Correct name for a specific design of electric machine 1

[murpia]

Hi,

I thought this might be a good place to ask a question about a specific design of electric machine.

Trying to search online for information is difficult if you don't know the right terminology. For example, I could not easily search for information on matrix converters until I knew they were called matrix converters...

The design I am interested in would consist of a stator or stators with both an internal and external rotor. Therefore having two shafts. Mechanical power transmission can then be done between the two shafts at differing speeds & torques, modulated electrically.

This is similar to a coupled generator-motor arrangement but more compact.

Does this arrangement exist and if so what would it be called so I can do some more research?

Thanks, Ian

 

[imcjoek]

Mechanical power transmission can then be done between the two shafts at differing speeds & torques, modulated electrically.

Hysteresis clutch?
Magnetic particle clutch?

 

[racookpe1978]

Two shafts, one inside the outer?

The airplane engine community has tried for that for about 90 years, and have succeeded only once. (Tu Bear contra-rotating props work fairly well. The rest have failed to perform reliably.)

 

[ScottyUK]

Something similar to this arrangement is used in the rotary UPS systems manufactured, for example, by Anton Piller and Eurodiesel. In their design a high-mass rotor rotating at a speed corresponding to twice line frequency is used as an energy store. During a power interruption the stored energy is delivered to a synchronous machine and keeps that machine rotating at a near-constant speed. The energy store provides sufficient ride-through time to allow a diesel engine to start and accept load. Have a look at

http://www.euro-diesel.com/english/system-description/110/2

for a summary. There's a link to an animation near the bottom of the page.

 

[Strong]

Google: concentric shaft electric motor
Google: 2 speed drive
Walt

 

[CJCPE]

It seems like you may be describing an eddy-current clutch or coupling, also called a magnetic coupling or drive. An EC clutch has an input rotor, and output rotor with a variable DC magnetic field produced either by a stator or by a coil in one of the rotors energized through slip-rings. They are not used much anymore because they are inefficient, but they are pretty rugged and the control unit is simple. I believe that the same thing has been done using variable-position permanent magnets.

This is the successor company to the company that introduced them in the 1930's.

http://www.dynamatic.com

CJC

http://www.vfdriveinfo.com

 

[murpia]

Just a quick thanks for the info, the term 'eddy current' clutch / coupling / drive is what I was looking for.

Ian