Need advice on motor selection and sourcing

[Will]

I'm an electrical/computer engineer about to take my first steps into
the hobby car/robot world but I need a little help with my motor
knowledge. I'm designing a system to run off battery power so i want
to find the most efficient type of motor with respect to electrical
power in versus mechanical power out. Small size is a big plus too,
and preferably nothing overly complicated to control. I've never
worked with stepper motors, but they seem like more trouble than they
are worth unless you want high accuracy on shaft position. I'm
looking for something I can apply a DC or maybe PWM signal to and it
will turn at variable speeds, in both directions. I know a lot about
H-Bridges and the like, so I'm more interested in the motor side of
things. Which motor types (coreless, brushed, brushless, etc.) are
the most efficient? Who makes them cheap and small (small more
important than cheap)? What quirks to controlling them are there?
Thanks for the info.
-Will

[Jonny Hodgson]

Will <lark...@aol.com> wrote in message news:5faf6114.01112...@posting.google.com...

As far as we car guys are concerned, there's only one size of
motor*: the 540 (based on a Mabuchi spec from years ago).

We either run regular, three-pole permanent magnet brushed
DC motors (which are rough and inefficient), or (recently)
brushless devices (effectively ?three-pole stepper motors)
with permanent magnet armatures, which are sold as a set
with their own bespoke controller.

Aveox are a big name in brushless, with Novak bringing out
a car-specific system soon and Modeltech also marketing a
car system.

Don't know about reverse (we only go forwards as a rule)
but apparently brakes have been a problem until recently;
the aeromodellers have been using brushless for years, but
their systems tended to blow up on entry to a corner ;-)

Anyway, I'm cross-posting this to .air since I suspect
they'll have more experience in the available sizes and
types of motor.

Good luck!
Jonny

*All right, you lot with the E-Maxxes can just be quiet, okay?

[RonaldB]

Will,

brushless motors are in general the most efficient, but are still
pretty expensive and require dedicated controllers (which are
expensive, too).

Brushed DC motors are still pretty efficient and can be picked up
cheap and in every imaginable size. Speed controllers can use simple
PWM and are widely available, at least in the RC business.

Stepper motors are inefficient, have a poor power-to-weight ratio and
require dedicated controllers, but their main advantage is the ability
to position the shaft exactly and repetitively without the need for
feedback.

Take your pick based on the most important property.

Regards,
Ronald.

lark...@aol.com (Will) wrote in message news:<5faf6114.01112...@posting.google.com>...

[zwge...@gmail.com]

China Shenzhen ZHAOWEI Machinery & Electronics Co. Ltd engages in designing, manufacturing and marketing all kinds of electric motors. They are mainly suitable for the following applications: smart home application used in smart kitchen and laundry, medical instrument for personal care, smart E-transmission applied in automobile, industry automation applied in telecommunication and a great variety of plastic/metal planetary gearbox in different sizes.
In order to develop the oversea market, we are current seeking new partners around the world to create a bright future together. ZhaoWei is a right choice and excellent partnership with sincere services.

Company: Shenzhen ZHAOWEI Machinery & Electronics Co., Ltd
URL: http://www.zwgearbox.com/
Contact: Annie Liu
Tel：+86-755-27322652
Fax：+86-755-27323949
E-mail:sa...@zwgearbox.com
Add: Blk. 18, Longwangmiao Industry Park, Fuyong Tn., Bao’an Dist., Shenzhen 518103, Guangdong, China