Regarding the various forms of motor drive, one supplied with high quality by Provolt, in addition to its inverters, are the soft-starters.

Like inverters, soft-starters control electric motors, but only at start-up, in order to limit the engine's starting current to avoid overloading the power grid when sized according to engine power. In addition, this equipment also provides various protections and controls, such as starting time adjustment, automatic starting, starting mode, etc.

But why have a soft-starter? If you use a motor with a high starting load, but don't need a variable control after starting, such equipment will be very welcome in your application, given its cost-benefit, where a soft-starter usually has the lower value than an inverter of the same power. But don't think that it doesn't provide you with high technology. Today we have a high sophistication of these equipment, where some models offer Modbus communication and various parameters for process automation.

The soft-starter works mainly to reduce the effort of the motor and electric conductors in the starting, through an electronic circuit with thyristors in the power phases. Some models need a by-pass contactor for them to work and other models already have this device integrated, which preserves the useful life and avoids unnecessary heating of the control electronic circuit, resulting in an improvement in the efficiency of the equipment. In addition to avoiding energy waste, it also makes better use of and more efficient the energy delivered by the utility.

Another benefit of this equipment are the various protections. For example: against overload, overvoltage, phase sequence, unbalance or lack of phase among several other controls. These can be configured according to customer and application needs, such as: starting torque limit, acceleration ramp and shutdown ramp, etc.

Thinking about all the benefits of this equipment, Provolt currently supplies two Soft-Starter lines, the SSP and the PR5000. The SSP model is 100% national, produced and developed in our factory. The PR5000 line, on the other hand, is our imported line, both of them have factory assistance and a 1-year warranty.

What is the difference between these models? The SSP is a Soft-Starter already mounted on a panel, with a by-pass contactor and complete automation for air compressors, with outlets for relief valve and bleeder, pressure switch inlet, oil level switch, hour meter, remote start and provides minimum current protection, current unbalance protection between phases and current control start.

The PR5000 line, on the other hand, includes the PR5300 model, which has Modbus communication (RS485), detachable HMI, trip control in three phases, 5 simplified PLC functions and 5 starting modes. A difference between the previous line (PR5200) is that the PR5300 does not need a by-pass contactor to work.

Thinking about the customer, we present our equipment providing the knowledge you need to choose the model that best meets your demand, reaching our goal of satisfying you with high-tech and quality equipment, with a committed and trained team to better serve our partners during purchase, installation and any maintenance.

Written by: Daniel Nicolas Cunha and Arthur Lenzi Alvise

October 19, 2021