In article ,
harry writes:
Further to our recent discussion, I checked out eight different mowers
at Payless today. All had geared reduction drives plus some form of
soft coupling between the motor and blades. The only exception was a
non-grass collecting Flymow which was direct coupled, ie cutter on
motor shaft.
The grass collecting Flymows had gearoxes (or it may have been a
toothed belt). A speed reduction device anyway.
I was getting funny looks, I couldn't dismantle them of course.
So, as I suspected, the Naturist Philosopher was right.

I don't know what thread you're looking at.

Universal motors (i.e. with brushes) have to be geared down
to driver mower blades - they spin too fast otherwise.
Universal motors are used in cheaper low grade mowers of the
type you'll find in the sheds. Universal motors are dirt cheap
but are completely wrong torque profile for grass cutting,
which is why they slow down under load just when you need more
cutting power, and deliver much less.

Induction motors drive mower blades directly.
You'll find these on higher spec mowers, but you may have to
go to a mower specialist. The torque profile of an induction
motor is much more ideal for grass cutting - max torque at
nearly full speed (so it will maintain speed and cutting
power under load), rather than at locked rotor. Expect to pay
more, but also expect longer motor life. Also, the induction
motor is significantly more efficient, and unlike the cheap
universal mower motors, IME induction motors in mowers don't
waste power heating themselves up way too hot to touch. As a
result of this, don't be surprised to find they are lower power
rating for same width cut, because they manage to use more
of the power for cutting and less wasted in the motor.
No motor brushes to wear out either.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]