Are Permanent Magnet Machines Inefficient at Lower Power Levels?

Thread starter annalisemalta
Start date Oct 1, 2012
Tags

Machines Magnet Permanent magnet

AI Thread Summary

Permanent magnet machines are not inefficient at lower power levels, unlike induction machines. Small motors commonly utilize permanent magnets due to their efficiency across various power levels. It's important to note that permanent magnet motors also incorporate electromagnets in their design. This combination allows for effective performance even when operating below their designed power capacity. Overall, permanent magnet machines maintain efficiency regardless of power output.

Oct 1, 2012

annalisemalta

Hi,

when a perment magnet machine is designed for a particular power but is operated at a much lower power, is it inefficient as with induction machines?

Thanks

Engineering news on Phys.org

Oct 1, 2012

Antiphon

No it isn't. That's why all small motors use permanent magnets.

Oct 2, 2012

russ_watters

Mentor

Insights Author

There may be a misunderstanding here: a permanent magnet motor still uses electromagnets too.

Thread 'Query on Isentropic relationships (such as PV^gamma = constant)'

Hi all, I have a question. So from the derivation of the Isentropic process relationship PV^gamma = constant, there is a step dW = PdV, which can only be said for quasi-equilibrium (or reversible) processes. As such I believe PV^gamma = constant (and the family of equations) should not be applicable to just adiabatic processes? Ie, it should be applicable only for adiabatic + reversible = isentropic processes? However, I've seen couple of online notes/books, and...

View full post »

Thread 'Dry sump pump issue'

I have an engine that uses a dry sump oiling system. The oil collection pan has three AN fittings to use for scavenging. Two of the fittings are approximately on the same level, the third is about 1/2 to 3/4 inch higher than the other two. The system ran for years with no problem using a three stage pump (one pressure and two scavenge stages). The two scavenge stages were connected at times to any two of the three AN fittings on the tank. Recently I tried an upgrade to a four stage pump...

View full post »