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Motor Information
DC MOTOR HORSEPOWER RATINGS:
The Horsepower ratings for Electric Motors are a little deceiving,
Electric Motors have about 3 times the torque than gas motors and the
peak horsepower is basically limited only to the controller used. An
Advanced DC motor rated at 17.5 hp will power a Geo-metro car to over
70 mph.
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Series Wound DC Motors:
Most Large applications use a series wound DC motor. There aren't
any magnets, but instead a field winding of wire that becomes an
electro magnet when current flows through it. A series motor means that
the same current that flows through the rest of the motor (armature)
also flows through the field windings. Heavy duty wire and connections
are used for every aspect of the motor to withstand the high current.
There are also some benefits concerning torque. The motor is wired so
that the negative output side of the controller goes into the field
winding, the field winding output is shorted to the armature, and the
other armature connection is hooked to the positive side of the battery
pack.
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Permanent Magnet motors:
These motors are about the best and most efficient motors you can
find at reasonable prices for light electric vehicles and general
industrial applications. Reliability is higher than separately excited
field motors due to fewer electronic parts and no possibility of
shorting out the field. They operate more efficiently at lower speed
control than separately excited field motors as well, and produce more
horsepower in a smaller, lighter motor. Horsepower ratings on these
motors is the nominal rating at the motors most efficient operation.
Each motor can deliver considerably higher HP for intermittent periods
during actual use.
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Motors to use in High Power Applications:
"The brushed series DC motor is the best overall motor for
affordable High Power drive applications. AC motors operate at high rpm
that have to be stepped down and have expensive and complex speed
control systems. Brushless DC motors (actually another kind of AC
motor) also require expensive and unreliable controllers. Permanent
magnet motors are very efficient, but only in a very narrow rpm band,
and quickly lose their efficiency in the varying speeds of normal
usage. Shunt and compound motors are more expensive to build and have
poorer acceleration than series motors.
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