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EMA Inc.

Rockwell Allen Bradley Powerflex 7000 Shorting Issue

We recently had a customer sustain significant damage on their 2500 HP Allen Bradley Powerflex 7000 medium voltage VFD due to degraded rubber O-rings designed for reducing noise between the SGCT and the heat sink it sits on. After some digging, we found this to be a known problem in this Rockwell medium voltage VFD. In November of 2016 an engineering note was released in the Rockwell Knowledge base regarding the Powerflex 7000 medium voltage VFD: note 969771 states: “In

Precharge Circuit for Medium Voltage MV VFD

It is common practice to have a precharge circuit in almost all low voltage VFDs, although this is not the case in MV VFD design. Inrush current can cause major damage to a medium voltage VFD. This blog describes how and why this damage occurs. 

Medium Voltage VFD Field Service

Field Service on Medium Voltage VFDs

Our primary business has become field service on medium voltage VFDs. If you need Field Service on a medium voltage VFD..

Medium voltage VFD (MV) quick delivery

Medium Voltage VFD (MV) Quick Delivery

We have a number of medium voltage VFDs in stock for quick and even immediate delivery. Horsepower ranges from 500 to 3500 horsepower. Some of these medium voltage VFDs are reconditioned units with a full warranty, and some are factory new. All are sold on a first-come, first-served basis. You are welcome to inspect them at our Norcross, GA, (Atlanta) facility. We’ll also be happy to send you pictures.

GE multilyn repairs

We Repair GE Multilins 469, 750 and Others

EMA repairs GE Multilins. We repair the Multilin 469, Multilin 750 and most others. Repairing Multilins is not a new business for us, we’ve been repairing GE Multilins for some time now.


Remote Monitoring of Critical VFDs and Drives

Variable Frequency Drives (VFD) are often used on critical applications in remote locations. Examples of remote and critical VFD applications would be oil and gas pipelines, water treatment and pumping, and oil production. Remote monitoring of these units can be of paramount importance.


Pipeline Medium Voltage VFD Specifications Overview

We’re seeing increased inquiries regarding pipeline VFD specifications for pipeline VFD applications. The following is a general overview that may prove helpful. We cover Siemens, Allen Bradly, Yaskawa, Toshiba and Nidec (Ansaldo).


PQube3 VFD Remote Monitoring Tool

Per the IEEE, electrical equipment that regularly undergoes preventive maintenance is less likely to fail compared to equipment not subjected to preventive maintenance. See our blogs on preventive maintenance.

toshiba medium voltage input section

Field Service and Repair on Toshiba T300MVI Medium Voltage VFD

The Toshiba T300MVI medium voltage VFD is a popular drive, and we offer field service and repair, including power cell repairs.

Toshiba t300MVI in stock

Toshiba T300MVI 2000 HP Medium Voltage VFD in Stock

We have two brand new, unused, Toshiba T300MVI 2000 HP Medium Voltage VFDs in stock. These are from a cancelled project, were never installed and will carry a full warranty.