department of Energy’s Motor Systems Tip Sheet #11 explains why that matters on centrifugal pumps and fans: power varies with the cube of speed, so a 20% speed reduction can cut input power by about 50%. If the load must run at full speed whenever it runs, a soft starter is the simpler and more compact choice. If flow or pressure varies through the day, a VSD is worth evaluating for the energy saving. For a full comparison with a decision matrix by pump duty, see soft starter vs VFD: which should your pump use?

What the authorised route gives you in practice

• Traceable, genuine product, so the certifications listed above apply to the unit you install.
• A manufacturer warranty that will be honoured, one of the commitments on our partners page.
• Technical escalation to the manufacturer when a question goes beyond the datasheet.
• Documentation for tender submissions and as-built packs.
• Honest product-neutral advice. Because we carry several ranges, we can recommend what suits the duty, and explain why.

That last point matters with soft starters. The RSGD is designed for compact, fixed-speed duties up to 100 A. For larger motors or more advanced protection and connectivity, we may point you to the Schneider ATS480, the Schneider ATS22 or the Himel HASXS. Where the process needs speed control, a VSD is the right tool.

Soft starters in our project work

Our published soft-starter projects use the Himel HASXS rather than the RSGD, but they show the application discipline we bring to any soft starter:

• Singapore Rail Test Centre (LTA, 2023): a 132 kW HASXS for the fire pump system, with parameter settings, testing and commissioning.
• Kim Chuan Depot Extension (LTA, 2024): a 160 kW HASXS for the fire pump system in an underground rail and bus facility.
• Gateway East (Singapore Land Group, 2023): more than ten HASXS units, 37 to 55 kW, as standby starters for chilled-water and condenser-water motors over ten years old.

Frequently asked questions

What is the Carlo Gavazzi RSGD?

A compact three-phase soft starter for AC induction motors up to 100 A, with two-phase control, a self-learning start algorithm, integrated bypass and, on most models, built-in Class 10 overload protection.

How much does an RSGD reduce starting current?

Carlo Gavazzi’s brochure gives a typical 3.5 times motor rated current with the RSGD, against 6 to 15 times for direct-on-line starting depending on motor efficiency class.

Does the RSGD include motor overload protection?

Yes, on the VD210, VX210, VX310 and VX311 models (Class 10). For class 20 or 30 duties an external overload device may be required.

Can I use an RSGD on a pump?

Yes. Pumps are a typical application, and the torque-controlled soft stop helps prevent water hammer.

What is the difference between RSGD and RSGT?

Both are Carlo Gavazzi self-learning soft starters. The RSGD controls two phases; the RSGT controls all three, giving a typical further 10% reduction in starting current and less than 2% current imbalance at start, per the brochure.

Do you hold RSGD stock in Singapore?

Our RSGD product page lists local Singapore stock. Send us the motor FLC, voltage and application and we will confirm the model.

Get the right soft starter

Send the motor rating, voltage and application and we will confirm the right RSGD, or a better-suited alternative, and its availability. See the Carlo Gavazzi range, our services, or contact us.

Related reading: Why Choose an Authorised WEG Distributor in Singapore · Schneider ATS22: A Reliable Soft Starter · Why the Himel HDR3S Thermal Overload Relay Is Essential

Sources

• Carlo Gavazzi: RSGD three-phase AC motor soft starter datasheet (45 mm and 75 mm)
• Carlo Gavazzi: RSGD/RSGT self-learning soft starters product brochure
• Carlo Gavazzi: group overview
• IEC 60947-4-2:2020, Semiconductor motor controllers, starters and soft-starters
• IEC 60947-4-1:2023, Contactors and motor-starters
• National Environment Agency (via REACH): Public consultation on introducing MEPS for motors
• US Department of Energy: Improving Motor and Drive System Performance, A Sourcebook for Industry
• US Department of Energy: Motor Systems Tip Sheet #11, Adjustable Speed Drive Part-Load Efficiency
• Trans-Digi Global: Our Partners
• Trans-Digi Global: Carlo Gavazzi RSGD soft starter product page