Category: Soft Starters

Everything you need to know about Soft Starters, with technical information provided by our expert team.

What are the top safety tips for electrical engineers?

Seven steps that save lives// While we usually focus our weekly technical releases on practical assistance for today’s engineers, nothing is more important than understanding how to work safely. As an example of electrical safety procedures, we will discuss the safe working procedures used by HV field technicians – the ‘Seven steps that save lives‘. …

Continue reading

What setting parameters are available on softstarters?

Six common setting parameters available on most softstarters// This technical article includes a short description of six common setting parameters available on most softstarters. Other settings may be available depending on the type of softstarter and manufacturer. The setting can be done either by adjusting potentiometers, changing dip switches, using a key pad, a computer or …

Continue reading

How do soft starting and VSD motor starting compare?

Soft starting // A soft starter is, as you would expect, a device which ensures a soft starting of a motor. A softstarter has different characteristics to the other starting methods. It has thyristors in the main circuit, and the motor voltage is regulated with a printed circuit board. The softstarter makes use of the …

Continue reading

How do I select soft starters for use with IE3 Motors?

There are many misconceptions about motor starting. It is often believed that the start current of a motor under full voltage conditions depends on the driven load, but this is totally incorrect. The start current of the motor depends on the motor design, rotor speed and stator voltage from zero speed until full speed is …

Continue reading

I have a 90kW motor with soft starter 90kW installed. How much kVA Generator do I require for the motor?

Limited information means you need to make a few assumptions on power factor and efficiency. Assume PF of 0.75 and efficiency of 90% kVA = (kW / Power factor) / efficiency so kVA = (90 / 0.75) / 0.9 = 133.33 kVA So 133.33 kVA minimum but better to add a little extra to be …

Continue reading

Why use a bypass contractor with a soft starter?

The Bypass contactor opens when the motor reaches full speed to reduce power (heat) losses in the solid-state power section. This translates to much smaller enclosures without need for special cooling. Also, the bypass contactor is internal to the soft starter, eliminating the need for additional devices, further reducing enclosure sizes and minimizing installation time. …

Continue reading

What is the difference between a VSD and a Soft Start Starter?

We are frequently asked, what the difference is between a variable speed drive and a soft starter? The difference is the speed that the motor can run when at full speed. With a soft start starter, the motor is reduced when voltage is started; and then when the motor is at full speed, or a …

Continue reading

Can a variable frequency drive replace a Soft start?

Yes, a variable frequency drive can replace a soft start starter, since most drives give you a current limiting ramp to start and stop your motor. BUT if you do not need to vary the production speed of your motor, then the soft start starter is still the correct product for the application. This is …

Continue reading

Can a variable frequency drive replace a Soft Start?

Yes, a variable frequency drive can replace a soft start starter, since most drives give you a current limiting ramp to start and stop your motor. BUT, if you do not need to vary the production speed of your motor, then the soft start starter may still be the correct product for the application. This …

Continue reading

What is the difference between a VSD and a Soft Start Starter?

The difference is the speed that the motor can run, when at full speed. With a soft start starter, the motor is reduced voltage started, and then when the motor is at full speed, or a timing circuit has timed out, a “running by-pass contactor” pulls in and the motor continues to run at full …

Continue reading