torque on generator question

Lets say we have a generator that consists of permanent magnets rotating about a stator consisting of a set of coils. When there is no electrical load on the generator there is not much torque applied against the rotor thus it spin fast. When we apply an electrical load on the generator the rotor slows down, or the generator must work harder in order to maintain the rpm. My question is, what exactly is going on in the coils to slow down the rotor? When you apply an electrical load resistance will be applied to the coils / circuit, but why does this effect the permanent magnet rotor? Sorry if it is a dumb question.

It's not a dumb question at all.

When a perm magnet generator has air coils (the whole thing is actually an alternator, not generator) there will be almost zero drag when the coils are open circuit.

But if you draw an electrical load from the coils by attaching a resistor etc that is providing an electrical power output from the alternator, and the power coming out can only be produced by power going in when turning the shaft.

So the more electrical power you draw from the coils, the harder the shaft is to turn.

If you can measure the shaft power going into the alternator, and measure the electrical power coming out, you can know the efficiency of the alternator (under those conditions).

Specifically the spinning magnetic field from the rotor magnets generates a voltage in the stator coils. When a load is connected, current starts to flow in the stator coils due to the voltage across the load. The magnetic field generated by this current opposes the magnetic field from the rotor. This causes a drag on the rotor tending to slow it down. To maintain the rotor speed more torque (equating to power) must be applied to the rotor shaft. Thus the mechanical power in equals the electrical power out (for an ideal generator).

I'm working on a really simple generator at the moment.
To answer your question in simple terms, the coils in the generator act like magnets of the opposite polarity to the actual magnets and they try to stay put holding back the input shaft, the more load the more hold back, you will allways put a little more energy into the generator as you take out.
Pretty much what Cruts just said.
Dont forget the power in the load has to come from whatever is turning the generator, it just converts rotating energy into electrical energy.

On a generator

Torque controls power (When the load increases, the prime mover has to work harder)

Excitation controls the power factor. By over or under exciting the field the power factor can be made leading or lagging.