EMA services all makes and models of Medium Voltage Variable Frequency Drives and the Eaton SC9000 is a drive we see often.
Eaton is well known for industrial automation in a variety of sectors, including switch gear and VFDs. In fact, our load stands at EMA utilize Eaton Switchgear. Eaton’s workhorse Medium Voltage VFD is the SC9000. As with any medium voltage VFD, there are pros and cons to this drive.
Pros:
- 24 pulse isolation transformer for harmonic mitigation.
- This is common among most manufacturers.
- Comes standard with a fully integrated isolation switch with associated fusing.
- This is not a standard for many manufacturers, but Eaton integrates it into their drives; Eaton is well known for their switchgear.
- Pre-charge circuitry for “softly” charging the transformer and DC Bus.
- Some manufacturers do not utilize pre-charge circuitry.
- Capable of synchronous transfer.
- Not every manufacturer offers this, but it is a great feature if you want to use one drive to bring up multiple motors and transfer them to utility power. This is common in certain oil and gas pumping applications.
- The SC9000 uses film-type capacitors, which have a longer useable life than the more common electrolytic capacitor used by many other manufacturers.
Cons:
- The SC9000 utilizes a three-level topology, which saves on the number of components but is less “motor friendly” than some of the higher level topologies that are in the market.
- In many cases, additional output filters are needed when using the Eaton SC9000.
- Because of the 3-level topology, the drive switches at over 7000 volts DC (in 4160V models), which is more susceptible to catastrophic failure and, as mentioned above, is less “motor friendly” because of the higher peak to peak spikes that can break down motor insulation.
- Because the inverter section switches such high voltage, it requires higher-rated components which are more expensive and less available.
Inverter Power Pole: A Pro And A Con
The entire inverter section comes in an “encapsulated power pole” which houses the components in a gel-like, potted material that keeps it from corrosion and other environmental related issues. The drive may have 1 or 2 power poles depending on the size of the drive.
The power poles roll in to stabs in the back of the drive which makes changing power poles fairly quick and easy; EMA has plenty of experience changing them.
However, because the power poles contain the entire inverter section, they are extremely expensive and because of the potted material all the components are housed in, they are not field repairable and often not repairable at all.
We have seen instances where a new power pole was almost as expensive as an entirely new drive!
As medium voltage drives become more and more common in modern production facilities, we anticipate the Eaton SC9000’s market share to increase. At EMA, we’re very familiar with this drive, and do troubleshooting and preventative maintenance on them all over the country.
Eaton struggles to support this drive due to lack of trained engineers, but EMA has worked tirelessly to become experts at repairing and servicing the Eaton SC9000 and we offer customers an alternative to using the manufacturer for service.
Do you need service or maintenance on your Eaton SC9000 Medium Voltage Variable Frequency drive? Let us help you! With over 35 years of experience in VFDs, we know what we’re doing.
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