On a small 2HP belt sander powered off of a VFD I wanted to put an across-the-line "E-stop" on the incoming 240Vac (1P) and was hoping to not have to add a control transformer and contactor; In other words just wire in a two pole switch.
I'm not seeing any contact blocks for 30mm switches rated for more than 6A. I was thinking more in the lines of 20A / 250 Vac
Am I dreaming?
What Stuart said. Wrong place. GOOD place for a "disconnect". I have both, right at the operator position.
Otherwise, you want the "brains" of a VFD (or DC Drive) to remain powered so they can do their programmed best at rapidly braking to a stop. Cannot do ANYTHING predictable if no power to their "smarts".
Belt sander of what size and configuration? Clothing could get caught? Probably not. So rapid braking maybe not a factor at all?
Now, think "lathe" instead of "belt sander" for a moment.
If/as/when/where you NEED that assured rapid stop, there should be a spring-actuated mechanical brake held-off by power. Most, not all, that would be at the motor.
THEN .. if the VFD (or DC drive) were to go nuts - say off a cut or broken control wire - and send RPM of a heavy or imbalanced workpiece in the direction of low-Earth orbit?
Slap THAT sort of E-stop, ALL power is cut, and the
brake saves the day.
That's where you came in this door. Cutting ALL power.
But should you also have a brake? Pass. I know nada about your situation.
Your shop. Your needs assessment. Your risk assessment. Your budget as well. Your plan to address them.
The technology is the easy part.