what does this part do?

[riverracer]

hi,
can anyone tell me what this box on top of the tm-2 cabinet does?
it looks like it has 2 kitchen stove heater elements in it.
just wondering, as machine works fine.

thanks

[Ken_Shea]

I've wondered that as well, going to take a guess that it functions as a over voltage take-up for the vector drive operation.

[juxtoposed]

Its a regen resistor. A motor becomes a generator when no voltage is put to it but it is still rotating, like on a decel or stop command. This resistor "uses" this voltage so it doesn't "spike" the system.

[gpcoe]

That should be the dynamic brake energy dump. As juxtoposed said, it's a resistive element and when the spindle stops, the output energy is dumped into that coil. Since the motor (essentially a generator at this point) has nothing driving it, the spindle quickly stops. If you've ever had a power outage while running you'll notice that it actually takes quite a while for the spindle to come to a stop. 5 minutes or so depending on the configuration.

One time, one of our VF-2 SS had the spindle drive fail and it applied the dynamic brake while still driving the spindle at 12k rpm. That sucker glowed bright red and caught the settled oil on the outside of that "hot" box on fire. Good times.

Greg

[Ydna]

We use it as a hotdog cooker...