Eaton Logo

Use of C440 overload with Soft Starters

When considering using a soft starter with SSOL's such as the C440 or XTOE to protect motors that have a current rating less then the minimum set point of the S801+ ,S811+ or our DS7. We offer that you can consider using these SSOL's with the following comment.

There might be a issue during starting with low starting torque.  We do  know how accurate the C440 current measurements will be if the S811+ is using a very low starting torque setting and the ramp time is extended. When the starting torque setting is low, the voltage waveform gets highly distorted from a pure sine wave, due to the “notching”. If long start ramp times are used, it could become an issue.  However, under most applications using small motor loads, they typically do not have long ramp times and are up to speed rather quickly. We have not tested these two devices together to provide any validations  in this regard.

C440 / XTOE Product Overview

S811+ /S801+ Product Overview

DS7 Product Overview