Powerex sells off the shelf IGBT assemblies for 1200V, add the appropriate control electronics and you have an inverter than can handle the 750V used in parts of Blighty. There is at least one company selling inverters intended to be used at 3kVDC.
AC induction motors are generally smaller, lighter and cheaper than DC series motors with eqivalent mechanical output.
- Erik
The CTA 5000-series rapid transit cars now being delivered are equipped with inverters which convert 600 volt DC to AC for the traction motors.
According to the article the equipment "dates from the 1980's" so it is about 30 years old. The DC traction motors are probably at the end of their useful life. And they are electromechanical. However, the cars themselves have a fair amount of life left in them.
The new equipment consists of solid state inverters which presumably will convert the 750 volt dc now available to ac. That is, the power source will not be changed. However, the new inverters will enable the cars to use ac traction engines. Using ac for traction seems to be the state of the art right now.
Class 455 EMUs in England even though 20+ years old are going to be converted to AC traction which the Brits believe will save money in the long run and add additional capacity without building more EMUs.
http://www.railwaygazette.com/news/passenger/single-view/view/south-west-trains-emus-to-get-ac-traction-equipment.html
If this is a success will we see this as well in the US ?
Our community is FREE to join. To participate you must either login or register for an account.