There has been much discussion about the merits
of permanent magnet "PM") motors and where to buy
them etc. However, shunt wound motors (fixed
electromagnet replaces the permanent magnet with its own
separate circuit) has the same performance advantages of
PM (higher torque at higher RPM compared to series
wound motors that are commonly used in electric cars
and golf carts, high efficiency compared to series
wound). Furthermore, the magnetic field of a shunt wound
motor is easily controlled (can be altered in response
to conditions), unlike the PM and possibly could
generate very high magnetic fields without going to the
expensive rare earth element high power magnets, thus
lowering cost. Still further, the fixed magnetic field,
unlike the PM magnetic field, does not decay with time,
and such decay is not accelerated by high speed
conditions (all permanent magnets lose their power over
time).<br><br> I note that ELCO (Electric Launch Company in the
Lake George region of upstate NY) sells electric boats
with shunt wound motors and believes that these
provide superior performance over the series wound that
many of the members have discussed in this forum.
<br><br>Does anyone know where to find 5-10 hp shunt wound
motors? <br><br>Is there some disadvantage to shunt wound
outside of having to use a very simple and cheap
controller for the shunt wound fixed magnet? <br><br>ELCO
has a long history of using shunt wound and points
out that these are very reliable and quieter than PM
motors. What experience does anyone have with a shunt
wound? What efficiency is achieved over a wide rpm
range? Can you get high power output for short times? Do
you need to increase the shunt circuit power to
increase the fixed magnetic field under high power
conditions, as would normally happen in a series wound fixed
magnetic field coil under the same high power conditions
(i.e. as you increase power to the armature of a series
wound, you also automatically increase power to the
permanent magnet coil)<br>It seems to me that shunt wound
motors have some real advantages that may be overlooked.
