I have always used the 2N7000 for this.
Max,

 

So I suggest following the moderators admonitions and being more civil and not jumping down other people's throats.

So you really think answers like this are both safe and constructive?

The simplest soft-start solution is to use 200 feet of skinny extension cord.

 

Lets know the results.
Max.

Ok this has taken way longer than I expected but I'm declaring this a success. It's not perfect but it's pretty good. The updated schematic is below

• I've regulated the tablesaw to ~50% of the no load speed
• It has soft start and gets to the target speed in ~2secs, with a little overshoot.
• Under heavy load (cutting 40mm oak) it takes ~1sec to max out and engage the relay
• The TRIAC doesn't get hot enough to warrant a heatsink
• Speed is determined by measuring the current 500us before mains zero-cross
• I used a PD control algo

What would I do differently?

• Control the relay by sinking current from the PIC, since max Isink ~2* max Isource.
• Add a push button to aid debugging/tuning
• 
• 

 

It certainly looks like a good package, and from the description it appears to be meeting your needs, so that is great! Thanks for sharing the results! The long extension cord would have provided the soft start but it would also have had poor speed regulation. It is a cheap trick for some kinds of emergency situations, not at all efficient and far from optimum performance. But it did work once on a farm.
That is better than the table saw with a high powered induction motor, which has a large starting inrush and won't even run on a cheaper engine driven generator, although the numbers said it should.

 

You should give us the circuit and the specs of the motor.

 

You should give us the circuit and the specs of the motor.

 

You should give us the circuit and the specs of the motor.

The motor is a universal type, 1800W suited for 240VAC. I've already posted the full schematic.

 

I designed a similar system for soft starting power amps up to 2000watts.
It worked very well.
I just dropped mains through a resistor and diode into a capacitor then 5V1 zener for PIC power.
The opto isolator doesn't need much current.

 

I designed a similar system for soft starting power amps up to 2000watts.
It worked very well.
I just dropped mains through a resistor and diode into a capacitor then 5V1 zener for PIC power.
The opto isolator doesn't need much current.

I'm guessing you omitted the relay which requires ~30mA, or you used a ~10W resistor

 

The motor is a universal type, 1800W suited for 240VAC. I've already posted the full schematic.

Sorry about that I did not see it.