Andrew Gabriel wrote:

In the case of lawnmowers, I suspect the use of universal
motors is to make mowers into consumables, which people
will thus tend to change every few years.

Ditto cheap high pressure cleaners. The £30 B&Q jobbies have a motor life
of 10-12 hours. Even a cheap Chinese induction motor will run for 50-60
hours. Qua;ity industrial machine will have an induction motor rated at
800-1000 hours.

Just about every
characteristic of a universal motor is inappropriate for
a lawn mower. You can find mowers with induction motors,
but they tend to be in the better quality less well known
makes, which you have to buy from specialists rather than
DIY sheds.

Ditto cheap high pressure cleaners.

Also, universal motors generally run
much faster, indeed much too fast for many applications where they
need to be geared down (e.g. mowers, drills, etc).

Indeed. High pressure pump wants to run at 1400 rpm, or 2800 at a pinch.
The cheapo HPCs use a ring gear to slow the motor down.

I can see the logic in that, but I've always assumed (from my HPC
experiences) that induction motors were much more expensive.

I don't see why they should be technically. It may be a question
of supply and demand, what the market will bear, etc.

Maybe mass production. Many el cheapo HPC's use domestic vacuum cleaner
motors.

Dave