Introduction: REPULSION START.....INDUCTION RUN MOTOR

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A large cast iron ( 12" jaw )  wood planer powered by a Repulsion-Start  Induction-Run motor.

This is a class of motor that overcomes the induction motor's low starting torque
and incorporates the large starting torque,
while loosing the noise and brush wear of a repulsion motor.

For those who are not interested in the speed torque can skip the next step.

Curious about IRON PENNIES well you are in luck.

Step 1: THE NEED... THE NEED............. FOR TORQUE and Speed

The starting of a large Planer takes more toque then an induction machine can provide
in accelerating the mass of the single edge blade in a massive flywheel.

The first graph ( Third Pic ) plots the speed torque of a repulsion motor
which has a strong starting torque at low speed.

See the ( First  Pic ) a simplified repulsion motor wiring diagram.
.
After 40 seconds the repulsion motor reaches speed and the brushes lift off the
commutator turning the motor into an induction machine for planing. 
Here is a pointer to an actual repulsion motor starting a planer wind-up
that you can see and hear.

See the ( Fourth Pic ) a simplified Induction motor wiring diagram.

The second graph ( Sixth Pic ) plots the speed torque of a Induction motor
which has almost no starting torque at all  ( used for fans )..

Step 2: BIG CAST IRON PLANER

IF you skipped here from the Introduction you may want to use this pointer to see and hear
an actual repulsion motor wind-up sound starting this planer.

A safety cover blocks access to the very dangerous spinning steel cutting flywheel blade.

Step 3: WHATS a REPULSION MOTOR

As you can see the repulsion motor uses stationary brushes on the rotor
with attached commutator to achieve the starting torque.
This configuration is much like a shunt motor.

Step 4: USING THE PLANER

Here are some pictures of the plane taking a cut  on a solid 4×4 segment.
This is a pointer to a planning operation you can watch and hear.

Note how the safety guard keeps the errant fingers away from the blade.

I have trimmed a solid core door in three passes to fit an older door jamb
on this machine.
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