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Maynard A. Philbrook Jr.

In article ,
says...

A friend (in USA) with a 220v, 1-phase horizontal bandsaw in his home machine
shop wants to replace the 1/4 hp motor with 1/2 hp and rewire with an
auto-off switch (when the blade cuts through the metal).

I always default to using a 3-wire control with contactor, but he asks the
logical question: "Why?"

Other than the "If the power fails while cutting" answer (which he says seems
of limited additional value on a saw with auto-stop feature) I wasn't very
convincing.

What are the arguments for using a contactor as opposed to a simple on-off
switch of equivalent rating?

Thanks.

My cheap miller I use has a magnetic latch integrated into the
start/stop operator switch. it requires that you feed both the
L1 and L2 to it but only switches the L1 to the motor.

I've seen these also for three phase switching of motors so that
if you do lose power it will switch off the motor.

I guess it maybe a cost savings since it's much easier to put a
simple mechanical latch that is held with small solenoid than
putting in that extra crap.

Jamie