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Eaton SC9000 Series MV VFD Repair and Overview

Eaton SC9000 RepairEMA repairs and provides preventive and predictive maintenance on  the Eaton SC9000 MV VFD.  We  have a fully functional test stand for these units. We repair most Medium Voltage VFDs including the Eaton SC9000, the Siemens Robicon Perfect Harmony, the Toshiba T300MVi , Ansaldo / Ross Hill, ABB, Yaskawa, and others. 

Here’s a short overview of the Eaton SC9000:  The Eaton SC9000 series MV VFD is a 24 pulse three level topology VFD with integrated phase shifting transformer. In today’s market MV VFD topology ranges from two level all the way to nine level phase to neutral. The higher the level the more motor friendly the VFD is to existing motors. So three level topology MV VFDs are on the lower end of the scale.

Most manufacturers supply output filters to go with three level topology MV VFDs to protect existing motors from damage due to high output noise. The SC9000 can be supplied with an output filter to  make it motor friendly for existing motors. The rectifier section is easily accessible and easily serviceable in the field. The inverter section however, which incorporates the IGBTs, gate driver sections and bus capacitors are encapsulated in what is known as “Powerpole”. Encapsulating the inverter section does have some advantages. For example,  in corrosive environments the electronic boards will not be directly exposed to the outside air. We have seen H2S in off shore oil platforms and water treatment facilities where the H2S reacted with the electronic boards of the Medium Voltage VFDs and caused premature board failures.

The downside to the Eaton SC9000 is that the EP (encapsulated Power pole) is not field repairable provided the damages to the VFD are within the “Powerpole.” In some cases,  due to the encapsulation, they  may not be repairable at all. This can result in significant expense.  

The Eaton SC9000 MV VFD design architecture requires significantly  higher DC voltage on the DC link circuit of the VFD on the capacitors than most VFDs on the market. For example the DC link voltage can be up to 7500V DC on a 4160V VFD and 4320V DC on the 2300V VFD.

One nice feature is the innovative softmag SC9000 pre-charge circuit which softens the inrush current on the phase shifting transformer. This helps prevent premature transformer failure during pre-charging.

Cooling of the inverter section/powerpole is an important part of the longevity of any MV VFD. It is especially important in the SC9000 given the fact that it is encapsulated so the SC9000 uses the heat-pipe technology to help cool the “powerpole”.

EMA has invested in a fully functional test stand for the Eaton SC9000 for testing in-house repairs and also offering hands-on training for our customers. We offer predictive and preventative maintenance on the Eaton SC9000 series MV VFDs, as well as repair. 

Contact us by calling 770-448-4644 OR any of the contact methods on this site, including live support.  We have three offices to serve you in Atlanta, Georgia, Upstate New York, and Pennsylvania. 

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