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(07-27-2018, 10:01 AM)Huxleywood Wrote: The simplest method for adding an outboard stop switch to the VFD would be to use the micro-switch that should already be on the brake pedal. Press the brake pedal and it tells the drive to shut down. Obviously, you could add switches anywhere but the brake is already there and should be wired with a switch.
That may be the quickest that drive can brake the 514. Depending on the minimal ohmic value the drive can support and the particular dynamic braking resistor installed (if any) it just may not be able to stop it faster. Plus the old Delta 20" saws have pretty lightweight wheels, the 514 has more inertia to stop. In any event, the quickest was to stop this saw would be to use the largest braking resistor the drive can support and use the mechanical brake to trigger the stop/braking circuit on the drive as well as using the mechanical brake to help stop the saw. This should get the stopping time down significantly, even though Grizzly's foot brakes have never been the quickest on their own.
You and EvilTwin make good points. As you say, there is a micro switch attached to the foot brake which - when normally hooked up to 3-phase power, turns of the machine. When the original purchaser installed the VFD he said that he did not hook up that switch. There is probably a way to make the connection but I have no idea how. I've got the WEG manual but it is definitely written for someone who speaks electrical engineer talk - and that's not me! I've got a buddy who works as an industrial electrical engineer and will ask him to come take a look at the install. Having a functioning brake would be a nice-to-have. Thanks for your comments!
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(07-27-2018, 01:31 PM)dg152 Wrote: You and EvilTwin make good points. As you say, there is a micro switch attached to the foot brake which - when normally hooked up to 3-phase power, turns of the machine. When the original purchaser installed the VFD he said that he did not hook up that switch. There is probably a way to make the connection but I have no idea how. I've got the WEG manual but it is definitely written for someone who speaks electrical engineer talk - and that's not me! I've got a buddy who works as an industrial electrical engineer and will ask him to come take a look at the install. Having a functioning brake would be a nice-to-have. Thanks for your comments!
Almost all drives have low voltage multi-purpose circuits that will work to stop the motor. The micro-switch on the brake will be easy to use for that function, I have wired those numerous times. I am not familiar with that WEG but if you have the manual and your friend has any VFD experience at all there should be no problem wiring the brake up plus they could also adjust any parameters you like and show you how to do it. Motor drives like these aren't complicated at all, they just look like it when you have never seen/worked with one.
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You did very well IMO. The only thought I had is keep an eye on the temperature of the VFD if you run the saw for an extended period. I know virtually nothing about VFDs but thought they came with a fan for cooling. Make sure it doesn't get too warm.
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Kurt, you are correct. The VFD has an internal cooling fan much like, I imagine, a computer-type cooling fan. The original owner very cleverly used an ammo can to mount the VFD in. When in use the lid comes off for cooling. When unplugged the lid goes back on to help with dust control. I'll be watching it carefully to ensure that it doesn't get hot.
