DaveC wrote:
Looking to provide switching for 1-phase, 220 AC, 1/2 hp motor that
doesn't include use of a contactor. I appreciate the need for precise
current limit (LRA) that a branch breaker can't provide.

So, I choose to not have a contactor but instead, this, which
provides the power-fail protection:

http://www.amazon.com/Woodstock-D4160-110-Volt-Paddle-
Switch/dp/B005W17HYY/ref=pd_sim_hi_1/191-4569239-2528519

This has a relay (rated 1/2 hp) that drops out on power fail, and has
external connections for additional e-stop mushroom switch. But no
provision for motor protection.

Would 2 precisely-matched (ie, to the 1/4 amp), slow-blow HRC fuses be
sufficient to protect this motor?


Look at that switch again - it's a 110v switch, not a 220v switch. Hate to
see you order the wrong one. You could fuse the circuit behind the switch
but you'd have no way to ensure that both legs will drop out at the same
time the way that a breaker does. You would not want to find yourself in a
situation where one leg drops out but the other does not.

What is the application for this motor that requires so much more precision
than the circuit protection that a breaker would provide?

--

-Mike-